Thèses : « Asphalt cement »

1

Gouru, Harinath. « Laboratory evaluation of asphalt-portland cement concrete composite ». Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-12232009-020518/.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

2

Saboori, Arash. « Warm Mix Asphalt Processes Applicable to North Dakota ». Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26722.

Texte intégral

Résumé :

Warm mix asphalt (WMA) represents a group of technologies that allows production of asphalt mixtures at lower temperatures compared to traditional hot mix asphalt (HMA). This results in less fuel consumption and reduction in CO2 ?and fumes emission. This research was conducted in order to provide North Dakota department of transportation (NDDOT) with a thorough study on state of the practice of WMA in USA and compare WMA performance with HMA. Extensive literature study was conducted, collecting reports and field experiment data from DOTs of states with climate similar to ND. Viewpoints of experts in the field were collected and analyzed using a comprehensive survey. These were added to analysis of collected data on WMA performance. The research results suggest using foaming processes (Double Barrel Green in particular) and chemical additives (Evotherm in particular) at this early stage with guidelines for modifications in WMA specification and testing compared to HMA.
North Dakota Department of Transportation

Styles APA, Harvard, Vancouver, ISO, etc.

3

Hanson, Jon Russell. « Cracking and roughness of asphalt pavements constructed using cement-treated base materials / ». Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1233.pdf.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

4

Liu, Yongliang. « Static, dynamic mechanical and fatigue properties of cement-asphalt mortars ». Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10042034/.

Texte intégral

Résumé :

High-speed railway or rail (HSR) is a hot topic all over the contemporary world. And there is a growing tendency towards the application of nonballasted or slab tracks in HSR. Cement-asphalt mortar (CAM), a composite of Portland cement and asphalt emulsion, is widely used as a cushion layer in the two prevailing prefabricated concrete slab tracks of HSR in China, namely CRTS I and CRTS II. After a few years’ operation and service, however, premature cracking has been identified in the CAM layer along part of CRTS I and CRTS II. This is mainly caused by the fatigue of CAMs under repetitive traffic loading, that is, mechanical fatigue. In this research work, therefore, static, dynamic mechanical and most importantly, fatigue properties of the two typical CAMs, namely CAM-I and CAM-II, were investigated. Using a 4-point bending (4PB) test method, static or quasi-static mechanical properties of these two CAMs were studied. Results indicated that the 4PB test method was suitable for characterising their static bending properties in the laboratory, and more reliable results could be obtained, especially on modulus of elasticity, compared to the compression test method which was usually used for formulation design and quality evaluation. However, irrespective of the test methods used, CAM-I and CAM-II were found to be distinctively different in their static mechanical properties and behaviour at room temperature, due to the changes in the microstructures of their binding materials, cement-asphalt binder (CABs), used in CAMs at different A/Cs. The primary functions of CAMs as the cushion layer in CRTS I and II, especially damping, had been demonstrated to be in close relation to their viscoelasticity. Based on the DMA method, the temperature spectra of dynamical modulus and loss factors of CAMs or CABs were obtained to characterise their temperature susceptibility and viscoelasticity, respectively. On the temperature spectrum of CAM-I, the two characteristic temperatures of the asphalt binder, Tg implied to be around -20 °C and TR&B measured to be 48 °C, could be determined, andthese two not only defined the viscoelastic zone for CAM-I and the immediate temperature range for the fatigue tests of CAM-I, but also the two boundaries of service temperatures for CAM-I and CAM-II under traffic loads. The higher A/C caused a decrease in dynamic modulus of CAMs but an increase in their loss factors and temperature susceptibility, and a balance should be considered between them in the future design of new CAMs. For the first time, 4PB fatigue of CAM-I and CAM-II were investigated using two different fatigue test schemes, and the results indicated that, in terms of the fatigue behaviour, the CAM-I can be considered as a cement-modified asphalt mortar whilst CAM-II an asphalt-modified cement mortar. Therefore, it is preferable to use the asphalt mixture-based fatigue test configuration for CAM-I and this fatigue test scheme was an ideal one to be used. Additionally, it was found that low temperature was beneficial to the fatigue life of CAM-I whereas high temperature was detrimental to its fatigue life. On the other hand, the fatigue test configuration of cement-based materials including plain concretes is favourable to use for CAM-II but might not suitable for CAM-II, especially when the influence of the reversal stress, R, or the test temperature was separately considered. Different from plain concrete materials, the reversal stress or the test temperature had a significant impact on the fatigue life of CAM-II. Higher temperature would greatly reduce its fatigue life, and this temperature should not be higher than TR&B of the asphalt binder used. Much longer fatigue life of CAM-II was observed under low temperatures if the same stress, instead of normalised stress level, was applied, and CAM-II was more like plain concretes when temperature fell to around Tg of the asphalt binder.

Styles APA, Harvard, Vancouver, ISO, etc.

5

Brown, Ashley Vannoy. « Cement Stabilization of Aggregate Base Materials Blended with Reclaimed Asphalt Pavement ». Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1314.pdf.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

6

Lucena, Maria da ConceiÃÃo Cavalcante. « Chemical and rheological characterization of an asphalt cement(AC)modified polymers ». Universidade Federal do CearÃ, 2005. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1417.

Texte intégral

Résumé :

Neste trabalho foi realizado o estudo da caracterizaÃÃo quimica e reologica do cimento asfaltico produzido recentemente no pais, oriundo de petroleo do Campo Fazenda Alegre, no estado do Espirito Santo. Para efeito de comparaÃÃo, tambem foram estudados os asfaltos da refinaria Vale do Paraiba e os estrangeiros arabe e venezuelano. Os asfaltos foram modificados por incorporaÃÃo dos polimeros SBS e EVA, e os efeitos resultantes da modificaÃÃo foram avaliados. Os parÃmetros investigados visaram a avaliaÃÃo de problemas usuais como: deformaÃÃo permanente, trincas termicas e oxidaÃÃo. Os polimeros foram caracterizados atraves de termogravimetria e calorimetria exloratoria diferencial e por espectroscopia no infravermelho. Os asfaltos puros e modificados foram caracterizados por espectroscopia no infravermelho, ressonÃncia magnetica nuclear, calorimetria exploratoria diferencial, termogravimetria e cromatografia de permeaÃÃo em gel. A composiÃÃo quimica foi realizada atraves do fracionamento SARA e teor de enxofre. Ensaios empiricos como ponto d amolecimento, penetraÃÃo e retorno elastico tambem foram realizados. As propriedades reologicas foram avaliadas atravÃs da viscosidade absoluta e de ensaios dinÃmico-mecÃnicos. O envelhecimento oxidativo dos asfaltos foi avaliado a partir da analise dos espectros no infravermelho e de ressonÃncia magnÃtica nuclear, alem da variaÃÃo do modulo complexo de cisalhamento dinÃmico. Observou-se que os asfaltos brasileiros diferem em relaÃÃo aos teores de carbonos aromÃticos, quando comparados com o asfalto Ãrabe. Alem disso, apresentam comportamento diversos frente Ã presenÃa de oxigÃnio. Nos asfaltos modificados pos SBS, o ensaio de calorimetria exploratÃria diferencial mostrou uma diminuiÃÃo na transiÃÃo vÃtrea do material. A presenÃa do SBS aumentou a resistÃncia do asfalto ao processo oxidativo. A adiÃÃo do SBS e do EVA provocou um aumento da viscosidade do asfalto de forma nÃo linear indicando que os polÃmeros nÃo sÃo aditivos inertes. O comportamento Newtoniano nÃo foi verificado para os ligantes modificados. Ensaios dinÃmicos-mecÃnicos demonstraram que o SBS elevou o grau de desempenho dos ligantes. Os ensaios com as aparas da industria de calÃados (EVA), indicaram uma melhoria na elasticidade do ligante.
This work presents a study on chemical and rheological characterization of an asphalt cement (AC) recently produced in Brazil, originated of petroleum of the field of Fazenda Alegre at the state of EspÃrito Sa nto. A second Brazilian petroleum and also a foreign one were also studied, and their respective asphalts were compared to the Fazenda Alegre AC. The effect of polymers such as SBS and EVA on the chemical and rheological behavior of the investigated ACs was also object of the study. Typical pavement distresses were considered, such as permanent deformation, thermal cracking and oxidation. The polymers were examined using therm ogravimetry and differential scanning calorimetry and also infrared spectroscopy. Base and modi fied asphalt cements were characterized by infrared spectroscopy, nucl ear magnetic resonance, thermogravimetry, differential scanning calori metry and gel permeation chromatography. The chemical composition was found by the SARA method a nd the sulfur amount. Empirical tests such as softening point, penetration and elastic recovery were also performed. Rheological properties were determined by the absolute viscosity and dynamic mechanical analyses. The oxidative aging of asphalts was analyzed by the infrared and nuclear magnetic resonance as well by the variati on of complex shear modulus. The observed structural characteristics show ed that the Brazilian asphalt has a different structure when compared to foreign asphalts, evidenced by a different amount of aromatic carbon. In addition, the asphalts showed different beha vior when exposed to oxidative conditions. The differential scanning calorimetry results showed a decrease in glass transition temperatures in the polymer modi fied asphalts. The effect of SBS and EVA were also observed in the viscosity measurem ents. An increase in the absolute viscosity and a Non-Newtonian behavior was observe d. Therefore, polymers acted as non-inert additives. Dynamic mechanical analyses demonstrated that SBS increases the binder performance grade. The analyses performed in the asphalts modified by the residue of sandalâs industry showed an improvement in elasticity.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Ghavibazoo, Amir. « Characterization of Activities of Crumb Rubber in Interaction with Asphalt and its Effect on Final Properties ». Diss., North Dakota State University, 2014. http://hdl.handle.net/10365/24768.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

8

Ragab, Mohyeldin. « Enhancing the Performance of Crumb Rubber Modified Asphalt through Controlling the Internal Network Structure Developed ». Diss., North Dakota State University, 2016. http://hdl.handle.net/10365/25735.

Texte intégral

Résumé :

Sustainability presents a pathway for future generations to have a better life. Cradle to cradle methodology is the essence of sustainability. In cradle to cradle approach, we aim to reuti-lize a given waste instead of disposing or landfilling it. Each year, millions of waste tires are dis-posed of in landfills. This poses a major challenge environmentally and economically. Environ-mentally, those tires become prone to fire hazards as well as being a place for rodents and mos-quitos to reside at. Economically, on the other hand, each tire has an average of about 50% valu-able polymers as well as oily components. One of the methods to utilize the valuable raw materi-als in waste tires is to recycle it in the form of ground tire rubber also known as crumb rubber modifier (CRM). Although CRM has been widely used as an asphalt modifier, however, due to the complexity of asphalt as well as the waste nature of CRM, the full understanding of the CRM modification mechanism with asphalt has not been fully understood. Understanding of the modi-fication mechanisms involved in the CRM interaction with asphalt would enable us to produce a crumb rubber modified asphalt (CRMA) with enhanced properties. In the current research work, an attempt is made to better understand the mechanism of interaction between CRM and asphalt and the nature of components from asphalt and CRM that take part in the interaction between them. In addition, we investigate the effectiveness of CRM as a modifier for asphalt on the mac-ro and microscale aspects. Another part of the current research work deals with a second waste material; used motor oil. Used motor oil (UMO) presents yet another challenge to environment. With the ever increas-ing motor vehicles produced with advanced technologies and increased advanced motor oil de-mand. This presents a burden on the environment, with the continuous production of UMO. In the current research work, we investigated the feasibility of utilizing UMO as a modifier for asphalt and CRMA. We also investigated the effect of UMO on the micro and macroscale aspects of asphalt.

Styles APA, Harvard, Vancouver, ISO, etc.

9

Ghavibazoo, Amir. « Characterization of Activities of Crumb Rubber in Interaction with Asphalt and its Effect on Final Properties ». Diss., North Dakota State University, 2015. https://hdl.handle.net/10365/27474.

