Academic literature on the topic 'Mixture durability'
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Journal articles on the topic "Mixture durability":
1
Xia, Chaoming, Chaofan Wu, Kefei Liu, and Kang Jiang. "Study on the Durability of Bamboo Fiber Asphalt Mixture." Materials 14, no. 7 (March 28, 2021): 1667. http://dx.doi.org/10.3390/ma14071667.
Abstract:
To evaluate the durability of bamboo fiber asphalt mixture using four gradation schemes, the durability of the bamboo fiber asphalt mixture is studied considering three aspects: ageing durability, freeze-thaw cycle durability and fatigue durability through the Marshall test, indoor ageing test, uniaxial compression test, low-temperature bending test, immersion Marshall test, freeze-thaw splitting test and four-point bending fatigue test. Nonfiber asphalt mixture and lignin fiber asphalt mixture were used as control groups. The results show that the addition of plant fiber can effectively improve the durability of asphalt mixture. Bamboo fiber modified asphalt mastic has good ductility and adhesion due to its rough surface and good oil absorption performance. Bamboo fiber asphalt mixture has better and more stable low-temperature ageing durability and moisture ageing durability than lignin fiber asphalt mixture, but its mechanical property is weaker than the latter. The improvement effect of the two fibers on the freeze-thaw cycle durability of asphalt mixture is basically the same. Bamboo fiber can improve the flexibility of the mixture and delay the development of cracks so that the mixture has good fatigue durability. The smaller the void ratio, the thicker the asphalt film, and the denser the structure of the mixture, the better the durability. The durability of the stone mastic asphalt (SMA) gradation mixture is better than that of asphalt concrete (AC) gradation. The material composition and aggregate gradation of plant fiber asphalt mixture have a great influence on its durability. In the future, it is necessary to establish a multiparameter comprehensive evaluation index system among fiber type and properties, mixture gradation and durability so as to realize the directional regulation of the durability of different fiber asphalt mixtures. Bamboo fiber is a reliable substitute for lignin fiber, and further research on improving its surface properties and dispersion uniformity can be carried out in the future.
2
Mardani-Aghabaglou, Ali, Süleyman Özen, and Muhammet Gökhan Altun. "DURABILITY PERFORMANCE AND DIMENSIONAL STABILITY OF POLYPROPYLENE FIBER REINFORCED CONCRETE." Journal of Green Building 13, no. 2 (March 2018): 20–41. http://dx.doi.org/10.3992/1943-4618.13.2.20.
Abstract:
In this study, the durability performance and dimensional stability of polypropylene fiber reinforced concrete mixture were investigated. For this purpose, two series of concrete mixtures, including a 0.45 water/cement ratio was prepared both in the absence and presence of fiber. A CEMI 42.5 R type portland cement and crushed limestone aggregate with a maximum particle size of 25 mm were used. In addition to the control mixture without fiber, three different concrete mixtures were prepared by adding polypropylene fiber as 0.4%, 0.8% and 1% of total volume into the mixture. The time-dependent fresh state properties, strength, ultrasonic pulse velocity, transport properties, drying shrinkage and freeze-thaw resistance of concrete mixtures, sodium sulfate attack and abrasion were investigated comparatively. Test results demonstrated that utilization of fiber affected the fresh properties of the concrete mixtures negatively. However, the 0.8% fiber-bearing mixture showed the highest performance in terms of durability and dimensional stability. Beyond this utilization ratio, the durability performance of the concrete mixture was negatively affected. The risk of nonhomogeneous dispersion of the fiber in the mixture was relatively high in the excess fiber-bearing mixture. Consequently, with the formation of flocculation in the mixture the void ratio of concrete mixture increased.
3
Šefflová, Magdaléna, and Tereza Pavlů. "The Durability of Fine Recycled Aggregate Concrete." Advanced Materials Research 1144 (March 2017): 59–64. http://dx.doi.org/10.4028/www.scientific.net/amr.1144.59.
Abstract:
This paper is focused on the durability of recycled aggregate (FRA) concrete. The durability of FRA concrete is connected with many uncertainties and doubts. This paper presents results of long-term of compressive strength, freeze – thaw resistance and carbonation depth of FRA concrete. The FRA was originated from crushed old concrete structures. There were prepared a total four concrete mixture. The first mixture was reference with natural sand. In other concrete mixtures, natural sand was replaced by the FRA in various replacement ratios, specifically 10 %, 20 % and 30 %. All prepared concrete mixtures were designated with the same parameters for clear comparison. It is possible to say that according to the durability, the FRA concrete is possible to used in the same applications as conventional concrete. However it is necessary to verify this results.
4
Mardani-Aghabaglou, Ali, Ahsanollah Beglarigale, Halit Yazıcı, and Kambiz Ramyar. "COMPARISON OF RECYCLED GLASS AND RECYCLED CONCRETE AGGREGATES BEARING MORTAR MIXTURES EXPOSED TO HIGH TEMPERATURE, ABRASION AND DRYING." Journal of Green Building 13, no. 4 (September 2018): 39–59. http://dx.doi.org/10.3992/1943-4618.13.4.39.
Abstract:
In this study, the effects of recycled glass (RG) and recycled concrete (RC) fine aggregates on the drying-shrinkage, carbonation, high temperature and abrasion resistance of mortar mixtures were investigated comparatively. In addition, durability performance of the mortar mixtures was investigated through micro-structural analysis. For this purpose, 9 different mortar mixtures were prepared by replacing 25, 50, 75 and 100 wt.% of crushed-limestone fine aggregate with recycled glass and recycled concrete aggregates. Except for the abrasion resistance, the RG mixtures showed better durability performance than the control mixture. However, the RC mixtures containing more than 50% recycled aggregate showed lower performance than the control mixture.
5
Nahyo, Nahyo, Sudarno Sudarno, and Bagus Hario Setiadji. "DURABILITAS CAMPURAN HOT ROLLED SHEET-WEARING COURSE (HRS-WC) AKIBAT RENDAMAN MENERUS DAN BERKALA AIR ROB." Jurnal Teknik Sipil Unaya 1, no. 2 (March 1, 2019): 141–54. http://dx.doi.org/10.30601/jtsu.v1i2.14.
Abstract:
Tide phenomenon that often occurs in the coastal areas of Indonesia resulted in flooding, which is called the tidal flood. A tidal flood overflow phenomenon of sea water inland. Often some of the roads located in coastal areas are flooded by tidal flood and often causing some damages to the road. Therefore it is necessary to investigate the effect caused by tidal inundation or water bath for asphalt pavement.This research aims to know the durability performance of asphalt concrete mixtures with marinade modification Marshall. The study was conducted with two standard methods of soaking in tidal water and laboratory. Water Immersion method is made by soaking continuous (continuous) and periodic (intermittent). Soaking the specimen in water tidal variation within 6 hours; 12 hours; 24 hours; 48 hours; and 72 hours. While the periodic immersion done by soaking the specimen for 12 hours, then removed during the next 12 hours during 3-days. To view the durability performance of asphalt concrete mixtures used indicator Index of Retained Stability (IRS), Stability Deformation Index, namely First Durability Index (IDP), and the Second Durability Index (IDK).The results showed that continuous immersion damage effects mix quicker on asphalt mixtures than regular immersion. Tidal water used to soak the asphalt mixture Hot Rolled Sheet-Wearing Course (HRS-WC) either continuous or periodic method, has a greater influence than the use of laboratory water. It is shown by the value of the durability of asphalt mixture soaked-tidal water smaller than water-soaked asphalt mixture laboratory standards.
6
Wang, Xuancang, Zhenyang Fan, Li Li, Hongyao Wang, and Minghui Huang. "Durability Evaluation Study for Crumb Rubber–Asphalt Pavement." Applied Sciences 9, no. 16 (August 20, 2019): 3434. http://dx.doi.org/10.3390/app9163434.
Abstract:
In this study, the failure mechanism of crumb rubber–asphalt pavement was analyzed under the combined effects of low temperature, water, and traffic load. The investigation was carried out based on the mechanical and deformational properties of crumb rubber–asphalt mixture and the typical environmental and load conditions such pavement is typically exposed to. A method was proposed for objective evaluation of the interfacial adhesion between rubber crumbs and asphalt through consideration of the effects of the characteristics of the materials and the working environment. The main evaluation method used herein included the indirect tensile strength test under freeze–thaw–boiling cycle, and the Cántabro abrasion test under water-immersion was adopted as an auxiliary method. The evaluation system has the advantages of simple implementation, realistic simulation of the actual working state of the mixture, and reliable results. Moreover, it is a durability evaluation method that can be specifically applied to asphalt mixtures with some special aggregates or stone mastic asphalt (SMA) mixtures.
7
Li, Qingfu, and Jing Hu. "Mechanical and Durability Properties of Cement-Stabilized Recycled Concrete Aggregate." Sustainability 12, no. 18 (September 9, 2020): 7380. http://dx.doi.org/10.3390/su12187380.
Abstract:
This research investigates the effect of using recycled concrete aggregate (RCA) as a partial replacement of natural aggregate (NA) on the mechanical and durability-related properties of a cement-stabilized recycled concrete aggregate (CSR) mixture. In this case, mixtures were prepared with 0%, 40%, 70%, and 100% (by weight) RCA to replace NA, and cement contents of 4%, 5%, and 6% were used in this study. Test parameters included the replacement ratio, cement content, and curing time. Tests were carried out to establish the unconfined compressive strength (UCS), indirect tensile strength (ITS), drying shrinkage, and water loss ratio of each mix proportion. The preliminary results of UCS and ITS tests indicated that the incorporation of RCA resulted in a decrease of strength compared with a cement-stabilized macadam (CSM) mixture, but the seven-day strength of the CSR mixture met the related requirements of road bases. The increase in cement content and curing time had an obvious effect on strength improvement. The drying shrinkage test showed that the drying shrinkage properties of the CSR mixture were obviously reduced with a high replacement ratio. It is evident that the CSM mixture presented a better drying shrinkage performance than that of the CSR mixture.
8
Wang, Xiao-Yong. "Impact of Climate Change on the Optimization of Mixture Design of Low-CO2 Concrete Containing Fly Ash and Slag." Sustainability 11, no. 12 (June 19, 2019): 3394. http://dx.doi.org/10.3390/su11123394.
Abstract:
Fly ash and slag have been widely used to produce low-CO2 concrete. However, previous studies have not paid enough attention to the lower carbonation resistance of fly-ash-and-slag-blended concrete and the aggravations of carbonation due to climate change. This study proposes a technique for the design of fly-ash-and-slag-blended concrete considering carbonation durability coupled with various climate change scenarios. First, CO2 emissions are evaluated from concrete mixtures. Concrete strength and carbonation depth are evaluated using efficiency factors of fly ash and slag. A genetic algorithm (GA) is used to find the optimal mixture with the lowest CO2 emissions considering the requirements of strength, carbonation durability, and workability. Second, we clarify the effect of cost on the mixture design of low-CO2 concrete. A genetic algorithm is also used to find the optimal mixture with the lowest cost. We found that the optimal mixture with the lowest cost is different from that with the lowest CO2 emissions. Third, by adding the additional constraint of cost, Pareto optimal mixtures are determined, which consider both lower CO2 emissions and lower material cost. The analysis results show that carbonation durability is the control factor of mixture design of fly ash-slag blended concrete. To mitigate the challenge of climate change, the binder content of blended concrete should be increased.
9
Akbari Motlagh, Ali, and Ebrahim Mirzaei. "Effect of using Fibre on the Durability of Asphalt Pavement." Civil Engineering Journal 2, no. 2 (February 1, 2016): 63–72. http://dx.doi.org/10.28991/cej-2016-00000013.
Abstract:
Using the fibre additives with a uniform distribution in asphaltic concrete mixture is a well-known technique for improving the mechanical properties and durability of asphalt pavement. The purpose of this study is to investigate the effect of preparing fibre and production of the properties of bitumen and asphalt concrete mixture. In this study, a dense-graded aggregation, mineral fibres (asbestos) and synthetic fibres (polyester and nylon) were used. Laboratory studies were done by comparing different rheological properties, mechanical and moisture susceptibility of mixtures of fibres. Results of the penetration and softening point on mixtures of bitumen – fibre show that fibres improve the mixed rheological properties and stiffening effect of fibre properties. The results of Marshall Tests indicate that adding fibres reduces the strength in Marshall and results in the slight increase in the percentage of optimum bitumen content and asphalt percentage of air voids in comparison with typical fibre. The results of the indirect tensile tests showed that the addition of fibres, depending on the percentage of fibres significantly improves the durability of the mixture.
10
Šefflová, Magdaléna, and Tereza Pavlů. "Non-Destructive Testing of Concrete with Fine Recycled Aggregate." Applied Mechanics and Materials 825 (February 2016): 63–68. http://dx.doi.org/10.4028/www.scientific.net/amm.825.63.
Abstract:
This paper is focused on non-destructive testing of concrete containing fine recycled aggregate (FRA). FRA was obtained from demolished concrete structures and crushed in the laboratory on fraction 0 – 4 mm. There were prepared four concrete mixtures. The first concrete mixture was control, did not include FRA. In other mixtures was natural replaced natural sand by FRA. There were tested workability of fresh concrete mixture and physical properties of hardened concrete. Finally, it is possible to say that the use of FRA influences the physical properties of concrete. The physical properties of concrete are connected with the durability of concrete. Therefore, it is necessary to focus on durability testing of FRA concrete in further research.
Dissertations / Theses on the topic "Mixture durability":
1
Kraus, Zachary Rothman. "The morphology of polymer modified asphalt and its relationship to rheology and durability." Texas A&M University, 2008. http://hdl.handle.net/1969.1/86003.
Abstract:
Polymers are added to asphalt binders primarily to stiffen the binder at higher
temperatures and thus to protect the pavement against rutting at summertime
temperatures early in the pavement's life. Also, it has been noted that polymers typically
increase the ductility of a binder and that some polymer-asphalt combinations are
especially effective. Furthermore, it is hypothesized that enhancing a binder's ductility,
and maintaining this enhancement with binder oxidative aging, contributes to enhanced
binder durability in pavements. However, polymer-asphalt interactions and how they
might contribute to improved binder performance is not well understood. The goal of
this work was to probe the relationship of polymer morphology on asphalt binder
rheology and mixture durability.
Experiments were conducted on asphalt mixtures and binders, and as a function
of oxidative aging. PFC mixtures, which are an open mixture designed to allow
enhanced water drainage, were of specific interest. These mixtures were tested for
Cantabro Loss, an indicator of a mixture's likelihood of failure by raveling. Asphalt
binders were tested using dynamic shear rheometry (DSR), which provided the DSR
function, (G' /η'/G'), a measure of binder stiffness that includes both the elastic modulus
and the flow viscosity), ductility (used to measure the elongation a binder could
withstand before failure), gel permeation chromatography (GPC), used to estimate the
relative amount of polymer) and fluorescence microscopy (used to image the polymer
morphology in the asphalt binder). From these data, relationships were assessed between binder morphology and
binder rheology and between binder rheology and mixture durability, all as a function of
binder oxidative aging. Polymer morphology related to ductility enhancement. Polymer
morphology related to a change in the DSR function, relative to the amount of polymer,
as measured by the polymer GPC peak height. Cantabro loss correlated to the DSR
function (R2=0.963). The overall conclusion is that polymer morphology, as indicated by
fluorescence microscopy, relates to both the rheological properties of the binder and the
Cantabro loss of the mixture. These relationships should yield a better understanding of
polymer modification, increased mixture durability (decreased raveling) and improved
rheological properties (DSR function and ductility).