Texte intégral

Résumé :

Recycling of millions of scrap tires produced everyday is crucial challenge encountered by waste management systems. Recycling tire rubbers in form of ground tire rubber, known as crumb rubber modifier (CRM), in asphalt industry was introduced in early 1960's and is proved as an effective recycling method. Interaction between CRM and asphalt is physical in nature which happens mainly due to exchange of components between CRM and asphalt and enhances the time temperature dependant properties of asphalt. In this work, the interaction between CRM and asphalt was evaluated through monitoring the evolutions of CRM in asphalt in macro and micro-level. The mechanism and extent of CRM dissolution were monitored under several interaction conditions. The composition of materials released from CRM was investigated using thermo-gravimetric analysis (TGA). The molecular status of the released components were studied using gel permeation chromatography (GPC) analysis. The composition analysis indicated that the CRM start releasing its polymeric components into the asphalt matrix at dissolutions higher than 20%. The released polymeric component of CRM alters the microstructure of the asphalt and creates an internal network at certain interaction temperatures according to viscoelastic analysis. At these temperatures, the released polymeric components are at their highest molecular weight based on GPC results. The effect of released components of CRM on the time temperature dependent properties of asphalt and its glass transition kinetic was monitored using dynamic shear rheometer (DSR) and differential scanning calorimetry (DSC), respectively. The DSC results showed that the intensity of glass transition of the asphalt binder which is mainly defined by the aromatic components in asphalt reduced by absorption of these components by CRM. The evolution of CRM was investigated during short-term aging of the modified asphalt binder. In addition, the effect of presence of CRM and release of its component on oxidization of asphalt binder was evaluated using Fourier transform infrared spectroscopy (FTIR). The results revealed that CRM continue absorbing the aromatic components of asphalt during aging which stiffen the asphalt binder. Also, it was observed that release of oily components of the CRM, which contain antioxidant, reduces oxidization rate of asphalt significantly.
National Science Foundatio (Grant No. 0846861)

Styles APA, Harvard, Vancouver, ISO, etc.

10

Bermel, Bethany Noel. « Feasibility of reclaimed asphalt pavement as aggregate in Portland cement concrete pavement ». Thesis, Montana State University, 2011. http://etd.lib.montana.edu/etd/2011/bermel/BermelB0811.pdf.

Texte intégral

Résumé :

Each year, the US highway industry produces over 100 million tons of reclaimed asphalt pavement (RAP) through the rehabilitation and construction of the nation's roads. Using RAP as aggregate in Portland cement concrete pavement (PCCP) is one attractive application for a further use of this recyclable material. Earlier research has demonstrated the feasibility of creating concrete with RAP aggregate; however, prior studies focus on mechanical properties of the material. This research project will further distinguish the properties of this material and draw conclusions on the concrete's aptness for use as a pavement in Montana. This thesis encompasses the development of candidate RAP in PCCP mixtures that will subsequently move forward for a more thorough evaluation of their material properties. The mixing experiment and preliminary testing phases of this project provided information to draw a number of conclusions about the appropriateness of RAP aggregate in PCCP, including: (1) using conventional practices, PCCP containing RAP aggregate (20 percent fine and 45 percent coarse) can achieve compressive strengths in excess of 3,000-psi; (2) as the RAP replacement rate is increased, the compressive strength of the concrete decreases; (3) fine RAP aggregate appears to have a more detrimental effect on the concrete than coarse aggregate; (4) concretes with a relatively high RAP replacement rate (50 percent fine and 100 percent coarse) may be suitable for transportation applications; (5) at high RAP replacement rates, there appears to be a benefit (relative to concrete strength) in using increased replacements of both fine and coarse RAP, rather than singly replacing just one aggregate gradation; and (6) concrete containing RAP displays increased flexural strengths as compared to traditional PCCP. This material research was performed using a Design of Experiments (DOE) method. The suitability of this statistical method as a mix design development tool was characterized through several important findings, which include: (1) the DOE method was effective in distinguishing mixture behaviors; (2) mix design optimization is readily accomplished using the statistical model generated from the DOE data; and (3) variability in the concrete mixing and testing processes has a significant effect on the capabilities of the statistical model.

Styles APA, Harvard, Vancouver, ISO, etc.

11

Gul, Waqar Ahmed Waqar. « Effect Of Recycled Cement Concrete Content On Rutting Behavior Of Asphalt Concrete ». Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609765/index.pdf.

Texte intégral

Résumé :

Disposed waste materials remained from demolished buildings have been an environmental problem especially for developing countries. Recycled Cement Concrete (RCC) is one of the abundant components of waste materials that include quality aggregates. Use of RCC in asphalt concrete pavements is economically a feasible option as it not only helps in recycling waste materials but also preserves natural resources by fulfilling the demand for quality aggregate in pavement constructions. However, due to variability in RCC characteristics, a detailed evaluation of its effect on asphalt concrete performance is required. In this study, effect of RCC content on rutting potential of asphalt concrete is investigated using laboratory prepared specimens. Rutting susceptibility of the specimens is determined using repeated creep tests performed in the uniaxial stress mode. Because of the aspect ratio requirements for the repeated creep test, the standard Marshall mix design procedures were modified based on the energy concept by changing the compactor device and the applied design number of blows. The modified specimens were tested to determine a number of parameters that can describe the rutting behavior of the tested mixes. The findings indicate that slope constant and flow number give relatively stronger relationships with rutting behavior as compared to the other rutting parameters. While increasing the RCC content yields improved rutting performance for coarse graded specimens, it dramatically reduces the performance for fine graded specimens.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Hanson, Jonathan Russell. « Cracking and Roughness of Asphalt Pavements Constructed Using Cement-Treated Base Materials ». BYU ScholarsArchive, 2006. https://scholarsarchive.byu.edu/etd/396.

Texte intégral

Résumé :

While cement treatment is a proven method for improving the strength and durability of soils and aggregates, cement hydration causes shrinkage strains in the cement-treated base (CTB) that can lead to reflection cracking in asphalt surfaces. Cracking may then cause increased pavement roughness and lead to poor ride quality. The overall purpose of this research was to utilize data collected through the Long-Term Pavement Performance (LTPP) program to investigate the use and classification of CTB layers and evaluate the relative impact of cement content on the development of roughness and cracking in asphalt concrete (AC) pavements constructed using CTB layers. The data included 52 LTPP test sites, which represented 13 different states and one Canadian province, with cement contents ranging from 3.0 to 9.5 percent by weight of dry aggregate. Statistical procedures were utilized to identify the factors that were most correlated to the observed pavement performance and to develop prediction equations that transportation agencies can use to estimate the amount of roughness for a given pavement at a given age and the amount of distress associated with a particular crack severity level for a given pavement. The data collected for this study suggest that wide ranges of cement contents are used to stabilize soils within individual American Association of State Highway and Transportation Officials soil classifications. The data also suggest that CTBs comprising flexible pavement structures are constructed mainly on rural facilities. A backward-selection model development technique was used to develop sets of prediction equations for roughness and cracking. Age, AC thickness, CTB thickness, and cement content were determined to be significant predictors of International Roughness Index, while age, air freezing index, AC thickness, CTB thickness, cement content, and traffic loads in thousands of equivalent single-axle loads were determined to be significant predictors of low-severity, medium-severity, and high-severity block, fatigue, longitudinal (wheel-path and non-wheel-path), and transverse cracking in AC pavements constructed using CTB layers. Investigation of the relationships between CTB modulus and the development of roughness and cracking is recommended for further study.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Moss, Steven Phillip. « Experimental study for asphalt emulsion treated base ». To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

14

In, Chi-Won. « Defect characterization in heterogeneous civil materials using ultrasound ». Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47545.

Texte intégral

Résumé :

Asphalt and Portland cement concrete constitutes a significant portion of the total infrastructure all over the world. It has been reported that much of this concrete infrastructure is now approaching or has already passed its original design life. Thus it is critical to be able to quantitatively assess the condition of these concrete components. In order to rehabilitate or repair the civil infrastructure, nondestructive evaluation (NDE) techniques have been of great interest for infrastructure management agencies. However concrete components present several specific NDE challenges that must be addressed. . Concrete naturally exhibits large scale heterogeneous microstructure with a great deal of local material property variability, For this reasons, many conventional NDE techniques that work well for steel and other homogeneous materials cannot be applied to concrete; concrete is unable to transmit high frequencies, as the heterogeneity of the concrete causes signals of smaller wavelengths or wavelengths equal to the nominal aggregate size to be scattered and severely attenuated. Nevertheless, progress has been made towards accurate and reliable in-place NDE of concrete structures and materials, for example impact echo, ultrasonic pulse velocity method, and the ultrasonic wave transmission method. However, the detection of smaller sized defects or remote defects that are located away from the testing location still pose problems. In addition, the large size and potential limited access conditions of civil structures raise additional challenges. To overcome the limitations of current NDE techniques for concrete, this research considers two different types of ultrasonic waves (coherent and incoherent wave) to quantitatively characterize and monitor defects in heterogeneous concrete materials. The global objective of this research is to determine the feasibility and applicability of using these ultrasonic waves as a global, rapid, reliable, and non-biased technique for the routine screening of defects or monitoring of concrete structures and materials. Three different problems are considered: 1) characterization of segregation in asphaltic concrete, 2) crack depth determination in pier cap of concrete bridge structure, and 3) monitoring of self-healing process in cement-based concrete.

Styles APA, Harvard, Vancouver, ISO, etc.

15

Alattar, Iyad Ahmed. « Evaluation of Troxler 3241-C nuclear asphalt content gauge used for Marshall specimens ». Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-12042009-020138/.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

16

Tabbert, Toni Raenette. « Verification of the whitetopping thickness design procedure for asphalt concrete overlaid Portland cement concrete pavements ». [Ames, Iowa : Iowa State University], 2006.

Trouver le texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

17

Abbas, Abbas Musa. « Stiffness and deformation properties of asphalt open graded friction course containing cement coated natural aggregates ». Thesis, Liverpool John Moores University, 2010. http://researchonline.ljmu.ac.uk/5982/.

Texte intégral

Résumé :

The primary objective of this research study was to observe the changes in the physical properties of cement coated secondary aggregates, namely surface roughness and angle of internal friction and how these properties are related to the performance of Open Graded Friction Course asphalt mixtures, OGFC made from these materials under laboratory Uniaxial, deformation and rutting testing simulating the traffic loading and temperature of the materials in service. The secondary aggregates, namely Croxden natural gravel aggregates, which is rejected by road engineers for use in road surfacing was upgraded with a specifically designed cement coating. Asphalt mixtures mechanical properties in terms of stiffness modulus, deformations and rutting were determined and analyzed using state-of-the-art laboratory test equipment and supported by technical literature from different information and resources. Three aggregate types were considered in this study; Arcow rock crushed aggregates( as a control aggregate), Croxden aggregate (as a secondary or low quality aggregates) and cement coated Croxden aggregate (as an upgraded material). One aggregate gradation was designed for all mixture types and the adopted aggregate gradation had a nominal maximum aggregate size (NMAS) of 14mm. Two binder types were selected, 100/150 pen binder and 40/60 pen binder to represent the soft and hard binders respectively that are commonly used by road engineers. This research also documents a survey of literature review that led to the design of a novel machine that is eagerly needed by the pavement industry to boost the knowledge and understanding of real tyre-road interaction. Computer software, SOLIDWORKS, was used to create a 3-dimentional model of the machine that was jointly named by the Highway Agency and Tarmac ltd., as Low Cost Asphalt Tasting Equipment (LoCATE). The machine was designed for use and for the first time to investigate the performance of the said mixtures under real traffic loading and environmental conditions and to correlate its results with those obtained using Repeated Load Indirect Tensile Test (RLIT) and Repeated Load Axial Test (RLAT), which were carried out at 10°C, 20°C, 30°C and 45°C. At an advanced stage of this research work and when the cost of fabricating LoCATE was found impossible to be met by LJMU, wheel tracking tests were done on the materials studied as a replacement of LoCATE and this part of the research program was achieved at Wolverhampton's bituminous testing laboratories in collaboration with Tarmac Ltd. In general, the results of this research investigation indicate that the introduction of cement coated aggregates to OGFC led to an outstanding improvement in the chemical properties of the coated natural aggregates and the stiffness and deformation properties/resistance of the road mixtures containing them. This was in comparison with that made from the uncoated aggregates in all the tests that have been carried out within this research study. Also, the effects of elevated temperature were investigated and it was found to have significant influence on the engineering properties, Indirect Tensile Stiffness Moduli (ITSM) and permanent deformation/rutting characteristic of the mixtures were also investigated. Outstanding new results were achieved, using LJMU cement coating paste for coating the waste natural aggregate and as thus this will hopefully eliminate the restriction imposed by road engineers on the use of natural gravel aggregates in road pavement surfacing layers. This is an outstanding knowledge extension in this field and marks a starting point for more research in this ever growing industry i. e. the use of waste and recycled aggregates in construction industry.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Dixon, Paul A. « Factors Affecting the Strength of Road Base Stabilized with Cement Slurry or Dry Cement in Conjunction with Full-Depth Reclamation ». BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2629.