2
Beck, Lisa Elanna. "Diffusivity and resistance to deterioration from freezing and thawing of binary and ternary concrete mixture blends." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/8784.
Abstract:
Master of ScienceDepartment of Civil Engineering
Kyle Riding
Corrosion of reinforcing steel is one of the most common and serious causes of reinforced concrete deterioration. While corrosion is normally inhibited by a passive layer that develops around the reinforcing steel due to the high pH environment of the surrounding concrete, chlorides will break down this protective layer, leading to reinforcement corrosion. Decreasing the diffusivity of the concrete would slow the ingress of chlorides into concrete, and is one of the most economical ways to increase the concrete service life. Optimized concrete mixtures blending portland cement and supplementary cementing materials (SCMs) have become popular throughout the construction industry as a method of improving both fresh and long-term concrete properties such as workability, strength and porosity. It has been shown that use of Class F fly ash, silica fume and ground granulated blast furnace slag (GGBFS) in binary concrete mixture blends can result in a significant reduction in concrete diffusivity. This study investigates the ability of Class C fly ash and ternary concrete mixture blends to also aid in diffusivity reduction. In order to study the effect of incorporation of SCMs into concrete, mixtures containing Class C and Class F fly ash, silica fume and GGBFS were tested following the ASTM C 1556 procedures to measure the concrete’s apparent chloride diffusivity. Structure life cycles were modeled using the measured apparent chloride diffusivities with two finite-difference based life-cycle analysis software packages. To determine whether a correlation between diffusivity and deterioration due to freezing and thawing exists, samples were also tested for their ability to resist deterioration from freezing and thawing cycles using a modified ASTM C 666 Procedure B test. Results show that the use of Class C fly ash yields some service life improvements as compared to the portland cement control mixtures, while ternary mixture blends performed significantly better than the control mixture and equal to or better than the binary SCM mixtures tested. Freeze-thaw tests showed all mixtures to be equally resistant to deterioration due to freezing and thawing.
3
Scholz, Todd V. "Durability of bituminous paving mixtures." Thesis, University of Nottingham, 1995. http://eprints.nottingham.ac.uk/11469/.
Abstract:
Bitumens are used as a binder in roadway pavements largely because they are relatively inexpensive and generally provide good adhesion and waterproofing characteristics. They are generally rather resistant to the detrimental effects of the environment and usually remain pliant for many years. In other words, bitumens are relatively inexpensive binders that generally provide good durability (or longevity of service) in pavement mixtures. Bitumens are no panacea, however. Many factors affect the durability of bitumens and, thus, bituminous mixtures. However, assuming that a pavement layer is constructed according to specifications (which attempt to account for durability), it is generally agreed that the two primary factors affecting the durability of bituminous paving mixtures are damage due to water and embrittlement of the bitumen due to age hardening. Much effort has been afforded to the study of age hardening and water damage and much has been learned. However, the exact mechanisms of ageing and water damage in bituminous mixtures remains an enigma. This thesis attempts to provide an improved understanding of these mechanisms through a comprehensive literature review, development of performance tests to assess mixture durability and investigation of the rheological characteristics of bitumens aged and tested whilst in contact with mineral aggregate.
4
Noferini, Luca <1984>. "Performances and Durability of Asphalt Mixtures Made with Reclaimed Asphalt Pavement." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7463/.
Abstract:
According to most recent surveys, 265 mil tonnes of asphalt for road applications were produced in the European area in 2014. In the same year, the amount of available RAP was more than 50 mil tonnes. The use of RAP in new blended mixes reduces the need of neat bitumen, making RAP recycling economically attractive. In spite of its economic and environmental benefits, the use of RAP is often subjected to restrictive policies pursued by agencies due to uncertainty related to RAP mixes field performances.
This thesis focuses on the effects of RAP on performances and durability of new asphalt mixes produced incorporating RAP with a standard hot-in-plant process. The influence of RAP being incorporated in new mixes was investigated through an extensive laboratory testing campaign on asphalt mixtures and on bitumen recovered from the same mixes.
A specific typology of asphalt mixture has been produced with different RAP percentages of 10%, 20% and 30%. In the first phase of the research, asphalt materials have been characterized and compared in terms of resistance to fatigue, stiffness and volumetric properties. The second phase of the research aims to investigate the effects of RAP on asphalt binder as a composite blend of neat and RAP bitumen. Bituminous samples have been recovered from asphalt samples tested in phase 1 and then have been studied and compared with standard and dynamic laboratory tests.
Findings show that HMA can be successfully produced incorporating up to 20% of RAP in the fresh mix. For these percentages of RAP being recycled, no negative effects on performances and durability of recycled mixtures have been noted. However, the final bitumen grade of the mix may be adjusted if more than 20% of RAP is added. Furthermore, practical implications regarding production methods and paving of RAP mixes are proposed.
5
Loulou, Louisa. "Durabilité d’un assemblage mixte bois-béton collé sous chargement hydrique." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1123/document.
Abstract:
La mixité bois-béton est une solution intéressante dans le domaine des ouvrages d'art pour la réalisation de ponts, et dans le domaine du bâtiment dans la confection de planchers mixtes bois-béton. Le laboratoire Navier travaille depuis plusieurs années au développement du procédé par collage appliqué aux structures mixtes bois-béton. En effet, cette technique d'assemblage permet d'assurer une connexion quasi-parfaite entre le bois et le béton, contrairement aux techniques d'assemblage usuelles (connecteurs métalliques). Des travaux antérieurs ont montré la bonne performance de structures mixtes collées bois-béton du point de vue de leur tenue mécanique en fatigue. Cependant la connexion par collage nécessite une étude complémentaire concernant la durabilité de l'assemblage collé bois-béton, en particulier lorsque la structure mixte est soumise à des conditions hygrométriques variables. Les travaux menés pendant la thèse ont pour objectifs de déterminer les facteurs qui influent sur la tenue de ces assemblages collés sous chargement hydrique ; ils se divisent en 3 parties :-Deux parties expérimentales :(1)Des tests de cisaillement « Push-Out », en collaboration avec le Laboratoire Départemental d'Autun, ont permis d'évaluer l'effet des propriétés élastiques de l'adhésif sur la tenue en cisaillement de l'assemblage. L'objet de cette étude expérimentale est de valider un choix de colle pour ce type d'assemblage, prenant en compte un vieillissement hydrique, en se basant sur la capacité maximale atteinte en cisaillement, et le mode de rupture de l'assemblage. (2)Parallèlement aux tests de cisaillement, l'effet de chargements hydriques sur la tenue d'assemblages collés bois-béton a été étudié. L'analyse du comportement hydrique de la structure a été réalisée par la technique de corrélation d'image (DIC) sur des assemblages bois-béton collé de petite taille. Ces mesures de déformations locales ont permis de localiser des zones d'endommagement liées notamment aux déformations hydriques du bois empêchées par l'interface collée. Les effets des propriétés élastiques de l'adhésif, de la géométrie du bois (notamment sa structure et le sens des cernes par rapport au plan de collage) ainsi que du comportement mécanique du matériau cimentaire ont été étudiés.- Une partie numérique :(3) Un modèle numérique par éléments finis a été validé en comparant les résultats numériques aux cartes de déformation obtenues expérimentalement. L'analyse numérique a permis de quantifier les contraintes induites au niveau de l'interface en relation avec les déformations hydriques empêchées par l'interface collée et de prévoir le comportement à l'échelle 1 de structures mixtes. Ces différentes investigations ont permis de proposer des solutions optimisant ce type de connexion et de définir des conditions de mise en œuvre et d'utilisation de ces assemblagesThe wood-concrete composite is an interesting solution in the field of Civil Engineering to create high performance bending elements for bridge, as well as in the building construction for the design of wood-concrete floor systems. The Navier laboratory has been working for many years on the development of the bonding process as applied to wood-concrete composite structures. Contrary to conventional joining connectors (metal connectors), this assembling technique does ensure an almost perfect connection between wood and concrete. Previous work has already shown good performances of glued wood-concrete composite structures in terms of mechanical fatigue. However, the bonding connection requires additional research on the long-term behaviour of glued wood-concrete composites, especially when this structure is subjected to variable hygrometric conditions. The work undertaken during this thesis aims at determining the factors which induce damages on these glued wood-concrete assemblies under hygrometric loading; the research is divided into 3 parts:-Two experimental parts:(1)"Push-Out" shear tests conducted in collaboration with the Departmental Laboratory of Autun, were used to assess the effect of the elastic properties of the resin on the shear strength of the assembly. This experimental study aims at validating the adhesive of choice for this kind of connection, taking into account ageing under variable hygrometric conditions. Analysis is based on maximum shear capacity and on the failure mode of the assembly. (2)In addition to shear tests, the effect of hygrometric loading on the durability of glued wood concrete assemblies was examined. The analysis of the hydric behaviour of the structure was carried out by the digital image correlation (DIC) technique on small-sized glued wood-concrete assemblies. The measurements of the local deformations allowed us to locate areas of damage, particularly due to the hydric deformations of the wood prevented by the glued connection The effects of the elastic properties of the resin, the microstructure of the wood (including its structure and the direction of the annual rings) as well as the mechanical behaviour of the concrete material were examined.- A numerical part:(3) A numerical finite element model was validated by comparing the numerical results to the deformation maps experimentally obtained. Numerical analysis was used to quantify the stresses induced to the structure, in relation to hydric deformations prevented by glued connection. Moreover investigations at the full scale were conducted to evaluate the long-term behaviour under variable hygrometric conditions. These investigations were conducted in order to offer solutions aiming at optimizing this type of connection, and to define conditions for use of these glued assemblies
6
Loulou, Louisa. "Durabilité d'un assemblage mixte bois-béton collé sous chargement hydrique." Phd thesis, Université Paris-Est, 2013. http://pastel.archives-ouvertes.fr/pastel-00952884.
Abstract:
La mixité bois-béton est une solution intéressante dans le domaine des ouvrages d'art pour la réalisation de ponts, et dans le domaine du bâtiment dans la confection de planchers mixtes bois-béton. Le laboratoire Navier travaille depuis plusieurs années au développement du procédé par collage appliqué aux structures mixtes bois-béton. En effet, cette technique d'assemblage permet d'assurer une connexion quasi-parfaite entre le bois et le béton, contrairement aux techniques d'assemblage usuelles (connecteurs métalliques). Des travaux antérieurs ont montré la bonne performance de structures mixtes collées bois-béton du point de vue de leur tenue mécanique en fatigue. Cependant la connexion par collage nécessite une étude complémentaire concernant la durabilité de l'assemblage collé bois-béton, en particulier lorsque la structure mixte est soumise à des conditions hygrométriques variables. Les travaux menés pendant la thèse ont pour objectifs de déterminer les facteurs qui influent sur la tenue de ces assemblages collés sous chargement hydrique ; ils se divisent en 3 parties :-Deux parties expérimentales :(1)Des tests de cisaillement " Push-Out ", en collaboration avec le Laboratoire Départemental d'Autun, ont permis d'évaluer l'effet des propriétés élastiques de l'adhésif sur la tenue en cisaillement de l'assemblage. L'objet de cette étude expérimentale est de valider un choix de colle pour ce type d'assemblage, prenant en compte un vieillissement hydrique, en se basant sur la capacité maximale atteinte en cisaillement, et le mode de rupture de l'assemblage. (2)Parallèlement aux tests de cisaillement, l'effet de chargements hydriques sur la tenue d'assemblages collés bois-béton a été étudié. L'analyse du comportement hydrique de la structure a été réalisée par la technique de corrélation d'image (DIC) sur des assemblages bois-béton collé de petite taille. Ces mesures de déformations locales ont permis de localiser des zones d'endommagement liées notamment aux déformations hydriques du bois empêchées par l'interface collée. Les effets des propriétés élastiques de l'adhésif, de la géométrie du bois (notamment sa structure et le sens des cernes par rapport au plan de collage) ainsi que du comportement mécanique du matériau cimentaire ont été étudiés.- Une partie numérique :(3) Un modèle numérique par éléments finis a été validé en comparant les résultats numériques aux cartes de déformation obtenues expérimentalement. L'analyse numérique a permis de quantifier les contraintes induites au niveau de l'interface en relation avec les déformations hydriques empêchées par l'interface collée et de prévoir le comportement à l'échelle 1 de structures mixtes. Ces différentes investigations ont permis de proposer des solutions optimisant ce type de connexion et de définir des conditions de mise en œuvre et d'utilisation de ces assemblages
7
Adhikari, Bikash. "Mechanical and Durability Characteristics of Fly Ash Based Soil-Geopolymer Mixtures for Road Base and Subbase Layers." Thesis, University of Louisiana at Lafayette, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10287480.
Abstract:
In this research study, high plastic and medium plastic soils were used in evaluating the physical and mechanical properties of fly ash-soil Geopolymer mixtures. Sieve analysis and Atterberg limit tests were conducted to classify the soil. Class F fly ash, an industrial byproduct, was used in the alkaline environment of a mixture of sodium silicate and various concentration of sodium hydroxide to prepare fly ash based Soil-Geopolymer mixtures. The modified proctor test was conducted to investigate the moisture-density characteristics of mixtures. Based on literature search and preliminary experiments, the experimental design matrix of was developed by using various combination of fly ash content, alkaline ratio, and concentration of sodium hydroxide. Several mixtures based on the experimental design matrix were compacted, cured at elevated temperature and tested for unconfined compressive strength. Regression analysis was conducted to develop regression models to optimize and conduct sensitivity of the compressive strength in relation to mix variables of Soil-Geopolymer mixtures. Based on sensitivity analysis and UCS criteria recommended by DOTD Louisiana, two mixtures were selected for further evaluation along with Standard soil-cement mixtures. The resilience modulus, dynamic modulus, and durability test were conducted for selected Soil-Geopolymer mixtures and standard soil-cement mixtures, as recommended by LA DOTD. The result of the study showed that the alkali activated soil-fly ash mixtures fulfilled the compressive strength criteria of cement treated design (CTD) and cement stabilize design (CSD) of 150 psi and 300 psi, as recommended by LA DOTD. Also, the results indicated that Soil-Geopolymer showed satisfactory performance under compressive strength test and dynamic loading tests. Further, the Soil-Geopolymer mixtures passed wet and dry durability test criteria. Based on mechanical and durability characteristics evaluated it can be recommended that Soil-Geopolymer mixtures studied in this study has an immense potential to be used as pavement subgrade, subbase, and bases.
8
Ahmed, Ananna. "Evaluation of cracking potential of superpave mixtures with high reclaimed asphalt pavement content." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20411.