Texte intégral

Résumé :

Full-depth reclamation (FDR) in conjunction with cement stabilization is an established practice for rehabilitating deteriorating asphalt roads. Conventionally, FDR uses dry cement powder applied with a pneumatic spreader, creating undesirable fugitive cement dust. The cement dust poses a nuisance and, when inhaled, a health threat. Consequently, FDR in conjunction with conventional cement stabilization cannot generally be used in urban areas. To solve the problem of fugitive cement dust, the use of cement slurry, prepared by combining cement powder and water, has been proposed to allow cement stabilization to be utilized in urban areas. However, using cement slurry introduces several factors not associated with using dry cement that may affect road base strength, dry density (DD), and moisture content (MC). The objectives of this research were to 1) identify construction-related factors that influence the strength of road base treated with cement slurry in conjunction with FDR and quantify the effects of these factors and 2) compare the strength of road base treated with cement slurry with that of road base treated with dry cement. To achieve the research objectives, road base taken from an FDR project was subjected to extensive full-factorial laboratory testing. The 7-day unconfined compressive strength (UCS), DD, and MC were measured as dependent variables, while independent variables included cement content; slurry water batching temperature; cement slurry aging temperature; cement slurry aging time; presence of a set-retarding, water-reducing admixture; and aggregate-slurry mixing time. This research suggests that, when road base is stabilized with cement slurry in conjunction with FDR, the slurry water batching temperature; haul time; environmental temperature; and presence of a set-retarding, water-reducing admixture will not significantly affect the strength of CTB, provided that those factors fall within the limits explored in this research and are applied to a road base with similar properties. Cement content and cement-aggregate mixing time are positively correlated with the strength of CTB regardless of cement form. Additionally, using cement slurry will result in slightly lower strength values than using dry cement.

Styles APA, Harvard, Vancouver, ISO, etc.

19

Boyes, Anthony John. « Reducing Moisture Damage in Asphalt Mixes Using Recycled Waste Additives ». DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/654.

Texte intégral

Résumé :

This thesis has determined that using fly ash as a mineral filler in asphalt pavements can help strengthen and reduce asphalt moisture damage. Also, dynamic shear rheometer tests show that these additives have a stiffening effect on asphalt binder. Moisture related damage is considered one of the main causes of asphalt pavement failure. As water infiltrates a layer of asphalt, it slowly strips away asphalt binder, weakening the aggregate/binder bond. This process, combined with the cyclic loading of traffic, can lead to several different types of asphalt failure including rutting, raveling, bleeding, and cracking. For several decades, research has been conducted to find a solution to this problem. Currently in practice, hydrated lime and a variety of amine-based chemicals are being used as anti-stripping agents. However, as an emphasis towards sustainability has increased, waste products are now being investigated for this purpose. This thesis investigated the anti-stripping effectiveness of two waste products: fly ash and cement kiln dust (CKD), and compared them with hydrated lime and an amine-based chemical additive. The results indicate that class C fly ash can be used as an asphalt anti-stripping additive; however it is more costly than lime or amine chemicals.

Styles APA, Harvard, Vancouver, ISO, etc.

20

Tighe, Susan Louise. « An integrated model to assess asphalt cement quality on low-temperature performance and life cycle cost ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0026/NQ51232.pdf.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

21

Tolbert, Jacob Clark. « Effect of High Percentages of Reclaimed Asphalt Pavement on Mechanical Properties of Cement-Treated Base Material ». BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4217.

Texte intégral

Résumé :

Full-depth reclamation (FDR) is an increasingly common technique that is used to rehabilitate flexible pavements. Implementation of FDR on rehabilitation projects produces several desirable benefits. However, these benefits are not fully realized due to the fact that state department of transportation specifications typically limit the reclaimed asphalt pavement (RAP) content of pavement base material to 50 percent. The objective of this research was to evaluate the effects of RAP content, cement content, temperature, curing time, curing condition, and moisture state on the strength, stiffness, and deformation characteristics of cement-treated base (CTB) mixtures containing high percentages of RAP.For this research, one aggregate base material and one RAP material were used for all samples. RAP content ranged from 0 to 100 percent in increments of 25 percent, and low, medium, and high cement levels corresponding to 7-day unconfined compressive strength (UCS) values of 200, 400, and 600 psi, respectively, were selected for testing. Moisture-density, UCS, resilient modulus, and permanent deformation tests were performed for various combinations of factors, and several statistical analyses were utilized to evaluate the results of the UCS, resilient modulus, and permanent deformation testing.The results of this work show that CTB containing RAP can be made to achieve 7-day UCS values approaching 600 psi regardless of RAP content. With regards to stiffness, the data collected in this study indicate that the resilient modulus of CTB containing RAP is affected by temperature in the range from 72 to 140Â°F for the low cement level. Permanent deformation of CTB containing RAP is significantly affected by RAP content and cement level at the test temperature of 140Â°F. At the low cement level, temperature is also a significant variable. As the 7-day UCS reaches approximately 400 psi, permanent deformation is reduced to negligible quantities. The results of this research indicate that the inverse relationship observed between permanent deformation and 7-day UCS is statistically significant.Given that the principle conclusion from this work is that CTB with high RAP contents can perform satisfactorily as a base material when a sufficient amount of cement is applied, agencies currently specifying limits on the percentage of RAP that can be used as a part of reclaimed base material in the FDR process should reevaluate their policies and specifications with the goal of allowing the use of high RAP contents where appropriate.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Andrade, Lucas Rodrigues de. « Comparação do comportamento de pavimentos asfálticos com camadas de base granular, tratada com cimento e com estabilizantes asfálticos para tráfego muito pesado ». Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3138/tde-13032017-095746/.

Texte intégral

Résumé :

A engenharia rodoviária emprega pistas-teste para avaliação de materiais, do dimensionamento estrutural e de métodos executivos de pavimentos, de modo a submeter a estrutura de pavimentos a condições reais de clima e de tráfego. Há no mundo numerosos programas de monitoramento de pistas-teste que vêm contribuindo significativamente para o avanço da tecnologia dos pavimentos. Neste contexto, o presente trabalho se propõe a avaliar o desempenho de quatro segmentos asfálticos sequenciais de um trecho experimental executado na Rodovia Fernão Dias (BR-381), que liga as cidades de São Paulo a Belo Horizonte, sob concessão pela empresa ARTERIS, sujeita a tráfego muito pesado. As estruturas de pavimentos construídas para este estudo são: pavimento flexível executado com base de Brita Graduada Simples (BGS), pavimento semirrígido executado com base de Brita Graduada Tratada com Cimento (BGTC), pavimento com base asfáltica constituída de material fresado (RAP) estabilizado com emulsão asfáltica e pavimento com base asfáltica constituída de material fresado (RAP) estabilizado com espuma de asfalto. A avaliação do desempenho foi realizada a partir de análises dos resultados de monitoramentos funcionais e estruturais realizados em campo periodicamente até a idade de 15 meses. Em laboratório, realizou-se a caracterização dos materiais empregados na construção utilizando o módulo de resiliência como parâmetro para avaliar a rigidez dos mesmos. A partir de análises funcionais, procedeu-se à avaliação da progressão de defeitos, dentre eles a irregularidade longitudinal, afundamentos em trilha de roda e características de superfície. Como foco principal, foram analisados o comportamento mecânico de cada segmento. As bacias de deslocamentos foram avaliadas por meio de indicadores estruturais e utilizadas para realização de retroanálises com o objetivo de estudar a variação destes indicadores e dos módulos das camadas, a depender do volume de tráfego acumulado e condições climáticas. Estes dados foram também empregados para relacionar as estruturas com os defeitos de superfície, além de alimentar um modelo computacional em elementos finitos que descreve o comportamento mecânico dessas estruturas. Os resultados obtidos nos monitoramentos periódicos e nas análises realizadas mostraram que o pavimento flexível não é adequado ao tráfego muito pesado e a partir dos 12 meses não atendia os limites da ANTT para rodovias sob concessão federal, enquanto o pavimento semirrígido mostrou-se adequado e estável ao longo do período estudado e os pavimentos reciclados apresentaram um ganho nos parâmetros estudados, devido ao processo de cura dos materiais utilizados, além de comportamento adequado ao tráfego submetido.
The highway engineering adopts road tests to evaluate pavement materials, structural design methods and pavement construction characteristics, with the goal of subjecting the pavement structure to real climate and traffic conditions. There are several road test monitoring programs worldwide, which significantly contribute to pavement technology development. The present study evaluates the performance of four pavement sections within a road test located in Rodovia Fernão Dias (BR-381), that connects São Paulo and Belo Horizonte cities under concession of Arteris, and is subjected to heavy traffic. The pavement structures built can be described as follows: flexible pavement with crushed stone base layer, semirigid pavement with cement-treated crushed stone base layer, pavement with base layer of RAP stabilized with emulsion asphalt and pavement with base layer of RAP stabilized with foamed asphalt. The pavement performance was evaluated by means of a functional and structural periodic field monitoring during 15 months. In laboratory, the materials stiffness was characterized from resilient modulus tests. The functional analysis was conducted to study the progression of pavement distresses, such as roughness, rutting and surface characteristics. Furthermore, as the main focus structural aspects were analyzed. Deflection basins were evaluated from its parameters and used for backcalculated moduli analysis, with the objective of comprehend the susceptibility of these parameters and layers moduli to climate and traffic conditions. These results were used to compare the structures with surface distresses, and were also used as input of a computational finite element model to describe the mechanical behavior of these structures. The results obtained from the periodic monitoring and analysis showed that the flexible pavement is not suitable for very heavy traffic and from the 12 months it did not meet the ANTT limits required for highways under federal concession, while the semi-rigid pavement proved to be adequate and stable during the studied period and the recycled pavements with presented an improvement in the studied parameters, due to the curing process of the materials used, and also presented adequate behavior to the submitted traffic.

Styles APA, Harvard, Vancouver, ISO, etc.

23

Garibay, Jose Luis. « Guideline for pulverization of stabilized bases ». To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

24

Dye, Jeremy Brooks. « Comparison of Winter Temperature Profiles in Asphalt and Concrete Pavements ». BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2240.

Texte intégral

Résumé :

Because winter maintenance is so costly, Utah Department of Transportation (UDOT) personnel asked researchers at Brigham Young University to determine whether asphalt or concrete pavements require more winter maintenance. Differing thermal properties suggest that, for the same environmental conditions, asphalt and concrete pavements will have different temperature profiles. Climatological data from 22 environmental sensor stations (ESSs) near asphalt roads and nine ESSs near concrete roads were used to 1) determine which pavement type has higher surface temperatures in winter and 2) compare the subsurface temperatures under asphalt and concrete pavements to determine the pavement type below which more freeze-thaw cycles of the underlying soil occur. Twelve continuous months of climatological data, primarily from the 2009 calendar year, were acquired from the road weather information system operated by UDOT, and erroneous data were removed from the data set. To predict pavement surface temperature, a multiple linear regression was performed with input parameters of pavement type, time period, and air temperature. Similarly, a multiple linear regression was performed to predict the number of subsurface freeze-thaw cycles, based on month, latitude, elevation, and pavement type. A finite-difference model was created to model surface temperatures of asphalt and concrete pavements based on air temperature and incoming radiation. The statistical analysis predicting pavement surface temperatures showed that, for near-freezing conditions, asphalt is better in the afternoon, and concrete is better for other times of the day, but that neither pavement type is better, on average. Asphalt and concrete are equally likely to collect snow or ice on their surfaces, and both pavements are expected to require equal amounts of winter maintenance, on average. Finite-difference analysis results confirmed that, for times of low incident radiation (night), concrete reaches higher temperatures than asphalt, and for times of high incident radiation (day), asphalt reaches higher temperatures than concrete. The regression equation predicting the number of subsurface freeze-thaw cycles provided estimates that did not correlate well with measured values. Consequently, an entirely different analysis must be conducted with different input variables. Data that were not available for this research but are likely necessary in estimating the number of freeze-thaw cycles under the pavement include pavement layer thicknesses, layer types, and layer moisture contents.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Andrade, JosÃ Roberto Moreira de. « The effect of modification asphalt binder with a phenolic rein : cardanol-formaldehyde ». Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16820.