Abstract:
Master of ScienceCivil Engineering
Mustaque A. Hossain
Approximately 89% of 11,000 miles of Kansas roads are surfaced with asphalt. Hundreds of thousands of tons of reclaimed asphalt pavement (RAP) are produced annually in the United States, including in Kansas. This bulk volume of RAP must be economically managed in order to achieve environmental friendliness. Recycling of RAP conserves natural resources and reduces landfill usage. However, many agencies have reported that increased RAP content produces drier hot-mix asphalt (HMA) mixtures than virgin mixtures that are susceptible to premature cracking. In this research, laboratory-produced Superpave HMA mixtures containing increased percentages (20, 30, and 40%) of RAP materials from three RAP sources (Shilling Construction Co., Konza Co., and the Kansas Department of Transportation’s project, US 73) were studied for cracking performance. Mix designs were produced using Superpave design criteria for 12.5-mm nominal maximum aggregate size mixture. The static and repetitive Semicircular Bending (SCB) test, the Texas Overlay Tester test, the dynamic modulus test, and Viscoelastic Continuum Damage (VECD) tests were performed on laboratory-prepared samples. In general, cracking performance decreased with increased RAP content. The RAP from the US 73 project performed most consistently compared to other two sources of RAPs. Test results were analyzed using two-way Analysis of Variance (ANOVA), proving that mixtures containing 4.5% to 4.9% binder performed the best against cracking. The RAP source was found to have more effect on cracking propensity than RAP content. Mixtures with RAP content up to 40% performed satisfactorily. Tukey’s pairwise comparison method was used to compare results from all tests; VECD was determined to be the most appropriate test to evaluate cracking propensity of HMA mixtures.
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Zidol, Ablam. "Durabilité en milieux agressifs des bétons incorporant la poudre de verre." Thèse, Université de Sherbrooke, 2014. http://hdl.handle.net/11143/5954.
Abstract:
Résumé : Des études récentes menées à l'Université de Sherbrooke ont montré que la poudre de verre possède des propriétés pouzzolaniques très intéressantes et peut être utilisée comme ajout cimentaire alternatif. Les premiers résultats de ces études ont révélé que la poudre de verre performe mieux dans des bétons de rapports E/L élevés comparativement à ceux de rapports E/L faibles. En effet, lorsqu’un même taux de poudre de verre est incorporé dans des bétons de rapports E/L différents, notamment E/L = 0,55 et E/L = 0,40 avec des dosages en liant respectifs de 350 kg/m3 et de 400 kg/m3; une pénétrabilité des ions chlorure similaire dans les deux cas est observée suggérant une bonne durabilité de ce type de béton même à des rapports E/L élevés.
Les objectifs visés dans ce projet qui porte sur l’étude de la durabilité en milieux agressifs des bétons incorporant la poudre de verre sont (1) la consolidation de la tendance révélée par la poudre de verre dans les deux types de bétons en élargissant le rapport E/L tout en incluant d’autres ajouts minéraux classiques pour fin de comparaison de leurs effets; (2) la mise en évidence de l'efficacité de la faible pénétrabilité des ions chlorure des bétons malgré leurs rapports E/L élevés, vis-à-vis de la résistance à certains phénomènes de dégradation ou agents extérieurs potentiellement agressifs tels que les sulfates, les chlorures, la carbonatation ou la corrosion. Cette étude s’intéresse également à la caractérisation mécanique et microstructurale permettant de comprendre et d'élucider les mécanismes d'action de la poudre de verre afin de cerner davantage son comportement dans les matrices cimentaires.
Pour cela, plusieurs rapports E/L variant de 0,35 à 0,65 (0,35 ≤ E/L ≤ 0,65) ont d’abord été considérés pour formuler une première série de bétons ayant différents dosages en eau. Les résultats de la résistance en compression, de la pénétrabilité des ions chlorure et de la perméabilité à l’eau obtenus de ces investigations sont en parfait accord avec la tendance initialement observée pour les deux rapports E/L = 0,55 et 0,40.
Par la suite, trois (3) rapports E/L de 0,55, 0,45 et 0,40 ont été sélectionnés pour reproduire une seconde série de bétons pour les études des propriétés de transports des bétons et des essais de vieillissement accélérés tels que la carbonatation et la corrosion. Tandis que la résistance aux sulfates a été évaluée sur des échantillons de mortiers. Les principaux résultats montrent une légère augmentation de la porosité totale et de la perméabilité au gaz des bétons en présence de la poudre de verre ou de la cendre volante de classe F. Cependant, la perméabilité à l’eau et les autres propriétés de transport impliquant les ions chlorure se trouvent considérablement réduites en présence de la poudre de verre ou des autres ajouts classiques. L'efficacité de la faible pénétrabilité des bétons en présence de la poudre de verre quel que soit le rapport E/L, est bien mise en évidence vis-à-vis de l'initiation à la corrosion induite par les chlorures mais l’est relativement peu sur l'évolution du front de carbonatation initiale accélérée. Par ailleurs, tout comme la cendre volante et contrairement au laitier, les bétons incorporant la poudre de verre développent lentement des résistances à la compression à jeune âge. Toutefois, une combinaison de la poudre de verre avec du métakaolin présente de très bonnes synergies et permet de pallier le déficit de résistance à jeune âge de ce type de béton.
Il ressort de cette étude que les effets de la poudre de verre sur les propriétés du béton, s’apparentent essentiellement à ceux de la cendre volante de classe F. Globalement les résultats de cette étude mettent en exergue la contribution substantielle de la poudre de verre à l’amélioration de la résistance des bétons aux attaques extérieures étudiées et supportent son emploi dans les matériaux de construction. // Abstract : Recent research conducted at the Université de Sherbrooke showed that glass powder has very interesting pozzolanic properties and can thus be used as an alternative cementitious material. These investigations showed that glass powder performs better in concretes with high water-to-binder ratio (w/b) than those with low w/b ratio. Similar penetration of chloride ions was measured for concrete incorporating the same rate of glass powder but designed with w/b ratios of 0.55 and 0.40 (with binder dosages of 350 kg/m³ and 400 kg/m³, respectively), indicating good durability of this type of concrete even at higher w/b ratio. The present study investigates the durability of concrete incorporating glass powder in aggressive environments. It aims (1) to consolidate the trend previously described by extending the range of investigated w/b ratios and (2) to highlight effectiveness of the low chloride ions penetrability despite a high w/b of concretes on their resistance against aggressive external agents such as sulphates, chlorides,
carbonation or corrosion. This study also examines the mechanical and microstructural properties of concretes to understand and elucidate the reaction mechanisms of the glass powder, in order to better identify its behavior in cementitious matrices. For comparison purposes, conventional supplementary materials are also included in the investigation. Several w/b ratios (0.35 ≤ w/b ≤ 0.65) were considered in a first series of concretes. The results obtained from these investigations, in terms of compressive strength, penetrability of chloride ions and water permeability, are in a good agreement with the trend previously observed for w/b=0.55 and w/b=0.40. In a second series of concretes, three w/b ratios (0.55, 0.45 and 0.40) were selected for in-depth investigations of transport properties and accelerated aging tests, i.e., carbonation and corrosion. The sulfate resistance was also evaluated on mortar specimens. The main results showed a slight increase of total porosity and gas permeability of concretes in presence of glass powder (or class F fly ash). However, water permeability and other transport properties involving chlorides are strongly reduced in presence of glass powder (or the other conventional additions). Low penetrability of concrete in presence of glass powder, regardless of the w/b ratio, was well demonstrated with results of the initiation of corrosion test induced by chloride. However, a similar positive effect of glass powder was not observed with the progression of the initial accelerated carbonation front. Moreover, concrete incorporating glass powder develops relatively low compression strength at early age (similarly as fly ash and unlike slag). However, a combination of glass powder with metakaolin provided very good synergetic effects and contributed in improving the early-age resistance. Finally, this study showed that the effects of glass powder on concrete properties are generally similar to those of class F fly ash. Overall, the results of this study highlight the significant contribution of the glass powder in improving the resistance of concrete against the external attacks and promote the large-scale use of this product in building materials.
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Tout, Firas. "Étude expérimentale des éléments structuraux multi-matériaux collés sollicités en flexion : effet du fluage, fatigue et durabilité." Phd thesis, Université Claude Bernard - Lyon I, 2014. http://tel.archives-ouvertes.fr/tel-01064338.
Abstract:
Ce travail porte sur la compréhension du comportement en flexion, statique instantané, en fatigue et en fluage des structures multi matériaux du génie civil, constituées d'acier et de béton et assemblées par un adhésif de type époxy. L'analyse et la résolution du problème posé se feront à deux échelles : au niveau de l'interface et à l'échelle d'un élément de structure. De plus, l'attention sera tout particulièrement portée sur le comportement au cours du temps (fluage, relaxation, retrait...), la fatigue et la durabilité sous différents environnements. La première étape consiste à mener une analyse expérimentale sur la caractérisation de la connexion acier-béton, à l'échelle de l'interface, en vue de repérer les principaux facteurs influençant leur comportement mécanique. Pour cela, L'essai push out, analogue à celui utilisé pour caractériser les connecteurs des ponts mixtes, a été plus particulièrement utilisé. Des essais de vieillissement accéléré par immersion dans un bain d'eau chaude ont été réalisés. Ils n'ont pas diminué la contrainte de cisaillement moyenne à rupture de façon significative mais ont en revanche modifié le mode de ruine qui devient mixte (adhésif et cohésif dans la colle). Cette modification est à la fois due au primaire et à l'adhésif lui-même dont les performances intrinsèques diminuent avec le vieillissement. A l'échelle d'un élément de structure, nous avons enrichi les données expérimentales existantes sur le comportement instantané des poutres mixtes acier-béton collées avec la réalisation de 7 essais de flexion avec deux modes de sollicitation (flexion 3 et 4 points). Ces essais nous donnent une base solide pour nos essais en fatigue et sous fluage. On constate que le mode de ruine est mieux prédit en se basant sur une comparaison entre la contrainte de cisaillement dans les poutres avec les contraintes de cisaillement limite déduites des essais push-out. Cette conclusion montre la pertinence des essais push-out dans l'objectif de les prendre comme critère de dimensionnement. Aussi, et contrairement aux travaux antérieurs, nous pouvons conclure que la contrainte moyenne de cisaillement à l'interface entre le béton et l'acier est supérieure à la résistance en traction du béton utilisé. Pour le comportement à long terme, trois poutres ont été testées sous charge cyclique pour plus de 2 million de cycles et à plusieurs niveaux de charge. Une autre poutre a subi une charge constante pendant 7 mois pour étudier l'influence de fluage sur ce type de structure. Après les essais de fatigue et fluage, le comportement des poutres est analogue à celui des poutres de référence. Nous avons toujours une ruine par rotule plastique et non par cisaillement du joint de colle ce qui confirme sa bonne résistance vis-à-vis ces deux phénomènes
Books on the topic "Mixture durability":
1
Guidelines for concrete mixtures containing supplementary cementitious materials to enhance durability of bridge decks. Washington, D.C: Transportation Research Board, 2007.
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Guidelines for Concrete Mixtures Containing Supplementary Cementitious Materials to Enhance Durability of Bridge Decks. Washington, D.C.: Transportation Research Board, 2007. http://dx.doi.org/10.17226/23181.
Book chapters on the topic "Mixture durability":
1
Hasan, Nausherwan. "Concrete Mixture Design." In Durability and Sustainability of Concrete, 37–61. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-51573-7_2.
2
Athira, S., and G. S. Manju. "Effect of Modification on Coir Fiber in Durability and Shear Parameters in Flyash Soil Mixture." In Lecture Notes in Civil Engineering, 155–66. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-1831-4_14.
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Airey, Gordon D. "Durability of bituminous mixtures." In Construction Materials, 731–40. Fifth edition. | Boca Raton : CRC Press, [2017]: CRC Press, 2017. http://dx.doi.org/10.1201/9781315164595-63.
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Alexander, Mark, Arnon Bentur, and Sidney Mindess. "Design of concrete mixtures for durability." In Durability of Concrete, 263–78. Boca Raton : CRC Press, [2017] | Series: Modern concrete technology series: CRC Press, 2017. http://dx.doi.org/10.1201/9781315118413-9.
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Quercia, G., P. Spiesz, and H. J. H. Brouwers. "Effects of Nano-silica (NS) Additions on Durability of SCC Mixtures." In Durability of Reinforced Concrete from Composition to Protection, 125–43. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-09921-7_12.
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White, Greg, and Kayl Fergusson. "Exploring the Durability Specification of Coarse Aggregate Used in Airport Asphalt Mixtures." In Sustainable Civil Infrastructures, 207–24. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-62586-3_13.
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Kolay, Prabir K., Salman Sulaiman, Sanjeev Kumar, and Vijay K. Puri. "Freeze-Thaw Durability of Air-Entrained Concrete Incorporating Natural and Recycled Concrete Aggregate Mixtures." In Materials for Sustainable Infrastructure, 185–96. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-61633-9_11.
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Lesueur, Didier, Pierre Métais, Patrick Pibis, Samyr El Bedoui, Hervé Ruat, Stéphane Bouron, and Ferhat Hammoum. "Improving the Durability of Asphalt Mixtures with Hydrated Lime: Field Results from Recent French Sections." In RILEM Bookseries, 1047–53. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-46455-4_133.
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Weisenberger, Loring A., and Yahya Hodjat. "Investigation of the Effects of Mixtures of Dissimilar Engine Coolant Inhibitor Chemistries on Automotive Water Pump Durability." In ASTM Symposium on Global Testing of Extended Service Engine Coolants and Related Fluids, 217–28. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2014. http://dx.doi.org/10.1520/stp155620130071.
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Xu, Feng, and Qian Liu. "China: Community Policing, High-Tech Surveillance, and Authoritarian Durability." In Covid-19 in Asia, 27–42. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197553831.003.0002.
Abstract:
This chapter discusses China’s emergency responses to the Covid-19 pandemic. China’s emergency responses reflected a mixture of mass mobilization of political, economic, and social resources, as in war times. However, China’s initial mishandling of the Covid-19 outbreak, primarily at local levels, damaged the world’s trust. China sought world leadership through global propaganda campaigns and “mask diplomacy.” The chapter then investigates China’s legal and social prevention and control mechanisms, most notably community policing and surveillance technology. It also considers serious challenges that emerged in the early stages of the pandemic. China faced numerous challenges to its governance and state capacities, in resuming its economy, getting people employed, and ensuring people’s livelihood in an international context where the US–China relationship is fraught with tension.
Conference papers on the topic "Mixture durability":
1
Kevern, John T., and Vernon R. Schaefer. "Mixture Proportioning Considerations for Improved Freeze-Thaw Durability of Pervious Concrete." In 10th International Symposium on Cold Regions Development. Reston, VA: American Society of Civil Engineers, 2013. http://dx.doi.org/10.1061/9780784412978.046.
2
Seo, Woo-Jin, Dae-Wook Park, Hai Viet Vo, and Hyeok-Jung Kim. "Improvement of Durability of Recycled Asphalt Mixture Using Developed Anti-Stripping Agents." In Fourth International Conference on Sustainable Construction Materials and Technologies. Coventry University, 2016. http://dx.doi.org/10.18552/2016/scmt4d182.
3
Zak, Josef, Jan Suda, Petr Mondschein, Otakar Vacin, and Svatopluk Stoklasek. "Asphalt Binder Modification Technologies and Its Influence on Mixture Durability with Regard to Fatigue Resistance." In Annual International Conference on Architecture and Civil Engineering. Global Science & Technology Forum (GSTF), 2015. http://dx.doi.org/10.5176/2301-394x_ace15.19.
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Suciu, Claudiu Valentin. "Experimental Investigations on the Nano-Damping Durability." In 2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2008. http://dx.doi.org/10.1115/micronano2008-70018.