Texte intégral

Résumé :

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
The asphalt from petroleum refineries, when presents proper consistency to pavement, is denominated asphaltic binder or petroleum asphaltic cement (PAC). The petroleum asphaltic binders are materials constituted by complex mixtures of high-molecular-weight hydrocarbons. Their main components are carbon, hydrogen, but also contain other elements like oxygen, sulphur and some metals. They are obtained from the natural evaporation of deposits located on the earth surface (natural asphalt), or by distillation in industrial units specially designed for this. The asphaltic binders produced by petroleum refining resist satisfactorily in most situations to which pavements are submitted. Nevertheless, over the past years, the highways with a high volume of traffic have had to support an increasing daily average of vehicles, heavier trucks, and also increases in axle weight and in tire pressure. These roads require, thus, asphaltic coatings with better performance and more modern constructive techniques. In view of this, this research has as its goal to study the effects resulting from the modification of the petroleum asphaltic cement (PAC) by the addiction of a resin of the type phenol-formaldehyde â obtained from cardanol â to analysis of the feasibility of this additive in asphalts. Through this study, it was found that the additive enabled an increase in the module (G*) and a lowering of the phase angle (δ) that resulted in a better performance of the asphaltic binder in terms of permanent deformation if compared to the pure PAC. It was also observed a reduction of approximately 12ÂC in the temperature of compaction and machining of the mixture in relation to the pure binder, what makes possible the use of the resin as additive in asphaltic binders.
O asfalto obtido das refinarias de petrÃleo, quando apresenta consistÃncia adequada Ã pavimentaÃÃo, Ã denominado de ligante asfÃltico ou cimento asfÃltico de petrÃleo (CAP). Os ligantes asfÃlticos de petrÃleo sÃo materiais constituÃdos por misturas complexas de hidrocarbonetos de elevada massa molar, cujos componentes principais sÃo o carbono e o hidrogÃnio, contendo tambÃm outros elementos como o oxigÃnio, enxofre e alguns metais. SÃo obtidos por evaporaÃÃo natural de depÃsitos localizados na superfÃcie da terra (asfaltos naturais), ou por destilaÃÃo em unidades industriais especialmente projetadas. Os ligantes asfÃlticos produzidos pelo refino do petrÃleo atendem satisfatoriamente Ã maioria das situaÃÃes Ãs quais os pavimentos sÃo submetidos. Contudo, nos Ãltimos anos, as rodovias de alto volume de trÃfego apresentam aumento no VMD (nÃmero de veÃculos mÃdio diÃrio), maior peso nos caminhÃes, aumento da carga por eixo e aumento da pressÃo dos pneus, requerendo revestimentos asfÃlticos que apresentem melhor desempenho e tÃcnicas construtivas mais modernas. Em vista disso, este trabalho tem como objetivo estudar os efeitos resultantes da modificaÃÃo do cimento asfÃltico de petrÃleo (CAP) por adiÃÃo de uma resina do tipo fenol-formaldeÃdo â obtida a partir do cardanol â para anÃlise da viabilidade do uso deste aditivo em asfaltos. Por meio deste estudo verificou-se que o aditivo possibilitou um aumento no mÃdulo complexo (G*) e um abaixamento do Ãngulo de fase (δ) o que fez com que o ligante asfÃtico obtivesse um melhor desempenho em relaÃÃo a deformaÃÃo permanente comparado ao CAP puro. Verificou-se, tambÃm, uma reduÃÃo de aproximadamente 12 ÂC na temperatura de compactaÃÃo e usinagem da mistura em relaÃÃo ao ligante puro, o que torna viÃvel a utilizaÃÃo da resina como aditivo em ligantes asfÃlticos.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Hope, Charles A. « Evaluation of Portable Devices for Monitoring Microcracking of Cement-Treated Base Layers ». BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2965.

Texte intégral

Résumé :

A relatively new method used to reduce the amount of cement-treated base (CTB) shrinkage cracking is microcracking of the CTB shortly after construction. Three portable instruments used in this study for monitoring the microcracking process include the heavy Clegg impact soil tester (CIST), portable falling-weight deflectometer (PFWD), and soil stiffness gauge (SSG). The specific objectives of this research were 1) to evaluate the sensitivity of each of the three portable instruments to microcracking, and 2) to compare measurements of CTB stiffness reduction obtained using the three devices. The test locations included in this study were Redwood Drive and Dale Avenue in Salt Lake City, Utah; 300 South in Spanish Fork, Utah; and a private access road in Wyoming. Experimental testing in the field consisted of randomized stationing at each site; sampling the CTB immediately after the cement was mixed into the reclaimed base material; compacting specimens for laboratory testing; and testing the CTB immediately after construction, immediately before microcracking, immediately after each pass of the vibratory roller during the microcracking process, and, in some instances, three days after microcracking. Several linear regression analyses were performed after data were collected using the CIST, PFWD, and SSG during the microcracking process to meet the objectives of this research. Results from the statistical analyses designed to evaluate the sensitivity of each of the three portable instruments to microcracking indicate that the PFWD and SSG are sensitive to microcracking, while the CIST is insensitive to microcracking. Results from the statistical analyses designed to compare measurements of CTB stiffness reduction demonstrate that neither of the instrument correlations involving the CIST are statistically significant. Only the correlation between the PFWD and SSG was shown to be statistically significant. Given the results of this research, engineers and contractors should utilize the PFWD or SSG for monitoring microcracking of CTB layers. The heavy CIST is unsuitable for monitoring microcracking and should not be used. For deriving target CTB stiffness reductions measured using either the PFWD or SSG from specified targets measured using the other, engineers and contractors should utilize the correlation chart developed in this research.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Rodrigues, Andréa Ribeiro da Silva. « Caracterização química e reológica do cimento asfáltico de petróleo utilizado na cidade de Manaus modificado por borracha moída de pneus inservíveis e polímeros ». Universidade Federal do Amazonas, 2006. http://tede.ufam.edu.br/handle/tede/2523.

Texte intégral

Résumé :

Made available in DSpace on 2015-04-11T13:53:53Z (GMT). No. of bitstreams: 1 andrea.pdf: 2836298 bytes, checksum: df566d388fe30cef77051925ae2848ba (MD5) Previous issue date: 2006-06-15
In this research was made the study of the rheological and chemical properties of the conventional asphalt cements usually used in the city of Manaus and the same modified by addition with scrap tire rubber and polymers, as form to improve the characteristics and performance of local asphalt coverings. The scrap tire rubber has shown a valuable environmental and socially alternative adjusted being able to present great reductions of volume of this residue in the environment, added to the reduction maintenance costs of the pavements. Also they had been studied modified asphalts for copolymers SBS, SBR and EVA. The adopted methodology was directed, mainly, for the characterization of these asphalts in situations that are submitted in the process of mixes and life of service, have given emphasis the usually found problems in the pavement, such as permanent deformation, fatigue cracking and aging process. The adopted methodology was based on empirical tests and the Superpave specifications. The effect of the oxidation was verified by equipment that simulates the oxidative aging suffered for the asphalt during the mixes and its life of service, considering in the maximum ten years of use as floor. The results, evidenced that the use of modified asphalt by polymers and tire rubber presents improvements in the rheological and chemical properties of the asphalt contributing for the increase of the resistance of the bituminous covering.
Neste trabalho foi realizado o estudo das propriedades reológicas e químicas do ligante asfáltico, usualmente utilizado na cidade de Manaus, e o mesmo ligante modificado pela adição de borracha moída de pneus inservíveis e polímeros, como forma de melhorar as características e desempenho dos revestimentos asfálticos locais, além de proporcionar a redução de custos de manutenção dos pavimentos. A utilização de borracha moída de pneus inservíveis tem se mostrado uma alternativa valiosa, ambientalmente e socialmente adequada podendo apresentar redução desse resíduo no meio ambiente, onde se encontram propícios ao acúmulo de água ocasionando a proliferação de vetores de doenças. Também foram estudados ligantes modificados por copolímeros SBS, SBR e EVA. A metodologia adotada foi dirigida, principalmente, para a caracterização destes ligantes em situações a que são submetidos no processo de usinagem e vida de serviço, dando ênfase a problemas usualmente encontrados na pavimentação, tais como deformação permanente, trincas por fadiga e envelhecimento oxidativo. Os ensaios experimentais foram baseados em ensaios empíricos e nas especificações Superpave. O efeito da oxidação foi verificado por equipamentos que simulam o envelhecimento sofrido pelo ligante durante a usinagem e durante sua vida de serviço, considerando no máximo dez anos de uso como pavimento. Com base nos resultados dos ensaios, constatou-se que a utilização de ligantes asfálticos modificados por polímeros e borracha moída de pneus apresenta melhoras nas propriedades reológicas e químicas dos ligantes asfálticos contribuindo para o aumento da resistência do revestimento betuminoso.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Rogers, Tyler J. « Variability in Construction of Cement-Treated Base Layers : Probabilistic Analysis of Pavement Life Using Mechanistic-Empirical Approach ». Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd3273.pdf.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

29

SILVA, José de Arimatéia Almeida e. « Utilização do politereftalato de etileno (PET) em misturas asfálticas ». Universidade Federal de Campina Grande, 2015. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/878.

Texte intégral

Résumé :

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-05T00:24:48Z No. of bitstreams: 1 JOSÉ DE ARIMATÉIA ALMEIDA E SILVA – TESE (PPGEP) 2015.pdf: 6946608 bytes, checksum: 04efbba58513fb4cbcc2225d2ade0888 (MD5)
Made available in DSpace on 2018-06-05T00:24:48Z (GMT). No. of bitstreams: 1 JOSÉ DE ARIMATÉIA ALMEIDA E SILVA – TESE (PPGEP) 2015.pdf: 6946608 bytes, checksum: 04efbba58513fb4cbcc2225d2ade0888 (MD5) Previous issue date: 2015-06-26
Capes
A adição do resíduo de Politereftalato de Etileno (PET) em Cimentos Asfálticos de Petróleo (CAP), triturados em partículas cujo diâmetro está entre 0,6 e 0,074 mm, pode ser uma alternativa técnica viável para melhorar as propriedades mecânicas e reológicas das misturas asfálticas. Esta adição tem como finalidade proporcionar uma menor susceptibilidade das misturas asfálticas a fadiga e, conseqüentemente aumentar a vida útil de revestimentos asfálticos em regiões com clima tropical e a temperaturas elevadas. Este trabalho tem como objetivo principal a incorporação de um aditivo no Cimento Asfáltico de Petróleo. A adição de PET foi realizada em proporções de 4%, 5% e 6% relativas ao peso do teor de CAP ótimo e mensuradas as propriedades volumétricas e mecânicas. Além disso foram realizados análises físicas e reológicas do CAP puro e modificado. De acordo com os resultados obtidos nesta pesquisa pode -se inferir que o PET micronizado pós consumo corresponde a um polímero melhorador das propriedades reológicas do CAP 50/70, em termos de rigidez, proporcionado a mistura asfáltica um incremento no comportamento mecânico a luz dos ensaios de Resistência à Tração por Compressão Diametral, Módulo de Resiliência, Resistência por Umidade Induzida, Flow Number e Ruptura por Fadiga. É possível aceitar que “o resíduo do PET micronizado, no teor de 5% pode ser utilizado como agente modificador do CAP e, que o mesmo e capaz de promover ganhos nas Propriedades Mecânicas de Revestimentos Asfálticos.
The addition of polyethylene terephthalate (PET) waste in binder, crushed into particles whose diameter is between 0.074 and 0.6 mm, may be a viable alternative technique to improve the mechanical and rheological properties of asphalt mixtures . This addition is intended to provide a lower susceptibility of fatigue in asphalt mixtures and consequently improve the durability of asphalt mixtures in regions with tropical climate and high temperatures. This work has the objective the incorporation of an additive in binder. It was add in proportions of 4% 5% and 6% relative to the weight of the optimum binder content and it was measured volumetric and mechanical properties of asphalt mixtures. Also performed were physical and rheological analysis of pure and modified binder. According to the results obtained in this study can be inferred that the micronized PET improve the performance of binder 50/70. The addition of PET provided an increase in the mechanical behavior in the Indirect Tensile Strength, Resilient Modulus, Moisture susceptibility, Flow Number and Fatigue life. It is possible to accept that the use of 5% micronized PET waste may be used as modifying agent of binder, and that it improve mechanical properties of asphalt mixtures.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Sant, ana Carla Simone. « Especiação de compostos de enxofre, níquel e vanádio em cimento asfáltico de petróleo (CAP) e sua relação com os processos de envelhecimento ». Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/4277.