Abstract:
Connected to the nano-technological development, solid-liquid interfaces have been used to dissipate surface energies, in systems where the solid is liquid-repellent. Such interfaces are able to store, release or transform the mechanical energy. For instance, some modified silicas and zeolites in association with water have been used to build efficient ecological dampers and springs. Regarding this attractive kind of storage and loss of energy, some practical aspects, such as the endurance limits need to be clarified, and measures to augment the nano-damping durability to values required by usual machine elements (106−107 working cycles) await validation. Thus, in this work endurance tests are performed on nano-porous silica gel micro-particles by using a compression-decompression chamber. When the colloidal mixture of water and silica gel was supplied directly into the test chamber, the nano-damping performances abruptly reduced at augmentation of the number of working cycles due to the colloid leakage at the seals. Such severe leakage occurred since the clearance between the piston and cylinder (hundreds of microns), prescribed by the seals makers, was one order of magnitude larger than the diameter of silica gel particles (tens of microns); accordingly, a few layers of silica gel penetrated the gap, producing damage by abrasive wear of the seals and even of the piston surface during about 105 working cycles. In order to augment the nano-damping durability, colloidal mixture of water and silica gel is introduced inside of a tank that is separated by micro-filters from the main cylinder, in which only water is supplied. One discusses the influence of filtration on the nano-damping performances and the variation of durability versus the ratio of the filter pore’s diameter to the mean size of the silica gel particles. During a few working cycles the silica gel grains are not damaged, since the uniform pressure distribution in the liquid surrounding the particles prevent them from premature fracture, even at high-pressurization. However, silica gel grains that undergo gradually fatigue fracture are able to pass the filter and then, to escape at the test chamber seals; this produces a continuous reduction of the silica gel quantity inside of the pressurization chamber and accordingly, a proportional reduction of dissipation. On a logarithmic scale, a slight linear decreasing of the damping occurs until a critical number of working cycles; this is followed by an abrupt linear reduction of dissipation, with a slope that decreases when the diameter of the filter orifices is diminished. Despite the undesired decreasing of the nano-damping performances at augmentation of the number of working cycles, using appropriate filters the durability can be extended to reach the required life of an actual machine element.
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Rudrapatna, Nagaraja S., Richard R. Bohman, Jonathan K. Anderson, Rudolph Dudebout, and Richard Hausen. "The Influence of Manufacturing Tolerances on Swirler Durability." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-26058.
Abstract:
Jet fuel flowing through the fuel injector is atomized and then mixed with high temperature compressed air flowing through the swirler to create a combustible mixture inside a gas turbine combustor. Individual geometric and flow features are carefully tuned at a component level to deliver optimum combustion performance. In a critical interface such as the fuel injector and swirler, manufacturing tolerances not only have an impact on combustor performance and operability but also on durability, as the relative position of the fuel injector to the swirler significantly impacts the swirler temperature. This paper studies the influence of manufacturing tolerances on component assembly and the resulting impact on swirler temperature. The oxidation damage mechanism of the swirler is used as a measure to assess swirler durability. A Pareto chart of the effect of manufacturing tolerances on metal temperature is used to highlight the key influencing parameters. Probability distribution associated with manufacturing tolerances is gathered with Monte Carlo simulation to guide the design.
6
Gao, Guohua, Weidong Huang, and Chuanhai Li. "Experimental Study on Durability of Hot Asphalt Mixture in Bridge Deck Pavement Based on Uniform Design." In 20th COTA International Conference of Transportation Professionals. Reston, VA: American Society of Civil Engineers, 2020. http://dx.doi.org/10.1061/9780784482933.154.
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Salehi, Saeed. "Applicability of Geopolymer Materials for Well P&A Applications." In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-62351.
Abstract:
Previous research on application of geopolymers in oil/gas wells is mainly unsuccessful due to failure to achieve a reasonable thickening time. This study presents geopolymer composite mixtures that have high compressive and shear bond strength, enhanceed thickening time, high durability, and reasonable shrinkage. Class F fly ash geopolymers are used for developing samples with different mix designs in this work. Class H Portland cement is used as a controller on all the tests conducted in this work. Tests conducted in this research include: unconfined compressive strength (UCS), shear bond strength, thickening time, and durability tests. Results indicate temperature as a crucial factor affecting the thickening time of geopolymer mix slurry. More than four hours thickening time is achieved by optimizing mix design and applying a developed mix of superplasticizer and retarder. UCS testing indicates a high compressive strength after one and fourteen days of curing for geopolymer mixtures. More than 6000 psi strength is achieved in long term (28 days curing). This indicates strength gained over time, for geopolymer mixture, where strength retrogression effects are observed for Portland cements. Results also reveal higher shear bond strength for Geopolymer mix, which can better tolerate de-bonding issues. Additionally, more ductile material behavior and higher fracture toughness, were observed for optimum geopolymer mixes. Final observations confirm applicability of these materials for oil and gas well cementing with circulating temperatures up to 300°F.
8
Scholl, Fino, Denis Neher, Maurice Kettner, Philipp Hügel, Heiko Kubach, and Markus Klaissle. "Development and Analysis of a Controlled Hot Surface Ignition System for Lean Burn Gas Engines." In ASME 2012 Internal Combustion Engine Division Spring Technical Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ices2012-81059.
Abstract:
Spark ignition constitutes the most common way of mixture inflammation for gas engines of CHP units (combined heat and power). However, spark plug durability is limited due to spark erosion. High maintenance costs as a result of frequent spark plug replacements are the consequence. Beside the durability aspect, the inflammation of lean mixtures makes high demands on the inflammation process itself. Due to the small reactive mixture volume, the level of air-fuel ratio as well as the efficiency increase is limited. The ignition by means of a hot surface enables an increase of the reactive mixture volume and, as a result, an enhancement of the lean burn limit. A hot surface ignition (HSI) system was developed for stationary lean burn operation in due consideration of low manufacturing costs and electrical characteristics that allow a reliable control of the ignition timing. The main component of the inflammation element is a pin-shaped glow plug, whose temperature can be regulated by adjusting the electrical power. Due to external influences such as fluctuating ambient pressure and gas quality a control unit is essential for securing an optimal combustion phasing of the engine. Several designs of hot surface ignition, including passive prechamber and shielded versions, were tested on a single cylinder test bed engine operating with a homogeneous air-petrol mixture. The engine tests were accompanied by 3D flow simulations. The trials showed that the power consumption, and hence the temperature of the hot surface, as well as the flow conditions around the glow plug have a strong influence on the ignition timing. Furthermore, a strong correlation between the mean combustion chamber temperature and combustion phasing became evident. Based on this coherence, it was possible to develop a closed-loop control that adjusts the combustion phasing by controlling the combustion chamber temperature at a stationary operating point. The shielded inflammation element stood out to be the target-aiming version of hot surface ignition. It is characterised by an accelerated inflammation which allows reducing the cycle-to-cycle variations compared to prechamber spark ignition and, hence, to enhance the lean burn limit. As a result, a significant improvement of the efficiency-NOx trade-off is possible. The obtained results provide the basis for further trials on a gas engine CHP module operating with natural gas.
9
Eggerstedt, Kyle, and Xia Wang. "Experimental Investigation of Biomass Pellets and Pelletizing Process Using Hardwood and Switchgrass." In ASME 2014 8th International Conference on Energy Sustainability collocated with the ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/es2014-6558.
Abstract:
Biomass fuel has been utilized as a renewable energy resource to replace or supplement fossil fuels. Combustion characteristics of biomass affect the utilization of biomass pellets. Activation energy, ash content, energy content, moisture content, density, and durability are a few parameters that are analyzed for ideal combustion. An ideal fuel can be created through analyzing multiple biomass materials and pelletizing procedures. The objective of this research is to improve biomass performance by investigating its pelleting parameters and the related combustion characteristics. A lab scale pelletizing process was developed with the pelletizing conditions being 150°C for 150 seconds under a pressure of 4500 psi. A total of 45 different types of pellets with a diameter of 2.5cm and a thickness of 5mm were created using the new pelletizing process. They had five different material mixtures (100% hardwood (HW), 75/25hardwood/switchgrass (HS), 50/50HS, 25/75HS, and 100% switchgrass (S)), three different original moisture contents (15%, 20%, and 25%), and 3 different amounts of binder (1/6, 1/12, and 0). Trends of the combustion characteristics to pelletizing process parameters were found. When the material mixture changes from pure hardwood to pure switchgrass, both activation energy decreases while ash content increases. When the binder decreases, activation energy increases as well as ash content while both energy content and durability decrease.
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Wawrzeńczyk, Jerzy, Agnieszka Molendowska, and Adam Kłak. "Quantitative assessment of aggregate segregation of hardened self compacted concrete based on 2D image analysis." In The 13th international scientific conference “Modern Building Materials, Structures and Techniques”. Vilnius Gediminas Technical University, 2019. http://dx.doi.org/10.3846/mbmst.2019.126.
Abstract:
Self-compacting concrete developed as a material that does not need vibration for compaction has been increasingly being used in routine practice. Successful application of self-compacting concrete (SCC) is difficult to achieve due to increased flowability of the concrete mixture. Segregation of aggregate is one of the major problems during construction and ultimately influences the strength and durability of SCC. A fresh self-compacting concrete with poor segregation resistance can lead to a nonuniform distribution of coarse aggregates in the concrete volume, contributing to blockage of concrete flow, and nonuniform mechanical properties and durability at the hardened concrete. The article presents the unique method for quantitative assessment of aggregate segregation in hardened self-compacted concrete. A digital image analysis procedure using original lighting microscope equipment has been placed to investigate the concrete segregation behavior. The photographs of concrete specimen surfaces were taken to calculate measurements of aggregate volume in concrete. The research results showed that the originally developed attachment and unique aggregate segregation assessment method are useful in laboratory tests and could be used in the on-site application.
Reports on the topic "Mixture durability":
1
Hekmatfar, Ali, Rebecca McDaniel, Ayesha Shah, and John Haddock. Optimizing Laboratory Mixture Design as It Relates to Field Compaction to Improve Asphalt Mixture Durability. Purdue University, December 2015. http://dx.doi.org/10.5703/1288284316010.
2
Rahman, Mohammad, Ahmed Ibrahim, and Riyadh Hindi. Bridge Decks: Mitigation of Cracking and Increased Durability—Phase III. Illinois Center for Transportation, December 2020. http://dx.doi.org/10.36501/0197-9191/20-022.
Abstract:
Early-age cracking in concrete decks significantly reduces the service life of bridges. This report discusses the application of various concrete mixtures that include potential early mitigation ingredients. Large-scale (7 ft × 10 ft) experimental bridge prototypes with similar restraint conditions found in actual bridges were poured with different concrete mixtures to investigate mitigation techniques. Portland cement (control), expansive Type K cement, internally cured lightweight aggregate (LWA), shrinkage-reducing admixture (SRA), and gypsum mineral were investigated as mitigating ingredients. Seven concrete mixtures were prepared by using individual ingredients as well as a combination of different ingredients. The idea behind combining different mitigating techniques was to accumulate the combined benefit from individual mitigating materials. The combined Type K cement and LWA mixture showed higher concrete expansion compared with mixtures containing Portland cement, Type K cement, LWA, and SRA in the large-scale experimental deck. Extra water provided by LWA significantly enhanced the performance of Type K cement’s initial expansion as well as caused larger total shrinkage over the drying period. A combination of Type K cement and gypsum mineral showed insignificantly higher expansion compared with the individual Type K mixture. Overall, the experimental deck containing SRA showed the least total shrinkage compared with other mixtures. Finite-element modeling was performed to evaluate and predict concrete stress-strain behavior due to shrinkage in typical bridges. A parametric study using finite-element analysis was conducted by altering the structure of the experimental deck. More restraint from internal reinforcement, less girder spacing, larger girder flange width, and more restrictive support conditions increased the concrete tensile stress and led to potential cracking in the concrete deck.
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Piepel, G., T. Redgate, and P. Masuga. Mixture models versus free energy of hydration models for waste glass durability. Office of Scientific and Technical Information (OSTI), March 1996. http://dx.doi.org/10.2172/219295.
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Haddock, John E., Reyhaneh Rahbar-Rastegar, M. Reza Pouranian, Miguel Montoya, and Harsh Patel. Implementing the Superpave 5 Asphalt Mixture Design Method in Indiana. Purdue University, 2020. http://dx.doi.org/10.5703/1288284317127.
Abstract:
Recent research developments have indicated that asphalt mixture durability and pavement life can be increased by modifying the Superpave asphalt mixture design method to achieve an in-place density of 95%, approximately 2% higher than the density requirements of conventionally designed Superpave mixtures. Doing so requires increasing the design air voids content to 5% and making changes to the mixture aggregate gradation so that effective binder content is not lowered. After successful laboratory testing of this modified mixture design method, known as Superpave 5, two controlled field trials and one full scale demonstration project, the Indiana Department of Transportation (INDOT) let 12 trial projects across the six INDOT districts based on the design method. The Purdue University research team was tasked with observing the implementation of the Superpave 5 mixture design method, documenting the construction and completing an in-depth analysis of the quality control and quality assurance (QC/QA) data obtained from the projects. QC and QA data for each construction project were examined using various statistical metrics to determine construction performance with respect to INDOT Superpave 5 specifications. The data indicate that, on average, the contractors achieved 5% laboratory air voids, which coincides with the Superpave 5 recommendation of 5%. However, on average, the as-constructed mat density of 93.8% is roughly 1% less than the INDOT Superpave 5 specification. It is recommended that INDOT monitor performance of the Superpave 5 mixtures and implement some type of additional training for contractor personnel, in order to help them increase their understanding of Superpave 5 concepts and how best to implement the design method in their operation.
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Wei, Fulu, Ce Wang, Xiangxi Tian, Shuo Li, and Jie Shan. Investigation of Durability and Performance of High Friction Surface Treatment. Purdue University, 2021. http://dx.doi.org/10.5703/1288284317281.
Abstract:
The Indiana Department of Transportation (INDOT) completed a total of 25 high friction surface treatment (HFST) projects across the state in 2018. This research study attempted to investigate the durability and performance of HFST in terms of its HFST-pavement system integrity and surface friction performance. Laboratory tests were conducted to determine the physical and mechanical properties of epoxy-bauxite mortar. Field inspections were carried out to identify site conditions and common early HFST distresses. Cyclic loading test and finite element method (FEM) analysis were performed to evaluate the bonding strength between HFST and existing pavement, in particular chip seal with different pretreatments such as vacuum sweeping, shotblasting, and scarification milling. Both surface friction and texture tests were undertaken periodically (generally once every 6 months) to evaluate the surface friction performance of HFST. Crash records over a 5-year period, i.e., 3 years before installation and 2 years after installation, were examined to determine the safety performance of HFST, crash modification factor (CMF) in particular. It was found that HFST epoxy-bauxite mortar has a coefficient of thermal expansion (CTE) significantly higher than those of hot mix asphalt (HMA) mixtures and Portland cement concrete (PCC), and good cracking resistance. The most common early HFST distresses in Indiana are reflective cracking, surface wrinkling, aggregate loss, and delamination. Vacuum sweeping is the optimal method for pretreating existing pavements, chip seal in particular. Chip seal in good condition is structurally capable of providing a sound base for HFST. On two-lane highway curves, HFST is capable of reducing the total vehicle crash by 30%, injury crash by 50%, and wet weather crash by 44%, and providing a CMF of 0.584 in Indiana. Great variability may arise in the results of friction tests on horizontal curves by the use of locked wheel skid tester (LWST) due both to the nature of vehicle dynamics and to the operation of test vehicle. Texture testing, however, is capable of providing continuous texture measurements that can be used to calculate a texture height parameter, i.e., mean profile depth (MPD), not only for evaluating friction performance but also implementing quality control (QC) and quality assurance (QA) plans for HFST.