Texte intégral

Résumé :

The speciation of sulfur compounds in CAP is very important, considering that these compounds are responsible for oxidation processes in asphalt binders, modifying their chemical and physical characteristics. The aim of this work was focused on chemical speciation of sulfur compounds in virgin and aged CAP samples (methods RTFOT, RTFOT/PAV, and RTFOT/SUNTEST) and their maltenic fractions. The separation of sulfur classes were carried out using the method developed by Payzant, which employs specific oxidation reactions and chromatographic separation on silica columns. The studied sulfur compound classes were the following: aromatic/saturated sulfur, aliphatic sulfides, thiophenes and sulfoxides. For this purpose, 6 samples were comparatively analyzed in virgin and aged CAP regarding the distribution of sulfur compounds in the three obtained fractions, where total sulfur was determined in order to observe the compounds behavior in the fractions after different aging processes. After speciation of the compounds, it was observed that the aging process occurs with structural changes in CAP, which involved the break and opening of thiophenic rings and the consequent formation of new S-compounds of high molecular weight. Sulfur compounds in form of sulfoxides increased after aging by RTFOT and RTFOT/PAV. Nickerl and vanadium were also analyzed in the studied samples by GFAAS (maltenic and asphaltenic fractions), since these species are involved in the aging process in CAP. The distribution of Ni and V in asphaltenic and maltenic fractions showed a diminishing of contents of the metals due to the lost by volatilization as metalloporphyrins. Correlating the chemical and physical changes observed in CAP, the variation in viscoelastic properties (G*/sin) may be a reflect of alterations in thiophenic fractions; additionally, variations in the penetration point may be related with the variation in asphaltenes and sulfur compounds of acid/basic characters, what may also be related to the viscoelastic changes in CAP. Based on the obtained results, this work aimed to answer 6 main guiding questions of the thesis: (1) which transformations occur in the speciation of sulfur compounds with the CAP aging after short-term, long-term and UV radiation processes?; (2) what is the major class of sulfur compounds in CAP and how it changes with the aging process?; (3) which transformations occur in the metals nickel and vanadium with CAP aging after short-term, long-term and UV radiation processes?; (4) the forced aging processes for CAP (RTFOT, PAV and SUNTEST) lead to different chemical transformations in asphaltenes and maltenes?; (5) what are the correlations existing between the chemical and physical changes in CAP, from the chemical speciation and rheology after aging process?; (6) is it possible to establish some chemical reactivity order for CAP based on the chemical speciation and rheology after aging process?
A especiação de compostos sulfurados em CAP é de grande importância, uma vez que alguns desses compostos são responsáveis pela oxidação de ligantes asfálticos, modificando suas características químicas e físicas. Este trabalho tem como foco a especiação química de classes majoritárias de compostos sulfurados em amostras de CAP virgem e envelhecidas (métodos RTFOT, RTFOT+PAV e RTFOT+SUNTEST) e suas respectivas frações maltênicas. A especiação das classes sulfuradas foi realizada pelo método adaptado de Payzant empregando reações de oxidação específicas e separações cromatográficas por adsorção em sílica. Os teores de sulfóxidos foram obtidos por FTIR, utilizando-se como padrão de sulfóxidos uma solução de referência de tetrametileno sulfóxido (TMSO) em diclorometano. As classes de compostos estudadas foram: sulfurados aromáticos/saturados, tiofenos, sulfetos alifáticos e sulfóxidos. Para isso, foram analisadas comparativamente 6 amostras de CAP virgem e envelhecidas em relação à distribuição dos compostos sulfurados nas três frações obtidas, onde foram analisados os teores de enxofre total a fim de se observar o comportamento dos compostos nessas frações nos diferentes processos de envelhecimento. Com base nesses resultados, observa-se que no processo de envelhecimento ocorrem mudanças estruturais envolvendo quebras de ligações em anéis tiofênicos e formação de novas classes de compostos sulfurados de maior peso molecular. Os compostos de enxofre na forma de sulfóxidos apresentaram um aumento decorrente dos processos de envelhecimento para os envelhecimentos RTFOT e RTFOT/PAV. Também foram analisados os teores de Níquel e Vanádio nas diferentes amostras, em suas frações maltênicas e asfaltênicas por GFAAS, já que estes metais são envolvidos como coadjuvantes no processo de envelhecimento dos CAPs. A distribuição dos metais de Ni e V nas frações asfaltênicas e maltênicas sofreu uma diminuição nos teores destes metais decorrente das perdas por volatilização na forma de metaloporfirinas. Correlacionando-se as alterações químicas e físicas observadas em CAP, as variações nas propriedades viscoelásticas (G*/sin) podem ser um reflexo das alterações que ocorrem nas frações tiofênicas; além disso, a variação no aumento da penetração pode estar relacionada com a variação do teor de asfaltenos e de compostos de caráter e básico, que também podem ser relacionados com as mudanças viscoelásticas dos CAPs. Com base nos resultados obtidos, esse trabalho buscou responder a 6 perguntas principais e norteadoras da tese apresentada: (1) que transformações ocorrem na especiação de compostos de enxofre com o envelhecimento de CAP em curto prazo, longo prazo e sob ação da radiação UV?; (2) qual a classe majoritária de compostos de enxofre em CAP e como esta se altera com o envelhecimento?; (3) que transformações ocorrem nos metais níquel e vanádio com o envelhecimento de CAP em curto prazo, longo prazo e sob ação da radiação UV?; (4) os processos de envelhecimento forçado de CAP (RTFOT, PAV e SUNTEST) conduzem a transformações químicas diferentes em asfaltenos e maltenos?; (5) quais as correlações existentes entre as transformações químicas e físicas em CAP, a partir da especiação química e da reologia após o envelhecimento?; (6) é possível estabelecer alguma ordem de reatividade química para o CAP com base na especiação química e na reologia após o envelhecimento?

Styles APA, Harvard, Vancouver, ISO, etc.

31

Claussen, Luís Evandro. « Compostos sulfurados em asfaltos : influência do processo de envelhecimento na composição das frações maltênicas e asfaltênicas ». Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/10552.

Texte intégral

Résumé :

The behavior of sulfur compounds in asphalt cements can be studied in a more comprehensive way through the separation of maltenes and asphaltenes and their respective fractions. Thus, the ASTM D4124 method was applied for the separation of maltenes and asphaltenes in acidic, basic and neutral fractions of súlfur compounds. Herein, it could be observed that the sulfur heteroatom appears in higher levels as a less reactive fraction (neutral compounds) for virgin asphalts. The aging process lead to an increase of at least 20% for the polar fractions of sulfur, which is related to here to acidic and basic sulfur compounds. From this speciation results, a classification of the asphalt samples can be proposed taking into account the calculated reactivity in terms of polar (acidic/basic) and neutral compounds. These results permit to infer that a higher content of asphaltenes does not necessarily imply in a higher reactivity of the asphaltic binder. So the presence of specific functional groups related to these heteroatoms (e.g. sulfur) may be definitive for a greater or lesser susceptibility of the binder to the aging processes.
O estudo do comportamento de compostos sulfurados no cimento asfáltico de petróleo (CAP) pode ser melhor entendido através da separação em maltenos, asfaltenos e suas respectivas frações. Com esta finalidade, foi utilizado a ASTM D4124 para o fracionamento de amostras de asfalto em maltenos e asfaltenos. Por conseguinte, maltenos e asfaltenos foram fracionados em suas respectivas frações ácida, básica e neutra para a especiação dos compostos sulfurados. Em se tratando de maltenos e asfaltenos, observou-se que o enxofre aparece em maior quantidade na fração menos reativa (fração neutra) para amostras virgens, sendo que com o processo envelhecimento leva a um aumento (>20%) da fração mais polar do asfalto relacionada a compostos sulfurados ácidos e básicos. A partir dessa especiação, uma classificação das amostras estudadas foi proposta levando em consideração a reatividade calculada em termos de compostos polares e neutros. Estes resultados permitem inferir que um maior teor de asfaltenos não implica necessariamente em uma maior reatividade do ligante asfáltico. A presença de grupos funcionais específicos relacionados a seus heteroátomos (a exemplo do enxofre) deve ser definitiva para uma maior ou menor suscetibilidade do ligante ao envelhecimento.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Gusmão, Claudia Betine. « Evolução temporal da resistencia mecanica em laboratorio, de misturas simulando a reciclagem de pavimento asfaltico com adição de cimento portland ». [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257804.

Texte intégral

Résumé :

Orientador: João Virgilio Merighi
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
Made available in DSpace on 2018-08-12T12:23:13Z (GMT). No. of bitstreams: 1 Gusmao_ClaudiaBetine_M.pdf: 2591416 bytes, checksum: b106affc2585283a589b10f376f83035 (MD5) Previous issue date: 2008
Resumo: O presente trabalho visa estudar o processo de reciclagem de pavimento asfaltico com cimento Portland, atraves da analise de metodo de reciclagem, equipamentos utilizados, procedimentos empregados em campo, alem do estudo das vantagens e desvantagens do uso da reciclagem em pavimentos asfalticos. O trabalho trata ainda de uma forma detalhada o pavimento asfaltico com adicao de cimento Portland, atraves de ensaios tecnologicos simulando em laboratorio, para diferentes dosagens o comportamento mecanico em funcao do tempo do material obtido em campo.
Abstract: This work studies the process of asphalted pavement recycling with cement Portland additive through the analysis of recycling method, equipments and procedures used in the field, in addition to studying the advantages and disadvantages of the use of recycling in asphalted pavement. The work also approaches in detail the recycled asphalt pavement with Portland cement additive, through technological tests through laboratory simulation, to different dosage and the analysis of mechanical behavior through time of that material obtained in field.
Mestrado
Transportes
Mestre em Engenharia Civil

Styles APA, Harvard, Vancouver, ISO, etc.

33

Moreira, AntÃnio AurÃlio Gomes. « Propriedades ReolÃgicas e ResistÃncia a OxidaÃÃo de Cimento AsfÃltico de PetrÃleo (CAP) Modificado com Cardanol ». Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12145.

Texte intégral

Résumé :

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior
Neste trabalho, um derivado fenÃlico extraÃdo do lÃquido da casca da castanha de caju (LCC), fonte natural e renovÃvel, foi utilizado como aditivo modificador de cimento asfÃltico de petrÃleo (CAP). FraÃÃes extraÃdas por diferentes mÃtodos (I, II e III) foram analisadas por cromatografia lÃquida de alta eficiÃncia (HPLC) e por espectroscopia no infravermelho, tendo sido identificadas como cardanol. Os CAP modificados por cardanol (I) foram comparados ao CAP modificado por LCC e estireno-butadieno-estireno (SBS), sendo avaliadas suas propriedades reolÃgicas antes e apÃs envelhecimento simulado. O LCC e o cardanol (I) atuaram de forma semelhante, aumentando os valores de penetraÃÃo e reduzindo o ponto de amolecimento, a viscosidade, a temperatura de usinagem e compactaÃÃo (TUC), e a susceptibilidade tÃrmica do ligante. Os parÃmetros reolÃgicos, obtidos em reÃmetro de cisalhamento dinÃmico (DSR), indicaram que LCC e cardanol (I) tornaram o CAP mais susceptÃvel Ã deformaÃÃo permanente, no entanto, nÃo houve alteraÃÃo do desempenho do CAP a baixas temperaturas. Foi verificado que o cardanol pode atuar como agente compatibilizante de CAP modificado com SBS, tal como os Ãleos aromÃticos comerciais. Em relaÃÃo ao CAP original, o CAP com SBS apresentou diminuiÃÃo na penetraÃÃo e na susceptibilidade tÃrmica, e aumento do ponto de amolecimento e da viscosidade. Os parÃmetros reolÃgicos (G*, δ) indicaram que o CAP com SBS foi mais resistente Ã deformaÃÃo permanente. O efeito dos aditivos em relaÃÃo ao grau de desempenho (PG), a altas temperaturas, para os CAP modificados foi CAP/SBS > CAP/cardanol ≥ CAP/LCC. O PG, a baixas temperaturas, foi superior para CAP/SBS, indicando que este pode ser aplicado em regiÃes de clima frio. A resistÃncia Ã decomposiÃÃo tÃrmica, observada por termogravimetria (TGA), foi semelhante para todas as amostras. As curvas de calorimetria exploratÃria diferencial (DSC) mostraram que todas as amostras possuem baixo teor de fraÃÃes cristalizÃveis e que o CAP modificado com cardanol apresenta maior resistÃncia ao trincamento tÃrmico. O efeito de cardanol como potencial antioxidante foi avaliado apÃs o envelhecimento em estufa RTFOT, e por espectroscopia no infravermelho (FTIR). Os resultados indicaram que o cardanol foi Ãtil para atuar como aditivo redutor do envelhecimento do CAP. Na preparaÃÃo de corpos de prova de misturas CAP/cardanol e agregado constatou-se uma economia no teor de ligante requerido, comparando-se com o CAP sem aditivo. No ensaio Lottman modificado, foi verificado que o cardanol agiu como melhorador da adesividade (AMA) entre ligante e agregado, conforme medida da resistÃncia Ã traÃÃo (RRT) acima de 80%, e acima do valor encontrado para o CAP virgem.
In this work, phenolics from renewable and natural sources extracted from cashew nut shell liquid (CNSL) were used as petroleum asphalt cement (PAC) modifiers additives. Fractions extracted by different methods (I, II and III) were analyzed by High Performance Liquid chromatography (HPLC) and Infrared Spectroscopy (FTIR) and were identified as cardanol. The PAC modified by cardanol I was compared to PAC modified with CNSL and styrene-butadiene-estyrene (SBS) by measuring its rheological properties before and after an aging simulation evaluation. CNSL and cardanol I showed, similarly, increasing values of penetration and decreasing the soft point, the viscosity, the mixing and compaction temperature and the thermal susceptibility. Regarding the rheological parameters obtained by dynamic shear rheometer (DSR), it was observed that PAC/CNSL and PAC/cardanol became more susceptible to rutting. It was verified that cardanol acted as a compatibility agent in PAC modified with SBS in a similar way as for commercial aromatics oils. On the other hand, PAC modified with SBS showed decreasing on penetration values and on thermal susceptibility, as well as increasing soft point and viscosity values. PAC modified with SBS was more resistant to rutting as observed by its rheological parameters (G*, δ). The performance grade (PG) in high temperatures was lower for PAC/cardanol I and PAC/CNSL then for PAC modified with SBS, confirming the conclusions obtained by analysis of the rheological parameters. The PG value, in low temperatures, was greater for PAC modified with SBS then those for the other modified PAC, indicating that this mixture can be used in cold climates. For PAC modified with cardanol I and with CNSL, there was no change performance in low temperatures. The resistance to thermal degradation verified by thermogravimetry (TGA) was similar for all samples. The differential scanning calorimetry (DSC) showed that all samples have low content of crystallizable fractions and PAC modified by cardanol has a higher thermal crack resistance. Simulated oxidative ageing showed that cardanol acted as antioxidants. For the dosage of PAC modified with cardanol II, it was observed an economy in the content of used binder compared to PAC without any additive. In the Lottman modified test it was verified that cardanol II acted as an anti-stripping agent (ASA) between the binder and aggregates because it was found a tensile strength ratio (TSR) higher than 80% and larger than the value found for unmodified PAC.

Styles APA, Harvard, Vancouver, ISO, etc.

34

Lutonský, Filip. « Asfaltocementový beton ». Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226042.

Texte intégral

Résumé :

The thesis is aimed at deepening knowledge about the design and use of open-graded asphalt concrete filled with a special cement grout. The first part is the issue discussed theoretically with reference to the real possibility of practical application, a description of the various manufacturers and their patented technologies. The second part of this work is devoted to assess the resistance of this technology to chemical de-icing agents.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Rocha, Mirella Talitha. « Estudo laboratorial de um solo tropical granular estabilizado quimicamente para fins de pavimentação ». Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/8843.

Texte intégral

Résumé :

Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2018-08-30T15:40:26Z No. of bitstreams: 2 Dissertação - Mirella Talitha Rocha - 2016.pdf: 5610966 bytes, checksum: a480f957a8e5ca103e387a6d96cdc48e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-09-03T11:46:56Z (GMT) No. of bitstreams: 2 Dissertação - Mirella Talitha Rocha - 2016.pdf: 5610966 bytes, checksum: a480f957a8e5ca103e387a6d96cdc48e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Made available in DSpace on 2018-09-03T11:46:56Z (GMT). No. of bitstreams: 2 Dissertação - Mirella Talitha Rocha - 2016.pdf: 5610966 bytes, checksum: a480f957a8e5ca103e387a6d96cdc48e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-08-18
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The use of alternative materials as subbases and bases stabilization is being increasingly in asphalt pavements, especially in areas with lack of granular materials. The chemical stabilization using additives such as Portland cement and hydrated lime is used since antiquity, with the aim of improving the geotechnical characteristics of natural materials. The treated soils exhibit complex behavior, influenced by several factors such as chemical reactions, soil types, added amount of stabilizing, moisture content and the time and type of curing. Generally, the procedure for determining the minimum lime or cement content to be added to the mixture refers to the initial estimate and attempts the standard recommendations to meet the parameters of mechanical tests, in order to define a minimum additive amount present resistance compatible with the paving design. The focus of this research was initially to analyze the dosage employed in the base layer of the GO-080 highway, in the stretch between Neropolis-GO and the BR-153 where the pavement structure consists of 20 cm thick granulometrically stabilized subbase, gravel laterite base with 20 cm thick and stabilized with 20% sand, 2% Portland cement (PC II-Z-32) and asphalt concrete surface with 5 cm thick. In addition, the aim was also to study the mechanical properties of natural gravel and their behavior when mixed with three levels (2%, 4% and 6%) of cement and hydrated lime. Therefore, laboratory tests for soil characterization, compaction tests on intermediate Proctor energy, determination of expansion and California Bearing Ratio, unconfined compression and resilient modulus of the molded mixture at the optimum moisture for three times cure (0, 7 and 28 days) were carried out. The resilient moduli results were evaluated by numerical analysis using KENLAYER software. To complement the analysis of strength parameters, diffraction X-ray and scanning electron microscopy tests were performed. The results show that for the studied soil, the chemical stabilization with lime contributed little to the increase of strength parameters, but the use of cement showed greater potential use. Differences on behavior observed in unconfined compression tests and dynamic triaxial were explained by changes that occur in the microstructure during the stabilization process. Finally, it is clear that the tropical soil stabilization process is complex, with over current mechanical tests, such as dynamic triaxial, and unconventional parameters for pavement soil analysis, such as water/cement ratio and porosity, should be analyzes incorporated in order to obtain more consistent results.
O emprego de materiais alternativos em sub-bases e bases está sendo cada vez mais frequente em pavimentos asfálticos, principalmente em regiões com ausência de materiais granulares. A estabilização química utilizando aditivos como o cimento Portland e a cal hidratada é empregada desde a antiguidade, com o objetivo de melhorar as características geotécnicas dos materiais naturais. Os solos tratados apresentam comportamento complexo, influenciados por diversos fatores como reações químicas, tipos de solo, quantidade adicionada de estabilizante, teor de umidade e o tempo e tipo de cura. Geralmente, o procedimento para determinar o teor mínimo de cal ou cimento a ser adicionado à mistura refere-se a uma estimativa inicial e segue as recomendações normativas para atender os parâmetros de ensaios mecânicos, de forma a definir um valor mínimo de aditivo que apresente resistência compatível com o projeto do pavimento. O foco desta pesquisa consistiu, inicialmente, em analisar a dosagem empregada na camada de base da rodovia GO-080, no trecho entre Nerópolis-GO e o entrocamento da BR-153, onde a estrutura do pavimento é constituída por sub-base estabilizada granulometricamente com 20 cm de espessura, base de cascalho laterítico com 20 cm de espessura e estabilizada com 20% de areia e 2% de cimento Portland (CP II-Z-32) e revestimento em concreto asfáltico de 5 cm de espessura. Além disso, objetivou-se, ainda, estudar as propriedades mecânicas do cascalho sem mistura e seu comportamento ao ser misturado com três teores (2%, 4% e 6%) de cimento e de cal hidratada. Para tanto, foram realizados ensaios laboratoriais para a caracterização do solo, ensaios de compactação na energia Proctor intermediária, determinação da expansão e do Índice de Suporte Califórnia, da resistência à compressão simples e módulo de resiliência das misturas moldadas na umidade ótima, para três tempos de cura (0, 7 e 28 dias). Para interpretação dos resultados em termos de módulo de resiliência, foram realizadas análises numéricas com o programa KENLAYER. Para complementação das análises dos parâmetros de resistência, foram realizados ensaios de difração de raios-X e microscopia eletrônica de varredura. Os resultados obtidos mostram que para o solo em questão, a estabilização química com cal pouco contribuiu com o aumento dos parâmetros de resistência. Já o uso do cimento apresentou maior potencial de utilização. As diferenças de comportamento observadas nos ensaios de compressão simples e triaxial dinâmico foram explicadas por mudanças que acontecem na microestrutura durante o processo de estabilização. Por fim, conclui-se que o processo de estabilização de solos tropicais é complexo, sendo que ensaios mecânicos mais atuais, como o triaxial dinâmico, e parâmetros não convencionais para análise de solos para pavimentação, como a relação água/cimento e porosidade, devem ser incorporados nas análises para a obtenção de resultados mais consistentes.

Styles APA, Harvard, Vancouver, ISO, etc.

36

Siripun, Komsun. « Characterisations of base course materials in Western Australia pavements ». Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/960.

Texte intégral

Résumé :

Western Australia (WA) has a road network of approximately 177,700 km, including a 17,800 km stage highway system (Main Roads Western Australia 2009). This infrastructure supports a population of only about two million, and road funds always have to be carefully considered when allocated to highway authorities or other organisations. Pavement design is a process intended to find the most economical combination of suitable materials and layer thicknesses for construction. The pavement must have a carefully-specified unbound granular base to further reduce construction costs, and must be surfaced with an approximately 30 mm asphalt surface in WA. High quality aggregates are therefore required for the base course layer of a pavement because of its proximity to the road surface. Traffic loads on the road surface result in high stress levels on the base course layer. Consequently, Hydrated Cement Treated Crushed Rock Base (HCTCRB) was developed.Current pavement analysis and design in WA is thought to be sub-standard. A number of highways and roads in WA are exhibiting extensive surface damage as a result of the increasing numbers of vehicles in use. Since pavement analysis and design in WA relies predominantly on empirical design, experience and basic experimentation, explanations for the damage occurring under present conditions are difficult to determine and assess.In most areas of the USA and Europe, pavement design and analysis has entered a new era with mechanistic design replacing empirical design. Unlike the empirical approach, a mechanistic approach seeks to explain pavement characteristics under real operational pavement conditions (loads, material properties of the pavement structure, and environments), and is based on design parameters derived from sophisticated tests which can simulate real pavement conditions in the test protocol (WSDOT 2008). The mechanistic approach to pavement design produces more relevant and useful results and these procedures, along with linear elastic analysis, were introduced into Australia by the 1987 NAASRA Guide (NAASRA 1987), of which the revised version became the AUSTROADS Guide (Austroads 2004) to the Structural Design of Road Pavements. AUSTROADS published a National Pavement Research Strategy which has been the keystone for the national co-ordination of pavement research, both within government and industry.Adaptation of the Cement Modified Crushed Rock Base concept has brought about an excellent road base material for Western Australia (WA) by the addition of a small amount of cement (1-2% by mass) to a fresh crushed rock material. The mix is stockpiled for a hydration period, and after that retreated before construction, unlike the traditional concept for cement modified/stabilised materials. This material is usually called Hydrated Cement Treated Crushed Rock Base (HCTCRB), a name established by Western Australia Mainroads (MRWA). More than 250,000 tonnes of HCTCRB has been used at a cost in excess of $10 million over the last eight years.Recently, as a result of early damage on new highways and roads in WA, MRWA and its contractors and organisations have attempted to identify the cause of this damage. HCTCRB, which is currently the best option for base course materials in WA, and Crushed Road Base (CRB), the original road base material, need to be re-examined to overcome the shortcomings in terms of analysis, design, and application. All of the factors involved in HCTCRB and CRB for today’s pavement conditions have been extrapolated far beyond the bounds of the original data, and current experience shows these require detailed re-investigation.This research aimed to study on the characteristics of CRB and HCTCRB and to determine reliable mathematical material models for the improvement in the current pavement design criteria. This study also investigated both elastic and plastic behaviour of CRB and HCTCRB. In this study, there were two relevant factors of both pavement materials which are considered in order to fulfil a lack of understanding in realistic conditions in pavements of the current pavement design. 1) The material strength which indicates the limitation and stability of pavement materials under traffic loads. This study employed the Mohr-Coulomb failure envelope to define the limitation of material implementation and also brought in the resilient modulus of materials to be the significant input parameter for multilayer finite element analysis to characterise the stress distribution in pavements. 2) The pavement failure of long term road performance relating to the design life of pavements. The permanent deformation behaviour and the shakedown concept under various stress conditions, simulated from repeated load triaxial (RLT) tests, therefore, were taken into account to investigate such long-term performance of HCTCRB and CRB and then the implementation of the findings was made to the current pavement analysis and design. Furthermore, more reliable mathematic models of base course materials for short and long term performance during their service life were established based on the laboratory test results of this study.

Styles APA, Harvard, Vancouver, ISO, etc.

37

Hruška, Lukáš. « Asfaltocementový beton ». Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225561.

Texte intégral

Résumé :

Aim of this thesis is the usage of the open-graded asphalt concrete filled with a special cement grout in the road structures. Thesis defines the main concrete properties and explains related legislation and norms that apply. In addition, laboratory design of asfalt mixtures and a tree kind mortal filler and possibilities of mortal filler pigmentation are dealth with. Finally, thesis evaluates the results from various laboratory tests that were performed on the specimens made from final mixtures.

Styles APA, Harvard, Vancouver, ISO, etc.

38

Roper, Matthew B. « Evaluation of Laboratory Durability Tests for Stabilized Aggregate Base Materials ». BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/902.

Texte intégral

Résumé :

The Portland Cement Association commissioned a research project at Brigham Young University to compare selected laboratory durability tests available for assessing stabilized aggregate base materials. The laboratory research associated with this project involved two granular base materials, three stabilizers at three concentration levels each, and three durability tests in a full-factorial experimental design. The granular base materials consisted of an aggregate-reclaimed asphalt pavement blend obtained from Interstate 84 (I-84) and a crushed limestone obtained from U.S. Highway 91 (US-91), while the three stabilizer types included Class C fly ash, lime-fly ash, and Type I/II Portland cement. Specimens were tested for durability using the freeze-thaw test, the vacuum saturation test, and the tube suction test. Analyses of the test results indicated that the unconfined compressive strength (UCS) and retained UCS were higher for specimens tested in freeze-thaw cycling than the corresponding values associated with vacuum saturation testing. This observation suggests that the vacuum saturation test is more severe than the freeze-thaw test for materials similar to those evaluated in this research. The analyses also indicated that the I-84 material retained more strength during freeze-thaw cycling and vacuum saturation and exhibited lower final dielectric values during tube suction testing than the US-91 material. Although the I-84 material performed better than the US-91 material, the I-84 material required higher stabilizer concentrations to reach the target 7-day UCS values specified in this research. After freeze-thaw testing, the Class C fly-treated specimens were significantly stronger than both lime-fly ash- and cement-treated specimens. In the vacuum saturation test, none of the three stabilizer types were significantly different from each other with respect to either UCS or retained UCS. Dielectric values measured during tube suction testing were lowest for cement-treated specimens, indicating that cement performed better than other stabilizers in reducing the moisture/frost susceptibility of the treated materials. The results also show that, as the stabilizer concentration level increased from low to high, specimens performed better in nearly all cases. A strong correlation was identified between UCS after the freeze-thaw test and UCS after the vacuum saturation test, while very weak correlations were observed between the final dielectric value after tube suction testing and all other response variables. Differences in variability between test results were determined to be statistically insignificant. Engineers interested in specifying a comparatively severe laboratory durability test should consider vacuum saturation testing for specimens treated with stabilizers similar to those evaluated in this research. The vacuum saturation test is superior to both the freeze-thaw and tube suction tests because of the shorter duration and lack of a need for daily specimen monitoring. Although the Class C fly ash used in this research performed well, further investigation of various sources of Class C fly ash is recommended because of the variability inherent in that material. Similar research should be performed on subgrade soils, which are also routinely stabilized in pavement construction. Research related to long-term field performance of stabilized materials should be conducted to develop appropriate thresholds for laboratory UCS values in conjunction with vacuum saturation testing.

Styles APA, Harvard, Vancouver, ISO, etc.

39

Alencar, Ana Ellen Valentim de. « Estudo das propriedades do cimento asfÃltico de petrÃleo modificado por copolÃmero de etileno e acetato de vinila(eva) ». Universidade Federal do CearÃ, 2005. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1439.

Texte intégral

Résumé :

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
Cimento AsfÃltico de PetrÃleo (CAP), caracterizado como CAP 50/60, oriundo do Campo Fazenda Alegre, no estado do EspÃrito Santo, foi modificado por adiÃÃo de CopolÃmero de Etileno e Acetato de Vinila (EVA). Na modificaÃÃo foram incorporadas amostras do copolÃmero EVA puro e proveniente do resÃduo da indÃstria de calÃados (EVAR). Os CAPS, polÃmeros e CAPS modificados, foram inicialmente caracterizados por espectroscopia no infravermelho (FTIR) e ressonÃncia magnÃtica nuclear (RMN). AnÃlise tÃrmica, como a termogravimetria (TG) e caloria exploratÃria diferencial (DSC), foi utilizada para o estudo da decomposiÃÃo tÃrmica, bem como para avaliar a estabilidade termoxidativa das amostras. Testes empÃricos como penetraÃÃo, ponto de amolecimento, susceptibilidade tÃrmica e retorno elÃstico, alÃm de viscosidade, tambÃm foram realizados para caracterizaÃÃo dos materiais. Os resultados indicaram que CAPS modificados apresentaram maior estabilidade em atmosfera oxidativa do que em atmosfera inerte. A anÃlise das curvas DSC revelou que os CAPS modificados mostraram-se mais resistentes Ã trincas tÃrmicas, quando submetidos a temperaturas mais baixas, que o CAP convencional. Os CAPS modificados foram mais resistentes Ã decomposiÃÃo oxidativa, quando foram submetidos ao envelhecimento simulado. A viscosidade do ligante modificado por adiÃÃo do polÃmero foi aumentada em relaÃÃo ao ligante puro. Diferentemente do CAP convencional, o CAP modificado por EVAR apresentou comportamento nÃo Newtoniano. Os ensaios empÃricos, relativos Ã penetraÃÃo, ponto de amolecimento, susceptibilidade tÃrmica e retorno elÃstico, mostraram que os CAPS modificados com EVAR, tiveram uma melhoria nas suas propriedades fÃsicas, em relaÃÃo aos CAPS nÃo modificados.
The Petroleum Asphaltic Cement characterized as CAP 50/60, produced at the state of EspÃrito Santo (Fazenda Alegre), was modified by addition of copolymers of ethylene vinyl acetate (EVA) and EVA from the footwearâs industry residue (EVAR). The original and modified CAPS were characterized by infrared spectroscopy (FTIR) and nuclear magnetic resonance (RMN). Thermal analysis,as thermogravimetry (TG) and differential scanning calorimetry (DSC), was used to evaluate the thermal stability of the samples. The characterization was also performed with empirical tests such as penetration, softening point, elastic recovery and viscosity. The main results indicated that polymer modified CAPS presented larger thermal stability in oxidative atmosphere than in inert atmosphere. The analysis of DSC curves revealed that modified CAPS, when submitted to lower temperatures, were more resistant to the thermal cracks than conventional CAP. Also modified CAPS showed to be more resistant to the thermal oxidative decomposition, when submitted to a simulated aging process. The viscosity of the polymer modified binder was increased in relation to the original binder. Polymer modified CAP EVAR presented non-Newtonian behavior, whereas Newtonian behavior was observed for unmodified CAP. It was observed that modifying the asphalt binder with a copolymer EVAR leads to an improvement in the physical properties in relation to the penetration, softening point, thermal susceptibility and elastic recovery

Styles APA, Harvard, Vancouver, ISO, etc.

40

ADHIKARI, THAM. « QUALITY AND DURABILITY OF RUBBERIZED ASPHALT CEMENT AND WARM RUBBERIZED ASPHALT CEMENT ». Thesis, 2013. http://hdl.handle.net/1974/7921.

Texte intégral

Résumé :

This thesis discusses and documents findings from an investigation of performance-based testing of asphalt cement (AC), warm mixed asphalt cement, asphalt rubber (AR), and warm asphalt rubber. A number of control, warm, and asphalt rubber binders from Ontario construction contracts were investigated for their compliance with conventional Superpave® test methods such as rolling thin film (RTFO), pressure aging vessel (PAV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR), as well as additional specification tests such as extended BBR and double edge notched tension test. The quality and durability of those binders were determined. Quality means the ability of asphalt binder to reach a set of specific properties whereas durability is the measure of how well asphalt retains its original characteristics when exposed to normal weathering and aging process. One warm AC and two field-blended asphalt rubber samples showed high levels of physical hardening which can lead to premature and early cracking. The warm asphalt cement lost 8 °C when stored isothermally for three days at low temperatures according to Ontario’s extended bending beam rheometer (BBR) protocol (LS-308). The two asphalt rubber samples lost 10 °C and 12 °C following the same conditioning. Many of the studied asphalt samples showed deficient strain tolerance as measured in Ontario’s double-edge-notched tension (DENT) test (LS-299). In a study of warm rubberized asphalt cement with improved properties, a number of compositions were prepared with soft Cold Lake AC and a small quantity of naphthenic oil. These binders showed little chemical and physical hardening and reasonable critical crack tip opening displacements (CTOD). Strain tolerance was much improved by co-blending with a high vinyl type styrene-butadiene-styrene (SBS) polymer and a small amount of sulfur.
Thesis (Master, Chemistry) -- Queen's University, 2013-04-24 22:54:20.07

Styles APA, Harvard, Vancouver, ISO, etc.

41

Shih, Jung-Chieh, et 石榮傑. « Study on Cement Asphalt Paste Applied to Permeable Asphalt Pavement ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/91509953150985635623.

Texte intégral

Résumé :

碩士
國立臺灣科技大學
營建工程系
93
The study focuses on using different cement/asphalt ratio (C/A ratio), and cement asphalt paste to be binder. The decision of aggregate gradation is depending on laboratory compaction method(by ASTM D698), maximum unit weight, and expect void in coarse aggregate. The mixture design method is following ASTM D1559 to evaluate the practicability for using cement asphalt paste applied to permeable asphalt pavement. The major finding based on result of our experimental are summarized as follows: The mechanic properties such as Marshall stability, indirect tension and direct shear strength increase with age and cement-asphalt ratio. Because the temperature susceptibility of cement asphalt paste is lower than traditional modified asphalt. Therefore, the mechanical properties are better than normal permeable asphalt pavement. The result of immersion compression test (AASHTO T165) demonstrated the residual strength index excess 100%, the mainly reason is test specimen on the condition of 60 ℃ will accelerating the hydration of cement. Therefore, the immersion compression strength of semi-rigid permeable asphalt pavement is better than normal permeable asphalt pavement obviously. Due to the results of Cantabria abrasion test showed that the flexibility and toughness of normal permeable asphalt pavement is better than semi-rigid permeable asphalt pavement. The permeability coefficient of semi-rigid permeable asphalt pavement and normal permeable pavement are both higher than 10-2 cm/sec, the result demonstrated that have good permeability. The result of wheel tracking test indicate the dynamic stability of semi-rigid permeable pavement is better than normal permeable asphalt pavement. Therefore, apply cement asphalt paste to permeable pavement have practicability.

Styles APA, Harvard, Vancouver, ISO, etc.

42

Hung, Guo-Neng, et 洪國能. « Performance Evaluation on Porous Asphalt Concrete between Asphalt Rubber Modifier and AR-80 Asphalt Cement ». Thesis, 2008. http://ndltd.ncl.edu.tw/handle/34337701436802422999.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

43

Su, Yu-chia, et 蘇郁嘉. « Study on Cement Asphalt Paste with Nanomaterials Applied to Permeable Asphalt Pavement ». Thesis, 2006. http://ndltd.ncl.edu.tw/handle/9krd28.

Texte intégral

Résumé :

碩士
國立臺灣科技大學
營建工程系
94
The study focuses on using nano-silica fume in place of cement to mix cement asphalt paste to be binder. The decision of aggregate gradation is depending on laboratory compaction method(by ASTM D698).The mixture design method is following ASTM D1559 for using cement asphalt paste with aggregate to mix Semi-Rigid Permeable Asphalt Concrete(SRPAC). Then experiments with mechanical properties, permeability and durability, and evaluating the practicability for using nano-silica fume applied to permeable asphalt pavement. The research results about mechanical properties that SRPAC with silica fume is better than SRPAC without silica fume and normal permeable asphalt pavement. About results of durability tests, Cantabria abrasion test show that the flexibility and toughness of the normal permeable asphalt pavement is better than SRPAC with silica fume, but the results of wheel tracking test show that the dynamic stability of SRPAC with silica fume is better. The results of immersion compression test(AASHTO T165) demonstrated the residual strength index excess 100% show that have good performance to resist to peel. About permeability performance, permeability coefficient of SRPAC with silica fume is higher than 0.01cm/sec, the result demonstrated that have good permeability performance. Therefore, cement asphalt paste with nano-silica fume can improve properties of Semi-Rigid Permeable Asphalt Concrete.

Styles APA, Harvard, Vancouver, ISO, etc.

44

Teng, Yu-Cheng, et 鄧宇承. « Study on the Properties of Cement Asphalt-Emulsion Mortar ». Thesis, 2008. http://ndltd.ncl.edu.tw/handle/38848805888454780649.

Texte intégral

Résumé :

碩士
東南技術學院
防災科技研究所
96
This study focused on the properties of the cement asphalt mortar (CA). The mixtures of the samples are following as high performance concrete design method and are tested by compressive strength, bending strength, indirect tensile strength and wheel load tracking to probe into their engineering properties. In addition, comparison with the properties of hydraulic cement mortar samples as control is analyzed. The mix asphalt concrete using the way of cold mixture. The test results show that the compressive strength is hydraulic cement mortar > CA mortar; the bending strength at curing of 28 days is CA mortar > hydraulic cement mortar, however, at curing of 7 and 14 days is hydraulic cement mortar > CA mortar; and the indirect tensile strength is hydraulic cement mortar > CA mortar > Stone Mastic Asphalt (SMA) > hot mix asphalt > Porous Asphalt (PA). The performance analysis of the rutting resistance is following as cold mix asphalt with adding 6% cement > PA > SMA > CA mortar. The Scanning Electron Microscope (SEM) analysis results show that the Ca(OH2) increased with increases curing time. The CA mortar samples fabricated need an appropriate water for lubrication. Thus, the water absorption of fine aggregate must be concerned. The emulsion asphalt added too much may reduce the strength. Thus, the must confirm emulsion asphalt consumption. In the field test, the CA mortar performs very well, especially in workability. The weather condition,workers, machinery and construction areas are unlimited.

Styles APA, Harvard, Vancouver, ISO, etc.

45

Lang, Alexander Paul. « The prediction of coarse aggregate performance by micro-Deval and other soundness, strength, and intrinsic particle property tests ». Thesis, 2006. http://hdl.handle.net/2152/30367.

Texte intégral

Résumé :

This research project concentrated on determining whether or not a correlation existed between laboratory aggregate tests and observed aggregate field performance. For this purpose, aggregate samples were collected from the majority of the U.S. states as well as several Canadian provinces and subjected to a variety of strength, soundness, and intrinsic particle property tests. Additionally, performance data on the aggregates was obtained by contacting multiple DOT's where aggregates were in use in several categories - hot-mix asphalt, portland cement concrete, base course, and open-graded friction course. Numerical and qualitative analyses were performed to evaluate the success of separating good performers from fair and poor performers using the micro-Deval test alone as well as the micro-Deval test combined with another test. Furthermore, attempts were made to determine if a correlation exists between any two tests.

Styles APA, Harvard, Vancouver, ISO, etc.

46

Wu, Jia-Lin, et 吳佳霖. « Practicability Assessment of the Manholes with the Cement Asphalt Concrete ». Thesis, 2009. http://ndltd.ncl.edu.tw/handle/74660841840110001924.

Texte intégral

Résumé :

碩士
國立臺灣科技大學
營建工程系
97
In Taiwan, the conduit（cable）construction is one of the damage factories for pavement distress. These distresses such as cracking, depression, faulting and rutting have been caused by the road excavation due to the substandard backfill material or compaction procedure. Distresses and manholes are the mai.n responsible for poor roughness index and pavement service performance. Furthermore, the potholes are caused by the broken pavement surface in that the material properties of manhole site are differing from HMA. As s result this study is focued on how to improve the materials quality of manhole site The research evaluate and compare cement asphalt concrete (CAC) with manhole materials now available in Taiwan by doing both experiments in lab and examination on spot.According to the test results, the sensitivity of temperature of CAC is low and CAC tends to accelerates cement hydration in high temperature so that CAC benfits the development of mechanical strength.according to the research, CAC is found to be better than Dense-Graded Asphalt Concrete(DGAC) and Resin Asphalt concrete(RAC) on mechanical properties, durability, and pavement performance.Consequenthy CAC is proved to Practicability of manholes.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Shen, Ruei-Siang, et 沈瑞翔. « Evaluation of Cement－Emulsified Asphalt Mortar for Pavement Fast Repair ». Thesis, 2016. http://ndltd.ncl.edu.tw/handle/74943641834863981518.

Texte intégral

Résumé :

碩士
東南科技大學
營建與空間設計系營建科技與防災碩士班
104
Due to green environmental protection need, the materials used magnesium phosphate cement and emulsified asphalt in this study should be environmental friendly, and non-toxic and harmless. The characteristics of the magnesium phosphate cement has fast setting, high strength mixed with emulsified asphalt that mixtures can become the properties of firmness and flexibility. The mixtures as fast road repairing materials would be benefited the engineering properties of the Marshall stability value, shear strength, resistance to plastic flow and…etc. for specification required. The study designs to add three different ratios of fine aggregate for mixtures: (a) flexible pavement concepts sign as A-series; (b) rigid pavement concept sign as B-series; and (c) C-series used as fly ash. The properties of the fresh and hardened are tested as well. The results showed that only C-series type C-03 is satisfied by the specification of the flow of hydraulic cement mortar test and flow consistency test. The type of C-03 has the highest values in the Marshall stability values, indirect tensile strength and compressive strength after 28 days curing.

Styles APA, Harvard, Vancouver, ISO, etc.

48

郭孟菖. « Study on the Properties of Modified Waste Tire Powder with Asphalt Cement ». Thesis, 1997. http://ndltd.ncl.edu.tw/handle/44371736877124701747.

Texte intégral

Résumé :

碩士
中原大學
化學工程學系
85
Reclaimed rubber was obtained by using waste truck or bus tire rubber powder with the reaction of cuprous chloride-ethanolamine system. Rubber compound having a different ratio of reclaimed rubber to rubber powder was blended with asphalt cement to get a variety of modified rubber asphalt. In general, increasing mixed rubber, at a specified temperature, would increase the softening point, viscosity and penetration of modified rubber asphalt. But at a higher blending temperature, there was a decreasing of penetration for the reason of more oxidation. With the same consistency of mixed rubber blended, increasing the amount of reclaimed rubber or at a higher blending temperature, generally would increase softening point and viscosity, but would decrease penetration. Above 10% of mixed rubber blended and the more containing of reclaimed rubber, the more access to maintain the balance relation of anti-flow, anti-abrasion and anti-brittiness on pavement road.

Styles APA, Harvard, Vancouver, ISO, etc.

49

Yu, Meng-Chou, et 游孟洲. « The Influence of the cement and slag powder on asphalt concrete pavement ». Thesis, 2009. http://ndltd.ncl.edu.tw/handle/51899702755955433411.

Texte intégral

Résumé :

碩士
國立中興大學
土木工程學系所
97
It is generally known that there has been an increasingly greater demand for asphalt concrete every year for newly building and maintenance of bituminous pavements. The sources of asphalt concrete stopping are rock powder or cement. However, in considering the high cost of the cement and increased shortage of crushed stones, a raw material for the rock powder, due to environmental protection and conservation, the government has been reinforcing and promoting the regeneration policy. To comply with the government policy and solve the shortage problem, slag powder produced by steel factories is strongly recommended for regeneration purpose. This research aims to evaluate based on various testing the availability of cement or slag powder in different ratios for Marshall samples served as a filling for asphalt concrete. The testing performed includes stability, detention, idirect tensity and rutting tests. The experimental result shows that the six testing groups with different ratios of filling have all conformed to the standard value. However, the addition of more slag powder shows higher tensile strength, whereas it shows decreased rutting test with a decrease of slag powder. As to stability test, there is no significant difference between adding cement and slag powder. The above results demonstrate that the cement group may have slightly better overall effect. However, the difference is not significant between the two groups of filling. Therefore, in considering the economic cost, slag powder - resource of recycling material- may still serve as a good source of a filling for bituminous pavement.

Styles APA, Harvard, Vancouver, ISO, etc.

50

Lu, Cheng-Tsung, et 呂正宗. « The Cement-Asphalt Concrete Proportioning Design Technique and Its Utilization on Pavement ». Thesis, 2008. http://ndltd.ncl.edu.tw/handle/74572254885530621773.

Texte intégral

Résumé :

博士
國立臺灣科技大學
營建工程系
96
Nowadays, the application of cement to improve the property of emulsified asphalt, whether in theory or practice, has always involved the use of cement paste and emulsified asphalt mixture. However, this study decided to deviate from this convention because “additional water has to wet cement or aggregates before mixing emulsified asphalt.” Doing so prevents the emulsified asphalt and cement or the dry aggregates from directly mixing. In this regard, the current study can be considered a breakthrough and an innovative research because in the process employed, there is “no need to add prior water for wetting cement or aggregates so that concrete and emulsified asphalt can be mixed directly and evenly by superplasticizer." Such technology improves not only the uniformity when mixing cement and emulsified asphalt but also the mechanics strength of asphalt concrete. In this study, cement is used as modifier. Specifically, emulsified asphalt evenly mixes with FSP first and then directly mixes with cement to form cement-asphalt mastic (CAM). Afterwards, an adequate mixing ratio is ensured to combine CAM and the aggregate into cement-asphalt concrete (CAC) mixture. It is finally compacted as CAC. This research aims to analyze and estimate the proportion and mechanics property of both CAM and CAC. First, the composition and reaction mechanisms of CAM are investigated, followed by the proportion design of CAC. The study also elucidates the mechanics properties and paving performances of CAC as utilized on pavement. The following main results were generated. Research on the composition reaction mechanism of CAM has proven that the optimum dosage of a superplasticizer added to the CAM is FSP/A=2%-5%. This was confirmed in the study by conducting the Zeta potential test. Related potential changes also exhibited the causes behind the flocculation that resulted during the mixing process of emulsified asphalt and the superplasticizer. The principle behind the use of a superplasticizer as the media for the direct mixing of cement and emulsified asphalt was also determined. The results from this research indicated that cement-asphalt mastic is a mixture of cement-asphalt concrete whose viscosity is suitable for such application between 8000cPs and 12000cPs. In addition, the results of the Marshall Proportioning Design showed that the said design was unable to meet the proportional requirements of cement-asphalt concrete. Likewise, the minimum cement-asphalt mastic needed was used to support the proportional design required. After the related proportional design, trial conclusions stated that “the higher the content of cement in cement-asphalt concrete, the better the mechanical property, and the higher the content of superplasticizer, the nicer workability of the new mixture of cement and asphalt.” However, the amounts of cement and superplasticizer to be used have to be controlled because high-dose mixing may cause failure. The following quantity range of materials is suggested: 1.2≧C/A≧1; 0.05≧FSP/A≧0.03; CAM/CAC=0.25 and 12000cPs≧CAM Viscosity≧8000cPs. In terms of mechanical property, the research results showed that the modification of cement-asphalt concrete obtained better performance figures compared with those of hot-mixing asphalt concrete. These include increased pressure strength of 2.6-3.4 times that of 28 days, increased shear strength of 5.4-6.5 times that of 28 days, increased tension strength of 6-8 times that of 28 days, and enhanced Marshall Stability value of up to 6.2-7.9 times. Furthermore, its durability and resistance against rutting were enhanced. Therefore, concrete mixed with cement-emulsified asphalt concrete is characterized by excellent and significant mechanical property modification, as well as flow value that retains asphalt concrete pavement softness. The estimated results of paving performance are presented in this study, including cement enhances CAC immersing resistance and residual strength index. The residual strength index of CAC reached 80%-90% and the CAC rut showed evident decline. At a 24-hour period of CAC, its rut is near to none. Therefore, the paving performance of CAC offers several advantages. Among them are excellent pavement service, prolonged pavement use, reduced paving maintenance cost, and pavement damage prevention, which could avoid potential danger to road users.

Styles APA, Harvard, Vancouver, ISO, etc.

Thèses sur le sujet « Asphalt cement »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres