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1
Abdulhussein, Faisal K., Zahraa F. Jawad, Qais J. Frayah, and ِAwham J. Salman. "Investigation of the Effect of Addition Nano-papyrus Cane on the Mechanical Properties of Concrete." Civil Engineering Journal 7, no. 2 (February 1, 2021): 226–35. http://dx.doi.org/10.28991/cej-2021-03091649.
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This paper investigates the effect of nano-papyrus cane ash as an additive on concretes’ mechanical and physical properties. Three types of concrete mixtures, 1:2:4, 1:1.5:3, and 1:1:2 were prepared for each mixture, nano-papyrus ash was added in five different dosages of 0.75, 1.5, 3, 4.5, and 6% by weight of cement; therefore, eighteen mixes would be studied in this work. Physical properties represented by dry density and slump were also measured for each mix. Moreover, to evaluate the mechanical properties development split tensile strength and compressive strength were obtained at age (7 and 28). Results manifested that the adding of nano ash developed the compressive strength and split tensile strength of concrete and the maximum enhancement recognized in the mixes with a content of 4.5% nano-papyrus in each studied mixture in this work. The slump test results indicated that the workability of concrete increased with adding nano-papyrus ash gradually with increasing nanoparticles' content. As well as, dry density was significant increased with nano-papyrus ratio; greater values were recorded in mixtures with 1.5-4.5% content of nano-papyrus. When comparing the concrete mixes used, it was found that the best results were obtained with 1:1:2 mixtures. This remarkable improvement in concrete properties considers the nano-papyrus is considered a cement economical and useful replacement for traditional construction material. Doi: 10.28991/cej-2021-03091649 Full Text: PDF
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Petrounias, Petros, Panagiota P. Giannakopoulou, Aikaterini Rogkala, Paraskevi Lampropoulou, Basilios Tsikouras, Ioannis Rigopoulos, and Konstantin Hatzipanagiotou. "Petrographic and Mechanical Characteristics of Concrete Produced by Different Type of Recycled Materials." Geosciences 9, no. 6 (June 19, 2019): 264. http://dx.doi.org/10.3390/geosciences9060264.
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This paper examined three different types of recycled materials, such as beer green glass, waste tile, and asphalt, which will be used in different mixtures in order to prepare concrete specimens and, more specifically, their effect on concrete strength and how the petrographic characteristics of various recycled materials influenced the durability of C25/30 strength class concrete. Particular emphasis was placed on the effect of artificial microroughness of glassy and smooth surfaces of recycled materials on their final concrete strength. The concrete strength values do not show great variance, but their limited differences have been qualitatively interpreted by a new promising petrographic methodology, including the study of the surface texture of the used aggregate materials. Concretes are produced with constant volume proportions, workability, mixing, and curing conditions while using different sizes of each aggregate type. The aggregates were mixed both in dry and water saturated states in concretes. Concretes that are made by a mixture of beer green glass with quartz primer, as well as of tile with quartz primer, presented the optimum possible results of the compressive strength.
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Pan, Changlin, and Thomas D. White. "Evaluation of Stripping for Asphalt Concrete Mixtures Using Accelerated Testing Methods." Transportation Research Record: Journal of the Transportation Research Board 1630, no. 1 (January 1998): 98–105. http://dx.doi.org/10.3141/1630-12.
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A laboratory study was conducted to determine the water sensitivity and rutting potential of asphalt mixtures. The two major tests included in the study were AASHTO T-283 and a laboratory wheel tracking device. AASHTO T-283 has been adopted in the Superpave system for evaluating mixture-stripping potential. The laboratory wheel tracking device was designed and fabricated to represent conditions associated with stripping, that is, moisture, high temperature, and a moving wheel load. Tests can be conducted with a hot and wet or a hot and dry environment. The objective of the study was to evaluate factors influencing bituminous mixture stripping potential. The laboratory wheel tests can simulate mixture stripping conditions as well as pavement loadings. Rutting potential with and without stripping in hot-wet and in hot-dry environments, respectively, can be determined independently. The difference in rutting for the two environmental conditions indicates the magnitude of rutting associated with stripping. Test results show the potential for the wheel tracking device to evaluate the rutting and stripping of asphalt mixtures under various temperature and moisture conditions. In a comparison of two Indiana No. 11 surface mixtures, limestone and dolomite, the limestone mix has a lower susceptibility to rutting than that of the dolomite mix at 50 and 60°C. Moisture damage was shown to occur over a range of temperatures from room temperature to 60°C.
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Shkromada, Oksana, Tatiana Fotina, Roman Petrov, Liudmyla Nagorna, Olexandr Bordun, Marina Barun, Olena Babenko, Maksym Karpulenko, Taras Tsarenko, and Vyacheslav Solomon. "Development of a method of protection of concrete floors of animal buildings from corrosion at the expense of using dry disinfectants." Eastern-European Journal of Enterprise Technologies 4, no. 6(112) (August 31, 2021): 33–40. http://dx.doi.org/10.15587/1729-4061.2021.236977.
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Concrete floors are most commonly used in animal housing. However, the specific environment of livestock buildings (moisture, urine, disinfectants) has a negative effect on concrete and leads to its corrosion. The influence of chemical and physical factors on concrete is reinforced by the development of microorganisms, which quickly adapt and use concrete as a living environment. To reduce the influence of an aggressive environment on the concrete floor, an experimental mixture of dry disinfectants was proposed. The components of the disinfection mixture have been selected taking into account the safety for animals and humans. The TPD-MS method was used to determine the change in the chemical composition of concrete. To study the microstructure of concrete, the method of scanning electron microscopy was used. Microbiological studies revealed bacteria A. Thiooxidans, S. aureus, E. coli, S. enteritidis, S. Сholeraesuis, C. Perfringen and micromycetes of the genus Cladosporium, Fusariums, Aspergillus, which contribute to the development of biological corrosion of concrete in livestock buildings. The fact of the negative impact of concentrated disinfectants on the structure of concrete was also established. As a result of the studies carried out, it was proved that a mixture of dry components for disinfection exhibits antimicrobial properties to varying degrees to the strains of field isolates of bacteria and fungi isolated in a pig-breeding farm. It was found that when using the proposed mixture of dry disinfectants in the research room of the pigsty, the relative humidity decreases by 38.5 %; ammonia content – by 46.2 %; hydrogen sulfide – by 57.8 %; microbial bodies – by 74.7 %, compared with the control room. It has been experimentally proven that the proposed mixture of dry disinfecting components has hygroscopic and antimicrobial properties and is promising for use in livestock farms.
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Bastidas-Martínez, Juan Gabriel, Nicolás Infante Rodríguez-Joaquín, Hernán Darío Torres-Daza, Hugo Alexander Rondón-Quintana, and Juan Carlos Ruge-Cárdenas. "Behavior of a draining mixture composed by recycled concrete aggregates and rubberized asphalt concrete." Respuestas 25, no. 1 (January 1, 2020): 96–107. http://dx.doi.org/10.22463/0122820x.2418.
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Concrete waste is considered an environmental liability with a negative impact. However, this type of waste presents a high potential to be used as an alternative building material. Therefore, the present study aims to evaluate the applicability of substituting the conventional natural stone aggregate (CA) of a draining asphalt mixture (MD) by a recycled concrete aggregate (RCA). Firstly, RCA was physically characterized to be compared with the AC. Then, two MD mixtures were design with rubberized asphalt concrete (GCR by its spanish acronym): one using the conventional aggregate (control sample) and one with the RCA substituting entirely the CA. Experimental tests under monotonic load (indirect tensile strength - RTI) were conducted over the mixtures, as well as adhesion tests (susceptibility of RTI in wet and dry conditions and abrasion wear Cantabro). The results indicate that for MD mixtures with RCA, a higher content of asphalt is required than with CA. Additionally, it wasfound that the presence of higher asphalt content in MD-RCA mixtures increases its adhesion when compared with the control sample. Therefore, it can be concluded that the use the RCA for MD mixtures, in the proposed way, is technically and environmentally viable.
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Tůmová, Eva, and Rostislav Drochytka. "New Type of Industrial Floors with Secondary Raw Materials." Advanced Materials Research 645 (January 2013): 164–67. http://dx.doi.org/10.4028/www.scientific.net/amr.645.164.
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Dry shake screeds are characterized by high durability. It is a modern way of improving the mechanical and aesthetic properties of concrete floor surfaces. It is the so-called “wet-on-wet” method – i.e. a method of applying cement mixtures for floor screed. Stirred cement mixture is spread, in the prescribed thickness, onto the setting fresh cement mixture surface that was arranged and compacted before.
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Attia, Ahmed, Salim Guettala, and Rebih Zaitri. "Using mixture design method to optimizing concretes characteristics made with binary and ternary sands." World Journal of Engineering 18, no. 2 (January 13, 2021): 194–205. http://dx.doi.org/10.1108/wje-05-2020-0184.
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Purpose The purpose of this paper is to implement the mathematical models to predict concretes physico-mechanical characteristics made with binary and ternary sands using a mixture design method. It is a new technique that optimizes mixtures without being obliged to do a lot of experiments. The goal is to find the law governing the responses depending on mixture composition and capable of taking into account the effect of each parameter separately and in interaction between several parameters on the characteristics studied. Design/methodology/approach Mixture design method was used for optimizing concretes characteristics and studying the effects of river sand (RS), dune sand (DS) and crushed sand (CS) in combinations of binary system and ternary on workability, the compressive and flexural strengths of concretes at 7 and 28 days. A total of 21 mixtures of concrete were prepared for this investigation. The modeling was carried out by using JMP7 statistical software. Findings Mixture design method made it possible to obtain, with good precision, the statistical models and the prediction curves of studied responses. The models have relatively good correlation coefficients (R2 = 0.70) for all studied responses. The use of binary and ternary mixtures sands improves the workability and their mechanical strengths. The obtained results proved that concrete, based on binary mixture C15, presents the maximum compressive strength (MCS) on 28 day with an improvement of around 20%, compared to reference concrete (C21). For ternary mixtures, MCS on 28 day was obtained for the mixture C10 with an improvement of around 15% compared to C21. Increase in compressive strength during the progress of hydration reactions was accompanied by an increase in the flexural strength, but in different proportions. Originality/value The partial incorporation of DS (= 40%) in the concrete formulation can provide a solution for some work in the southern regions of country. In addition, the CS is an interesting alternative source for replacing 60% of RS. The concrete formulation based on local materials is really capable of solving the economic and technical problems encountered in the building field, as well as environmental problems. Local resources therefore constitute an economic, technological and environmental alternative.
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Fardin, Hedelvan Emerson, and Adriana Goulart dos Santos. "Roller Compacted Concrete with Recycled Concrete Aggregate for Paving Bases." Sustainability 12, no. 8 (April 14, 2020): 3154. http://dx.doi.org/10.3390/su12083154.
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This research aimed to investigate the mechanical and physical properties of Roller Compacted Concrete (RCC) used with Recycled Concrete Aggregate (RCA) as a replacement for natural coarse aggregate. The maximum dry density method was adopted to prepare RCC mixtures with 200 kg/m³ of cement content and coarse natural aggregates in the concrete mixture. Four RCC mixtures were produced from different RCA incorporation ratios (0%, 5%, 15%, and 30%). The compaction test, compressive strength, splitting tensile strength, flexural tensile strength, and modulus of elasticity, porosity, density, and water absorption tests were performed to analyze the mechanical and physical properties of the mixtures. One-way Analysis of Variance (ANOVA) was used to identify the influences of RCA on RCC’s mechanical properties. As RCA increased in mixtures, some mechanical properties were observed to decrease, such as modulus of elasticity, but the same was not observed in the splitting tensile strength. All RCCs displayed compressive strength greater than 15.0 MPa at 28 days, splitting tensile strength above 1.9 MPa, flexural tensile strength above 2.9 MPa, and modulus of elasticity above 19.0 GPa. According to Brazilian standards, the RCA added to RCC could be used for base layers.
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Yu, Li Ming, Zhe An Lu, Xiao Hui Yuan, and Hui Guo Chen. "Mixture Ratio Design of Inorganic Polymer Concrete and the Study of Expansive Performance." Applied Mechanics and Materials 357-360 (August 2013): 1142–47. http://dx.doi.org/10.4028/www.scientific.net/amm.357-360.1142.
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norganic polymer concrete of a new environment-friendly material has been the hot issue in engineering research so far. For this new material, the main job of the paper includes: we design mixture ratios of inorganic polymer concrete by ourselves, testing the concrete in the age periods of 3, 7, 28 d. The results indicate that this kind of material strength develops mainly in the first 3 d, the strength grows slowly in the later stage; the dry shrinkage of the configured concrete properties are measured, the curve of dry shrinkage shows that the dry shrinkage occurs mainly in the first 14 d and develops slowly in the late; And measure the expansion performance of the concrete member mixed the different categories expansive agent, the results show that the volume growth of mortar specimens to join HCSA expansion agent are obvious; Test results provide a certain basis for the inorganic polymer concrete of micro expansion.
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Samor, Zahraa Ahmed, and Saad Issa Sarsam. "Assessing the Moisture and Aging Susceptibility of Cold Mix Asphalt Concrete." Journal of Engineering 27, no. 2 (February 1, 2021): 59–72. http://dx.doi.org/10.31026/j.eng.2021.02.05.
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Laboratory experience in Iraq with cold asphalt concrete mixtures is very limited. The design and use of cold mixed asphalt concrete had no technical requirements. In this study, two asphalt concrete mixtures used for the base course were prepared in the laboratory using conventional cold-mixing techniques to test cold asphalt mixture (CAM) against aging and moisture susceptibility. Cold asphalt mixtures specimens have been prepared in the lab with cutback and emulsion binders, different fillers, and curing times. Based on the Marshal test result, the cutback proportion was selected with the filler, also based on the Marshal test emulsion. The first mixture was medium setting cationic emulsion (MSCE) as a binder, hydrated lime, and ordinary portland cement as a filler (7.95% MSCE + 2%HL + 3% OPC). The second mixture used was medium curing cutback (MC-250) as a binder and ordinary portland cement as a filler (5.18% MC 250 + 5% OPC). The indirect tensile strength (ITS) of the samples was measured at 25 ° C. It was found that the cold mix with the MSCE binder had a high ITS value relative to the cold mix with the cutback asphalt binder (MC-250). The dry mixture of MSCE ITS was approximately 3.77 times the dry mixture of MC-250. The MSCE wet mix was about 4.2 times the wet MC-250 mix. Tensile strength ratio result (TSR %) for the MSCE binder mix and the cutback MC-250 binder mix showed that the MSCE mix has a reasonable moisture resistance (77% ) compared to the MC-250 mix (69.2 %). The aging test and aging ratio result showed that asphalt binder oxidation has a significant effect on age-related pavement degradation as it changes the time-temperature relationship depending on the viscoelastic properties of the asphalt binder. The result clearly showed that the MSCE binder mix had a high resistance to aging (440 Kpa) compared to the cutback (MC-250) binder mix (110 Kpa). In contrast, the MSCE aging ratio (90 %) was higher than the MC-250 ratio (85 %).
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zedan, Adnan Jayed, Rizgar Ali Hummadi, and Sarah Abdullah Hussein. "Effect of Adding Mixture of (Concrete Waste and Asphalt Waste) on The Properties of Gypseous Soil." TJES Vol26 No.1 2019 26, no. 1 (March 2, 2019): 20–25. http://dx.doi.org/10.25130/tjes.26.1.03.
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Gypseous soil which is used is taken from Tikrit city in Salah Aldeen government and specially from Tikrit University from a depth (1.5-2)m, It’s type is sandy gravely with a small percentage of silt and clay while the percentage of gypsum is (34-36)%, The tests on soil is standard proctor compaction, direct shear, collapsibility and California bearing ratio. The number of samples is (70). The effect of adding concrete waste (2, 4, 6 and 8%) and waste of Asphalt mixture (2, 4, 6 and 8) % on dry soil, as well as the effect of mixture of the optimum percentages of both additions on the properties of gypseous soil, is the aim of the study. Adding concrete waste at optimum percentage (6)% causes an increase maximum dry density at (16)% and a decrease in optimum moisture content at (5)%. Whereas adding concrete mixture waste in its optimum percentage (2)% caused a decrease in maximum dry density values with an increase of optimum moisture content, and when adding mixture of optimum percentage of waste, an increase happened in the M.D.D.(14)% with a decrease in O.M.C. at (4)%. Adding the optimum percentage (8) % for both. Value of cohesion increases (100)% when adding concrete waste with an increase in the angle of internal friction (14)% and a decrease in collapsibility in a percentage of (90)%, while adding waste of asphalt mixture shows an increase in cohesion value (112)% with a decrease in the angle of internal friction (2)%and a decrease in collapsibility in a percentage of (90)%, when adding mixture of optimum percentages the value of cohesion increase (108)% with an increase in angle of internal friction (14)%and a decrease in collapsibility in a percentage of (91)%. Values of California Bearing Ratio in dry and soaked condition increases (49)% when adding (8)% of concrete wastes which is the optimum percentage, while adding waste of asphalt mixture causes a decrease in the value of C.B.R. and the optimum percentage is (2)% , but adding optimum percentages mixture of them causes an increase in values of (52)% in dry condition and (53)% in soaked condition.
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Vogel, Filip, Radoslav Sovják, Ondřej Holčapek, Libor Mařík, and Jiří Šach. "Experimental Study of Primary Lining Tunnel Concrete after Thirty Years of Operation." Applied Mechanics and Materials 732 (February 2015): 403–6. http://dx.doi.org/10.4028/www.scientific.net/amm.732.403.
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This article shows the acquisition and testing of concrete from tunnel primary lining. The main objective of this article was to describe the mechanical properties of primary lining tunnel concrete at higher age. The primary lining was made from dry mixture sprayed concrete. The primary lining concrete was in contact with the surrounding rock continuously. The surrounding rock could be dry or with ground water. Some surrounding rocks could produce a highly aggressive environment for concrete. The question was, whether the sprayed concrete is still in service after 30 years in this environment.
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Rajczyk, Jarosław, and Bogdan Langier. "Concrete Composite Properties with Modified Sodium Bentonite in Material Application Engineering." Advanced Materials Research 583 (October 2012): 154–57. http://dx.doi.org/10.4028/www.scientific.net/amr.583.154.
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Modern concrete technology requires the use of a large scale of different types of additives that modify the concrete’s properties of features. Often, complicated technical conditions impose the usage of concretes with certain properties. One such example is a mixture transported by gravitational methods using rain gutters. In this situation, it is required to have a concrete mixture that has a high degree of fluidity and does not undergo segregation, sedimentation or other modification of uniformity while in transit. When placing the additional requirement that the concrete must have a high water resistance; bentonites may be particularly useful. This paper presents the results of mechanical and physical properties of concrete with different concentrations of ground sodium bentonite. The particle size being from 30 to 60 nm was added as a dry ingredient together with the aggregate at 1, 2, 3 and 4% by weight of the cement. The ground sodium bentonite demonstrated significant changes in the characteristics of the fresh and hardened concrete, such as: consistency, strength and the amount of capillary pressure.
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SOUDAIS, P. R. N., J. S. CAMACHO, and G. A. PARSEKIAN. "Influence of transverse rebars on bond between steel reinforcement and cellular concrete with very low compressive strength." Revista IBRACON de Estruturas e Materiais 11, no. 3 (May 2018): 620–43. http://dx.doi.org/10.1590/s1983-41952018000300011.
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Abstract Cellular concrete is a lightweight concrete obtained by aerating agent, which produces air-voids into the mixture. This work deals with bond between cellular concrete and steel rebars. Pull-out tests of 4,2 mm diameter rebars partly immersed into concrete cylinders were made. Concrete unit weight variation and setting of a transverse rebar into the concrete cylinder center constitute the variables of the work. Three types of mixture were prepared: one without aerating agent (with a dry unit weight of 2255 kg/m3), and two with different aerating agent rates (with a dry unit weight equal to 1565 and 1510 kg/m3). The study revealed the large decrease of bond stress between 4,2 diameter rebars and cellular concrete, due to concrete unit weight reduction. Transverse rebar introduced into concrete cylinder center increased the ultimate pull-out force of the test: the gain of bond produced by the transverse rebar grew up when the cellular concrete unit weight had been reduced. Therefore, special anchorages (not exclusively straight), permitting bond improvement between cellular concrete and rebars could be a solution to improve the mechanical performance of cellular concrete.
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Nejati, Faezeh, and S. A. Edalatpanah. "Experimental investigation for the effect of fiber on the mechanical properties of light-weight concrete under dry and wet conditions." International Journal of Structural Integrity 11, no. 2 (August 23, 2019): 216–38. http://dx.doi.org/10.1108/ijsi-04-2019-0036.
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Purpose The purpose of this paper is to investigate the effect of steel and carbon fibers on the mechanical properties of light concrete in terms of tension strength, compressive strength and elastic modulus under completely dry and wet conditions. Design/methodology/approach In this study, the lightweight concrete made of Light Expanded Clay Aggregate (LECA) as coarse aggregate and sand as fine aggregate was used. To achieve a compressive strength of at least 20 MPa, microsilica was used 10 percent by weight of cement. In order to compensate for the reduction of tension strength of concrete, steel and carbon fibers were used with three volume ratio of 0.5, 1 and 1.5 percent in concrete. The results of concrete specimens were studied at the age of 7, 28, 42 and 90 days under controlled dry and wet conditions. Findings The results showed that the addition of steel and carbon fibers to the concrete mixture would reduce the drop in slump. Also, the use of steel and carbon fibers plays a significant role in increasing the tension strength of the specimens. Furthermore, the highest increase in tension strength of steel and carbon fiber samples was 83.3 and 50 percent, respectively, than the non-fibrous specimen when evaluated at 90 days of age. Moreover, the steel and carbon fiber increased the water absorption of the samples. Adding steel and carbon fibers to a lightweight concretes mixture containing LECA aggregates plays a significant role in increasing the modulus of elasticity of the samples. The highest increase in the elastic modulus of steel and carbon fibers was 18.9 and 35.4 percent, respectively, than the non-fibrous specimen at 28 days of age. Originality/value In this paper, the authors investigated the mechanical properties of steel fiber and carbon reinforced concrete. Also, according to the conditions of storage of samples and the age of concrete (day), the experiments were carried out on samples.
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Ivanov, L. A., L. D. Xu, E. S. Bokova, A. D. Ishkov, and S. R. Muminova. "Nanotechnologies: a review of inventions and utility models. Part V." Nanotechnologies in Construction A Scientific Internet-Journal 12, no. 6 (December 27, 2020): 331–38. http://dx.doi.org/10.15828/2075-8545-2020-12-6-331-338.
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The article provides an abstract review of patents. The results of creative activity of scientists, engineers and specialists, including inventions in the field of nanotechnology and nanomaterials, being implemented, allow achieving a significant effect in construction, housing and community services, and related sectors of the economy. For example, the invention «A method to produce dry construction mixtures» refers to manufacturing of building materials, in particularly, to manufacture of dry construction mixtures (DCM) by the method of joint mechanoactivation of cement and dolomite, with further modification of them with carbon nanostructures (CNT). The technical result of the given method of mixing CNT and main component of dry construction mixtures - cement – is that it makes possible to use microquantities (0.005%) of CNT in DCM. That allows decreasing product cost of obtained mixture. Moreover, due to increased strength, faster hardening of materials one can reduce consumption of these mixtures. That is additional factor affecting decrease of mixture product cost. The results obtained after application of mechanoactivation of basic mixture components were different practically by all indicators from the mixtures prepared by simple mixing. Compression strength and tensile strength increased by 10–15%, adhesion strength increased too. Along with increasing of strength characteristics such an important indicator of DCM as air permeability has decreased. Reduction of total volume of pores in dense structure of cement matrix caused dramatic slow-up of moisture diffusion rate. The specialists can also be interested in the following inventions in the area of nanotechnologies: a method of laser building-up welding for metal coatings, high RAP in WMA surface mixture containing nanoglass fibers, a device to apply nanoparticles of metal oxides on metal surface under normal conditions, multifunctional nanostructured additive for coatings, experimental assessment of cement mortar using nanooxide compounds, a composition for setting constructional layers of road pavements, a method to obtain composite films of nanofibers, nano-engineering of construction materials using molecular dynamics simulations, cast and self-compacting concrete mixture for cast-in-situ concrete and prefabricated reinforced units, a method to obtain photocatalyst based on nanotubular titanium dioxide et al
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Ning, Hai Long, Wen Feng Zhao, Jian Liu, Shao Peng Jiao, and Yi Xin Wang. "Effect of Recycled Coarse Aggregate on Recycled Concrete Properties and Study of Optimum Mixture Ratio." Applied Mechanics and Materials 487 (January 2014): 84–89. http://dx.doi.org/10.4028/www.scientific.net/amm.487.84.
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To study the effect of recycled coarse aggregate, water-cement ratio and mixture ratio on the physico-mechanical properties of recycled concrete, determine the finial optimum mixture ratio and physico-mechanical properties of recycled concrete with the optimum mixture ratio, physico-mechanical tests are done on recycled concrete and conventional concrete. Results show that with the replacement rate increasing of recycled coarse aggregate, the compressive strength and splitting tensile strength of recycled concrete increase and then decrease. It is feasible to develop the concrete with 100% replacement rate of recycled coarse aggregate. With an increase of recycled coarse aggregate replacement rate, dry shrinkage ratio of concrete increases gradually, but the increasing range has little effect on the concrete. The concrete strength of 28 days is linear with water-cement ratio with the correlation coefficient is 0.98763. Taking appropriate mix design, the physico-mechanical properties of recycled concrete will surpass or be equivalent to those of conventional concrete. Recycled concrete of the optimum mixing rate is the high strength with lower brittleness.
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Sivilevičius, Henrikas, and Valentinas Podviezko. "CONDITIONAL OPTIMIZATION MATHEMATICAL MODEL OF THE ASPHALT CONCRETE MIXTURE GRADING." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 8, no. 2 (June 30, 2002): 125–32. http://dx.doi.org/10.3846/13923730.2002.10531264.
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A new partial conditional optimization method which enables to select the best ratio of imported fillers not only while designing the composition of asphalt concrete mixture but also while adjusting the composition of the produced asphalt concrete mixture according to the actual quality of hot fractions is presented. The constructed mathematical model, algorithm and the solved task prove that irrespective of the number of fillers (from 2 to 7 and more) the ratio of their mass can be selected which enables to produce an asphalt concrete mixture which meets the requirements of the composition project best. The mass ratio λ of imported fillers A 1 and reclaimed dust A 2, which settled and accumulated in the dry purification equipment of an asphalt concrete plant presented in Regulations DAT.AD-96 was taken into account for the first time. Methodological scientific novelty and a possibility to apply it in practice can improve the control of asphalt concrete mixture production.
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Zakarka, Mindaugas, Šarūnas Skuodis, Giedrius Šiupšinskas, and Juozas Bielskus. "Compressive strength and thermal properties of sand–bentonite mixture." Open Geosciences 13, no. 1 (January 1, 2021): 988–98. http://dx.doi.org/10.1515/geo-2020-0289.
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Abstract Sand–bentonite mixtures are used in road embankments as a protective material for protecting underground high-voltage cables and utility pipelines supplying water and gas etc. The sand–bentonite mixtures provide benefits while laying high-voltage cables. The purpose of this study is to determine the proportions as well as mechanical and thermal properties of a dry-mixed sand–bentonite mixture and to investigate the suitability of such mixtures for installation around high-voltage underground power lines in road embankments. When selecting a sand–bentonite mixture, the following requirements must be ensured: the compressive strength must be greater than 0.5 MPa after 24 h; the thermal resistivity must be greater than 1.2 K m/W (thermal conductivity 0,833 W/(K m)); and the moisture content of the sand–bentonite mixture must be less than 13%. The following materials were used when selecting the bentonite mixture: bentonite, 0–4.0 mm fraction sand, cement (CEM I 42.5R), and water. In this study, six groups of samples were formed, in which the parts of concrete, sand, cement, and water were added in different proportions. The strength and thermal conductivity of the samples were analyzed. Studies about the use of bentonite around high-voltage cables have revealed the need for wet mixing of bentonite suspensions. The required thermal conductivity properties of the soil were not achieved by dry mixing. This method of mixing can be useful only in cases when the thermal conductivity of the mixed soil is not relevant, because the work can be continued after a day.
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Sun, Jing, Jing Shun Yuan, Xiao Hong Cong, and Hong Bo Liu. "Experimental Study on Quality Control of Moderate-Strength Commercial Concrete." Applied Mechanics and Materials 174-177 (May 2012): 460–63. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.460.
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For the quality control of commercial concrete, it is important to choose correct raw- material and mixture ratio. C40 and C50 concrete were prepared in dry and cold climate environment, using local raw materials and a large amount of fly ash. Specific researches were made about different kinds and dosage of superplasticizers on the slump of concrete, slump loss and the intensity of the impact. The results show that naphthalene series superplasticizer JK-2 and 30% of fly ash can ensure that slump of the mixture concrete reach more than 180mm, slump loss is less than 30mm in an hour, strength of hardened paste will not be reduced, and concrete can be prepared with low costs.
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Qin, Hong Gen, Shuai Shuai Geng, Chao Ming Pang, and You Hua Tao. "Preparation and Mixture Ratio Design of Foam Concrete with Lightweight Tailings." Applied Mechanics and Materials 665 (October 2014): 172–78. http://dx.doi.org/10.4028/www.scientific.net/amm.665.172.
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In this paper, the preparation technology and improved the mixture ratio design method of foam concrete with lightweight tailings have been studied. Based on the review, the following research needs have been identified: (i) to calculate the amount of lightweight tailings by the binder materials content, (ii) to calculate additional water by the water absorption of lightweight tailings saturated surface dry condition, (iii) to calculate foam stabilizer content by the weight of foaming agent. Foam should be measured by volume. By testing the wet density of foam concrete paste to accurately control the amount of foam. The foam concrete mixed with a certain amount of lightweight tailings not only can significantly reduce the content of cement, reduce cost, but also can improve the performance of foam concrete.
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Hong, Se-Hee, Jin-Seok Choi, Jaehoon Lee, and Young-Soo Yoon. "Optimal Mix Design and Quality Properties of 50 MPa Self-Consolidating Lightweight Concrete." Journal of the Korean Society of Hazard Mitigation 20, no. 6 (December 31, 2020): 135–42. http://dx.doi.org/10.9798/kosham.2020.20.6.135.
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In this study, basic data were used to quantitatively determine the initial properties of self-consolidating lightweight concrete by analyzing various characteristics, such as air content, workability, segregation resistance, filling capacity, air/dry density, and strength according to the incorporating ratio of lightweight aggregate. With the exception of Mixture (LF75-LC100) that uses 100% lightweight coarse aggregate (LC) and 75% lightweight fine aggregate (LF), all the mixtures satisfied the performance criteria for workability, segregation resistance, and filling capacity, as suggested in the JSCE, and air/dry density, as suggested in the Concrete Standard Specification. The compressive strength of all the variables, except the LF75-LC100, was measured to be at least 50 MPa, but the strength decreased in a manner similar to that depicted in previous research when LC was incorporated. The results of the above experiments indicated that 100% of the LC and 50% of the LF was the optimal mix for self-consolidating lightweight concrete.
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Goberis, Stasys, and Valentinas Antonovič. "REFRACTORY GUNITE AND REFRACTORY CONCRETES COMPACTED USING VARIOUS METHODS/KAITRAI ATSPARUS TORKRETBETONIS IR KITAIS BŪDAIS SUTANKINTI BETONAI." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 2, no. 7 (September 30, 1996): 24–29. http://dx.doi.org/10.3846/13921525.1996.10531651.
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The aim of these investigations is to develop refractory gunite using local and waste materials available in Lithuania, to investigate its physical and mechanical properties and compare them with the same density and composition concrete compacted by vibration and ramming methods. In this work light (vermiculite, expanded fire clay, diatomite) and heavy (shamotte) aggregates with aluminium cement as binding material were used. The concrete samples (7×7×7 cm) were fired at various temperatures from 20°C to 1100°C. Five types of refractory gunites with different dry mixtures having a bulk density from 850 to 1500 kg/m3 have been developed. It was shown that concrete cold crushing strength depends on dry mixture bulk density and firing temperature: heavy concrete samples compacted by vibration and ramming methods are stronger, while light concrete samples made by gunning are better. The influence of temperature decreases the strength characteristics, which was confirmed by ultrasonic impulse velocity measurement results. An estimation of water requirements for concrete sample production various compacting methods is given. It was found that gunite water requirements are substantially lower than for rammed or vibrated concrete. Newly developed refractory gunite was used in furnaces as lining in an exhaust flue at Mažeikiai Oil Refinery.
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Balbo, J. T. "Relations between indirect tensile and flexural strengths for dry and plastic concretes." Revista IBRACON de Estruturas e Materiais 6, no. 6 (December 2013): 854–74. http://dx.doi.org/10.1590/s1983-41952013000600003.
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Indirect tensile strength is not usually used for concrete mixtures proportioning and its technological control; flexural strength tests under third point loads arrangement are the pattern for such goals. Indeed, neither of such tests have the capability to set up the actual strength of a concrete slab since its response is under plane stress state. A critical review of the basic concepts on both kinds of tests allows foreseeing its limitations as well as how to overcome such shortcomings. At last correlations between the two kinds of tensile strength are presented considering dry and plastic concretes typically applied on paving, corroborating to former results achieved for plastic concretes.
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Zhang, Li Juan, Yi Dong Xu, Lei Pan, Bing Bing Wang, and Chi Lou. "Cracking Risk Appraisal of High Performance Recycled Pavement Concrete and its Application." Advanced Materials Research 382 (November 2011): 256–59. http://dx.doi.org/10.4028/www.scientific.net/amr.382.256.
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Based on the technology of high performance concrete, high performance recycled pavement concrete (HPRPC) were developed by double -mixture of fly ash and superplasticizer. The dry shrinkage and plastic shrinkage cracking evaluation test were conducted. As is shown by the results, the compressive strength of HPRPC at 28d are exceed in 60MPa and dry shrinkage at 120d are less than 500με. By contrast, the cracking -resistant performance of HPRPC-7 is superior to that of HPRPC-2.
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Sharafutdinov, Eldar, Chang-Seon Shon, Dichuan Zhang, Chul-Woo Chung, Jong Kim, and Saltanat Bagitova. "Frost Resistance Number to Assess Freeze and Thaw Resistance of Non-Autoclaved Aerated Concretes Containing Ground Granulated Blast-Furnace Slag and Micro-Silica." Materials 12, no. 24 (December 11, 2019): 4151. http://dx.doi.org/10.3390/ma12244151.
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Aerated concrete (AC), such as cellular concrete, autoclaved aerated concrete (AAC), and non-autoclaved aerated concrete (NAAC), having excellent insulation properties, is commonly used in buildings located in cold regions, such as Nur-Sultan in Kazakhstan, the second coldest capital city in the world, because it can contribute to a large energy saving. However, when the AC is directly exposed to the repeated freeze and thaw (F-T) cycles, its F-T resistance can be critical because of lower density and scaling resistance of the AC. Moreover, the evaluation of the F-T resistance of the AC based on the durability factor (DF) calculated by using the relative dynamic modulus of elasticity may overestimate the frost resistance of the AC due to the millions of evenly distributed air voids in spite of its weak scaling resistance. In the present study, the F-T resistance of NAAC mixtures with various binary or ternary combinations of ground granulated blast-furnace slag (GGBFS) and micro-silica was assessed mainly using the ASTM C 1262/C1262M-16 Standard Test Method for Evaluating the Freeze-Thaw Durability of Dry-Cast Segmental Retaining Wall Units and Related Concrete Units. Critical parameters to affect the F-T resistance performance of the NAAC mixture such as compressive strength, density, water absorption, air–void ratio (VR), moisture uptake, durability factor (DF), weight loss (Wloss), the degree of saturation (Sd), and residual strength (Sres) were determined. Based on the determined parameter values, frost resistance number (FRN) has been developed to evaluate the F-T resistance of the NAAC mixture. Test results showed that all NAAC mixtures had good F-T resistance when they were evaluated with DF. Binary NAAC mixtures generally showed higher Sd and Wloss and lower DF and Sres than those of ternary NAAC mixtures. It was determined that the Sd was a key factor for the F-T resistance of NAAC mixtures. Finally, the developed FRN could be an appropriate tool to evaluate the F-T resistance of the NAAC mixture.
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Setiono, Joko Setiono, Agus Suhardono, and Johanes Asdhi Purwanto. "PASIR VULKANIK SEBAGAI BAHAN STABILITAS CAMPURAN GENTING BETON (STUDI EXSPERIMEN GRADASI PASIR GUNUNG KELUD PADA RADIUS 200 KM DI KOTA CARUBAN)." PROKONS Jurusan Teknik Sipil 12, no. 1 (July 17, 2019): 1. http://dx.doi.org/10.33795/prokons.v12i1.146.
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Genting is a utility roof materials above the building that serves as a protective weather and channeling rain water that was on it down. Alternative yangb concrete tiles is done more efficiently without the combustion process. Kelud the ash sand fly bergradai to the distance, in other words the farther the distance of the small grain diameter at a given radius. The heat caused by the Volcanic magma, ash makes Kelud Sand has a high water absorption, but will have saturated and rejected, resulting in bledding. By mixing sand times as a species, then an increase hidroulis and mechanical properties of an ideal mix ratio. From the experiment results for the compressive strength of the mixture 2: 2: 1 is stronger ie max 108.00 kg /cm2, a mixture of 3: 2: 1 compression stress value obtained sbesar 64.00 kg /cm2 and the mixture of 4: 2: 1 obtained compressive stress value of 24.00 kg /cm2. As for the bending stress fracture to a mixture of 2: 2: 1 max values obtained at 33.5 kg / cm2and for a mixture of 3: 2: 1 max values obtained at 23.33 kg /cm2 while for mixture 3: 2: 1 obtained value max of 5.33 kg /cm2, and water absorption in the saturated surface dry condition for a mixture of 2: 2: 1 obtained 10.23%, water absorption in the saturated surface dry condition for a mixture of 3: 2: 1 obtained 11.82 %, water absorption on the condition of saturated surface dry to mix 4: 2: 1 obtained 12.81%,. Then for mains water tembur can be seen in the discussion section, but can be inferred to mix 2: 2: 1 is more dense because Crystal showed a copy with a little water and a relatively dry and to a mixture of 4: 2: 1 indicates a copy with softer water crystals and evenly with a small diameter, both assessed at the time of maximum concentration, while for the mixture 3: 2: 1 is more porous at the same time. Keywords: genting concrete, hydraulic properties, volcanic gradient, mixed ideal
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Логанина, В., Valentina Loganina, М. Фролов, and Mihail Frolov. "STUDY OF THE SYNERGETIC EFFECT OF ADDITIVE BASED ON CALCIUM HYDROSILICATES AND HYDROALUMINOSILICATES." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 4, no. 7 (July 21, 2019): 8–13. http://dx.doi.org/10.34031/article_5d35d0b645d6f8.37881085.
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Dry mixes of various functional purposes are widely used in construction works. Modifying additives are introduced into the composition of dry building mixtures to improve various characteristics of finishing compositions and coatings. Foreign companies supply most modifying additives, this significantly increases the cost of production of dry building mixtures. Therefore, the urgent task is to develop domestic modifying additives. The paper proposes the use of modifying additive for the finishing of aerated concrete in calcareous heat-insulating finishing compositions, the mineralogical composition of which is consisted of hydrosilicates and calcium hydroaluminosilicates. The expediency of the adopted two-stage technology for the synthesis of the modifying additive is proved. The synergistic effect of the modifying additive influence based on a mixture of hydrosilicates and calcium hydroaluminosilicates on the structure formation of lime composites is established. It is revealed that the use of modifying additive increases the compressive strength, the water resistance of lime composites and the speed of the set of flexible strength of the lime composition. The modifying additive, the mineralogical composition of which is represented by hydrosilicates and calcium hydroaluminosilicates, is used in the formulation of thermal insulation of dry mixes designed for interior and exterior walls of aerated concrete.
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Akçaözoğlu, Semiha. "The effect of elevated temperature on the lightweight concrete containing waste PET aggregate." International Journal of Business & Technology 6, no. 3 (May 1, 2018): 1–14. http://dx.doi.org/10.33107/ijbte.2018.6.3.20.
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In this study, the effect of waste PET as lightweight aggregate (WPLA) replacement with conventional aggregate on the some physical and mechanical properties and residual compressive strength of concrete was investigated. For this purpose, five different mixtures were prepared (the reference mixture and four WPLA mixtures including 30%, 40%, 50% and 60% waste PET aggregate by volume). The fresh and dry unit weights, compressive strengths, flexural-tensile strengths, water absorption and porosity ratios of the mixtures were measured. In addition the specimens exposed to elevated temperatures at 150, 300 and 450 °C and the residual compressive strengths were measured. Test results indicated that the unit weight, compressive strength and flexural-tensile strength of the specimens decreased as the amount of WPLA increased in concrete. After exposing to elevated temperature, WPLA mixtures retained their structural integrity and compressive strengths at 150 °C and 300 °C. However there was a significant decrease in the residual compressive strength values of WPLA mixtures at 450 °C.
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Ahmad, Shamsad, Ahmed Zubair, and Mohammed Maslehuddin. "Effect of the Key Mixture Parameters on Shrinkage of Reactive Powder Concrete." Scientific World Journal 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/426921.
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Reactive powder concrete (RPC) mixtures are reported to have excellent mechanical and durability characteristics. However, such concrete mixtures having high amount of cementitious materials may have high early shrinkage causing cracking of concrete. In the present work, an attempt has been made to study the simultaneous effects of three key mixture parameters on shrinkage of the RPC mixtures. Considering three different levels of the three key mixture factors, a total of 27 mixtures of RPC were prepared according to 33factorial experiment design. The specimens belonging to all 27 mixtures were monitored for shrinkage at different ages over a total period of 90 days. The test results were plotted to observe the variation of shrinkage with time and to see the effects of the key mixture factors. The experimental data pertaining to 90-day shrinkage were used to conduct analysis of variance to identify significance of each factor and to obtain an empirical equation correlating the shrinkage of RPC with the three key mixture factors. The rate of development of shrinkage at early ages was higher. The water to binder ratio was found to be the most prominent factor followed by cement content with the least effect of silica fume content.
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Sulejmani, Pajtim, Safwat Said, Sven Agardh, and Abubeker Ahmed. "Moisture Sensitivity of Asphalt Mixtures using Cycling Pore Pressure Conditioning." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 2 (January 19, 2019): 294–303. http://dx.doi.org/10.1177/0361198118823496.
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One of the major causes of premature failure in asphalt pavements is moisture damage. Asphalt mixtures designed without considering climate impacts may suffer from durability problems caused by movement of water inside the asphalt mixture. Rolling traffic over wet pavement builds up pore pressure in the mixture, which will consequently accelerate deterioration. The objective of the study was to assess the moisture damage to asphalt concrete mixtures by means of complex modulus testing of dry and moisture-conditioned asphalt specimens with various mixture compositions. The asphalt mixtures were conditioned with the Moisture Induced Sensitivity Tester (MIST), which aims to replicate pore pressure in field conditions. The results showed a decline in stiffness modulus and a reduction in elastic properties after MIST conditioning. In addition, the results indicated that binder content and air void content had a significant influence on the reduction in stiffness. To capture the relationship between air void content, binder content, and the reduction in stiffness, a relationship was developed and validated with measurements on cores extracted in the field.
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Xian, Xiang Ping, Wu Jian Long, Biao Yi Chen, Min Yi Huang, and Yong Fa Fan. "High-Strength Self-Compacting Concrete and its Application in Shenzhen Mangrove Garden." Applied Mechanics and Materials 438-439 (October 2013): 338–41. http://dx.doi.org/10.4028/www.scientific.net/amm.438-439.338.
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Self-compacting concrete (SCC) refers to one kind of high-performance concrete which can fill formwork and condensed reinforced steel by the weight of concrete mixture without vibration. In this investigation, local raw materials from Shenzhen Jinqiang Concrete Co. Ltd were employed. Self-compacting concrete mixtures with targeted 3-day compressive strengths of 60MPa or 80MPa and required flow properties were evaluated. Moreover, the SCC was successfully applied in Shenzhen Mangrove Garden project.
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Laukaitis, A. "INVESTIGATION INTO POROUS CONCRETE FORMATION PECULIARITIES WITH A MIXED BINDER COMPOSITION/DUJŲ BETONO SU MIŠRIA RIŠANČIĄJA MEDŽIAGA FORMAVIMO YPATUMŲ TYRIMAI." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 1, no. 4 (December 31, 1995): 75–81. http://dx.doi.org/10.3846/13921525.1995.10531535.
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Porous concrete is a cheap material produced from local raw materials. That is why, it is important to improve it's properties, especially the product's density. This paper deals with porous concrete made using a mixed binder composition (lime+Portlandcement) formation peculiarities and determination of optimal product formation parameters for 300–350 kg/m3product dependency on the binder mixture composition. A wide density interval (200–500 kg/m3) was investigated to determine the optimal above mentioned porous concrete density parameters. It was determined, that the porous concrete density with a mixed binder composition has a complex dependency from water and dry solids ratio (V/K), mixed binder composition and amount of Al powder. Mathematical equations of porous concrete density on technological parameter were derrived. It was found that the lime contant increase in the lime- Portlandcement binder mixture, lowers Al powder effectiveness, increases the product's density and decreases the technological operation time duration.
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Smittakorn, Watanachai, Pattraporn Manavithayarak, and Patra Sukmoung. "Improvement of shear capacity for precast segmental box girder dry joints by steel fiber and glass fiber." MATEC Web of Conferences 258 (2019): 04006. http://dx.doi.org/10.1051/matecconf/201925804006.
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The use of precast segmental box girders in the bridge construction projects yields many benefits: economy, high quality, rapid construction, and minimal disruption to site. Previously, precast segments are connected together by epoxy joints. Epoxy fills in the gaps and makes strong connection, but it takes time and effort in the construction process. Later, dry joints have been introduced in the process, and hence the construction could be done much faster. However, there exists some drawback in using the dry joints. The contact surface between segments, especially at shear keys, can hardly be made smooth and well-fitted together. Consequently, the transferred shear strength cannot be developed to its full capacity. This study is an attempt to improve the capacity of shear strength of dry joints by adding steel fiber and glass fiber into concrete mixture. Considering specimens with single shear key, experiments have been conducted for shear capacities of 5 specimen types: ordinary concrete, concrete mixed with 1% and 2% steel fiber, and concrete mixed with 1% and 2% glass fiber. Results from experiments have shown that steel fiber helps increase the shear capacity of dry joints while glass fiber somehow degenerates the shear capacity and the compressive strength of concrete.
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Kovalenko, O. V. "Modern cement-based waterproofings for hydraulic structures protection." Міжвідомчий тематичний науковий збірник "Меліорація і водне господарство", no. 1 (June 25, 2020): 175–85. http://dx.doi.org/10.31073/mivg202001-222.
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Hydrotechnical structures of water management and land reclamation complex from the moment of commissioning are subject to aggressive environmental effects: hydrostatic water pressure, alternating freezing and thawing, moistening and drying, corrosive action of salts dissolved in water, dynamic action of ice. The trouble-free operation of structures with long-term aggressive environmental factors is possible only in the case of providing their protection (reinforcement) with effective insulating, anticorrosive, high-strength, wear-resistant and cavitation-resistant composite materials.
Waterproofing coatings, which arrange on the surface of reinforced concrete structures, plays an important role in ensuring operational reliability and durability of hydraulic structures. Having rather low cost of waterproofing coatings as compared to the cost of structures the fate of their responsibility in terms of ensuring the durability and operational reliability of the structures is high enough. Waterproofing coatings serve as a barrier to an aggressive environment and thus protect structures from destruction.
Notwithstanding the importance of waterproofing protection, this issue is not given due attention today. Therefore, filtration of water through the structures of water-reclamation facilities is a common phenomenon. Water filtration through damaged concrete of hydraulic structures causes dissolution and leaching of water with calcium hydroxide (leaching), which further causes the decomposition of other components of the cement stone and leads to the dilution of the concrete structure and to the strengthening of drip filtration. Drip filtration increases over time, then jet filtration develops, which can lead to complete destruction of the structure. Therefore, providing waterproofing protection of structures is an important engineering task in their construction and operation.
One of the determining factors for the effectiveness of waterproofing is the right selection of material. Traditional waterproofing materials on a bituminous basis have insufficient physical-mechanical properties and durability. However, modern technologies of waterproofing protection of concrete and reinforced concrete structures are based on the use of effective composite materials with high physical, mechanical and protective properties. Depending on the type of binder, waterproofing materials can be based on bitumen, bituminous-mineral, bitumen-polymer, coal, polymer compositions, as well as on the basis of cements and polymer cements.
The selection of a waterproofing material should be made taking into account the specifics of the operating environment and the conditions of use. The most common in the construction of gluing roll materials on a bituminous basis can only partially satisfy the need for hydraulic engineering, as for the waterproofing of hydraulic structures. There are high requirements with regard to the aggressiveness of the environment and their low repairsability.
The most promising for use in the technology of arrangement of waterproofing coatings on concrete and reinforced concrete structures of hydraulic engineering facilities of water management and reclamation complex are polymer cement mixtures, binders in which are Portland cement modified with polymer latex dispersion powder (for two-component).
Creation of effective polymer cement waterproofing compositions is based on optimization of the ratio of interpenetrating meshes of polymers and crystal matrix hydrates. Modification of cement systems by polymers allows to increase adhesion and deformation characteristics, fracture resistance and corrosion resistance of polymer cement composites. Depending on the components included in the mixture, waterproofing coatings may be rigid or elastic. Rigid formulations are a water-mixed, dry mixture that includes a vinyl acetate copolymer and designed for waterproofing concrete and reinforced concrete structures with low water filtration. Elastic waterproofing materials are usually two-component. These materials are used for waterproofing structures that are susceptible to deformation, as well as surfaces with a high degree of water filtration and where cracks up to 1 mm are formed. Elastic two-component formulations are dry mixtures with the addition of redispersible polymer powders. They consist of two components: a dry mixture of modified fine cement and aqueous latex polymer, usually acrylic.
The content of polymer latex in the mixture has a significant effect on the rheological properties of polymer-cement mixtures and on the physical and mechanical properties of waterproofing coatings made of them. Thus, the introduction of a redispersible polymer powder Axilat L 8262 in a waterproofing mixture in the amount of up to 10% by weight of cement increases the mobility of the mixture from 3,2 to 8,0 cm, increases the adhesive strength of the coating to concrete from 0,45 to 1,95 MPa, increases its bending strength from 6,9 to 7,9 MPa, reduces its water absorption in 24 hours from 7,02% to 0,35% .
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Kormann, A. C. M., K. F. Portella, P. N. Pereira, and R. P. Santos. "Study of the performance of four repairing material systems for hydraulic structures of concrete dams." Cerâmica 49, no. 309 (March 2003): 48–54. http://dx.doi.org/10.1590/s0366-69132003000100011.
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Four types of repairing materials are studied as function of either a conventional concrete or a reference-concrete (RefC), these are: polymer-modified cement mortar (PMor), steel fiber concrete (SFco), epoxy mortar (EMor) and silica fume mortar (SFmo), to be applied in hydraulic structures surfaces subjected to a high velocity water flow. Besides the mechanical requests and wearing resistance of hydraulic concrete dam structures, especially the spillway surfaces, the high solar radiation, the environmental temperature and wet and dry cycles, contribute significantly to the reduction of their lifespan. RefC and the SFco were developed based on a usual concrete mixture used in slabs of spillways. The average RefC mixture used was 1: 1.61: 2.99: 0.376, with Pozzolan-modified Portland cement consumption of 425 kg/m³. EMor and PMor mixtures followed the information given by the manufacturers and lab experience. Tests on concrete samples were carried out in laboratory simulating normally found environmental situations in order to control the mechanical resistance and the aging imposed conditions, such as solar radiation and humidity. Also, physicochemical characterizing tests were made for all used materials. From the analyzed results, two of them presented a higher performance: the EMor and SFmo. SFco presented good adherence to the RefC and good mechanical performance. However, it also presented apparent metal corrosion in humidity tests, being indicated for use, with caution, as an intermediate layer in underwater repairs. In a general classification, considering all tests, including their field applications, the better performance material systems were EMor- SFmo> SFco> PMor.
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Almeida, Arminda, João Crucho, César Abreu, and Luís Picado-Santos. "An Assessment of Moisture Susceptibility and Ageing Effect on Nanoclay-Modified AC Mixtures Containing Flakes of Plastic Film Collected as Urban Waste." Applied Sciences 9, no. 18 (September 7, 2019): 3738. http://dx.doi.org/10.3390/app9183738.
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In this research, the moisture susceptibility of a nanoclay-modified asphalt concrete (AC) mixture containing plastic film (in flakes) collected as urban waste was evaluated with specimens subjected to the tecnico accelerated ageing (TEAGE) procedure. The TEAGE procedure attempts to simulate—in a laboratory setting—the effect of field ageing by applying watering/drying cycles and ultraviolet radiation. For comparison purposes, three AC mixtures were considered, one for control, without plastic and nanoclay, a mixture with only plastic, and a mixture with both plastic and nanoclay. Furthermore, only half of the specimens were subjected to the ageing procedure. The plastic was added to the mixture using the dry process, and the nanoclay was blended with the bitumen before mixture preparation. The moisture susceptibility was evaluated, using a total of 48 Marshall specimens, by the indirect tensile strength ratio (ITSR). From the results of this study, the nanoclay-modified AC mixture containing plastic film presented slightly higher indirect tensile strength (ITS) values, lower moisture susceptibility, and enhanced ageing resistance. These slight improvements can be justified by the reduced air voids content of the samples and consequently they must be seen as conservative. Nevertheless, the modification of AC mixtures with flakes of plastic and nanoclay can be a viable solution for the recycling of plastic film collected as urban waste, being an eco-friendly alternative to disposal in landfills.
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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.
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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.
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Ali, Siti Nurul Ain, Amirah Mohamad Juri, Kartini Kamaruddin, Mohd Hisbany Mohd Hashim, and Hamidah Mohd Saman. "Evaluation of the Modulus of Elasticity for Dry Press Lightweight EPS Concrete." Key Engineering Materials 853 (July 2020): 165–70. http://dx.doi.org/10.4028/www.scientific.net/kem.853.165.
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Expanded polystyrene (EPS) concrete is a promising material as lightweight features, environment-friendly materials and potentially used in lightweight building construction. However, EPS concrete has substantially affected the transition zone of elastic behavior of the element. This paper aims to evaluate the modulus of elasticity (MOE) from the compression test method for the EPS concrete. The MOE also was predicted through existing models in codes of practice using actual data from compressive strength and density of EPS concrete. To verify the proposal of a new empirical model from EPS concrete, the actual and prediction of MOE were compared. The EPS concrete specimens were based on EPS replacements and design mixtures. From the outcome of the study, it demonstrated significant improvements in strength and in the elasticity modulus were observed in the implementation of the dry press moulding for concrete mixtures.
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Gomaa, Eslam, Simon Sargon, Cedric Kashosi, Ahmed Gheni, and Mohamed A. ElGawady. "Mechanical Properties of High Early Strength Class C Fly Ash-Based Alkali Activated Concrete." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 5 (May 2020): 430–43. http://dx.doi.org/10.1177/0361198120915892.
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This paper presents the mechanical properties of alkali activated concrete (AAC) cured at 70°C for 24 h. The AAC mixtures were synthesized using five class C fly ashes (FAs) having different chemical and physical properties. Sodium hydroxide (SS) and sodium silicate (SH) were used as the alkali activators in this study. A conventional concrete (CC) mixture, having a compressive strength of 34.5 MPa, was synthesized using ordinary Portland cement (OPC) mixture for comparison purposes. The slump, as well as the compressive, tensile splitting, and flexural strengths were investigated at different concrete ages up to 28 days. The results revealed that with increasing the calcium content in an FA used to synthesized AAC mixture, the slump value and the mechanical properties decreased. All AAC mixtures reached approximately 92% of their 28-day compressive strength after 1 day compared with only 29% in the case of CC. Therefore, AAC can be used in applications where rapid strength gain is required, such as urgent repair, precast industry, and so forth. The measured data was also used to develop a set of equations to accurately predict the splitting tensile and flexural strengths.
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Halim, Samuel Dwima, Edbert Rainer, Chris Ryantonius, Bagas Panandito, Doni Wardoyo, Mhd Reza Fahlevy, and Ivan Sandi Darma. "The use of hazardous sludge solidification and green-lipped mussel shells in cementitious material: a case study of ngcc power plant of priok." MATEC Web of Conferences 147 (2018): 01008. http://dx.doi.org/10.1051/matecconf/201814701008.
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This paper aims to introduce the utilization of hazardous sludge with green-lipped mussel shells as concrete mixture components. The hazardous sludge is a side product of wastewater treatment plant operated in NGCC Priok, while green-lipped mussel shells are side product of community activity in Kalibaru, North Jakarta, Indonesia. Utilization is dedicated to preserve the environment, reducing both hazardous sludge generations from wastewater treatment plant and potential waste from social activities in the coastal area. Three different groups of concretes were prepared. The first group contains normal concretes with W/C ratio of 0.5. Subsequently, the second group contains concretes with dry sludge and mussel as a replacement of fine aggregate at different contents, 5% (C1), 10% (C2), and 15% (C3), with W/C ratio of 0.5. Finally, the last group contains concretes with dry sludge as cement replacement and the green-lipped mussel as fine aggregate replacement at different contents of 5% (C4), 10% (C5), and 15% (C6). The results show that dry sludge and green-lipped mussel provide better results when used as a substitute for fine aggregate rather than as cement replacement. In addition, the rate of strength development of concretes containing waste additions are slow compared to normal concretes.
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Alqamish, Habib H., and Adil K. Al-Tamimi. "Development and Evaluation of Nano-Silica Sustainable Concrete." Applied Sciences 11, no. 7 (March 29, 2021): 3041. http://dx.doi.org/10.3390/app11073041.
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In the last decade, nanomaterials made a major breakthrough in the concrete industry by providing the concrete with unique properties. Earlier studies have shown improvement in the early strength of concrete that can accelerate the construction process. In this study, 1% and 2% of nano-silica were added to concrete mixtures that contain 30% and 70% ground granulated blast-furnace slag (GGBS). Adding 1% of nano-silica to the 30% GGBS mixture showed an increase in the compressive strength by 13.5%, 7.8%, 8.1%, and 2.2% at one day, three days, seven days, and twenty-eight days, respectively. The 2% of nano-silica increased the 30% GGBS mixture’s compressive strength less effectively by 4.3%, 7.6%, and 4.9% at three days, seven days, and 28 days, respectively, when compared to the 1%. On the other hand, adding 1% and 2% of nano-silica reduced the 70% GGBS mixtures’ compressive strength. Moreover, nano-silica reduced the deformability of the mixtures significantly, which caused the increase in the Young’s modulus. The flexural strength of the 30% GGBS mixtures had similar behavior as the 28-day compressive strength. On the other hand, the flexural strength of the 70% GGBS mixtures increased as the nano-silica increased. Nano-silica addition improved the microstructure and the interface structure of the mixtures due to its high pozzolanic activity and the nano-filler effect, which is confirmed by RCPT results and SEM images.
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Kubissa, Wojciech, Barbara Pacewska, and Iwona Wilińska. "Comparative Investigations of some Properties Related to Durability of Cement Concretes Containing Different Fly Ashes." Advanced Materials Research 1054 (October 2014): 154–61. http://dx.doi.org/10.4028/www.scientific.net/amr.1054.154.
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The results of research of mechanical properties and selected other characteristics influencing durability of cement concretes containing cement substitutes were presented. Cement concretes performed with conventional fly ash, fluidised fly ash and their mixture were investigated. The obtained results were compared with findings registered for two types of concrete performed without cement replacements and with cement concrete containing silica fume. The results have shown that cement concrete with predetermined 28-day compressive strength of about 50 MPa and good workability may be obtained using different cement replacements. Generally, these cement concretes exhibited also favorable properties related to concrete durability, i.e. low permeability and sorptivity, and significant reduction of chloride migration coefficient. Favourable results were obtained for cement concrete containing mix of conventional and fluidised fly ashes: good workability, compressive strength after 28th day exceeding 50 MPa, low permeability of water, and low sorptivity, as well as low coefficient of chloride migration. These features were similar as for cement concrete containing silica fume.
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Barabash, I. V., A. I. Vorokhaiev, and L. M. Ksonshkevуch. "HYDROPHOBIZATION OF BASALT FIBER AND ITS INFLUENCE ON THE MECHANICAL CHARACTERISTICS OF SAND CONCRETE." Bulletin of Odessa State Academy of Civil Engineering and Architecture, no. 81 (December 7, 2020): 114–20. http://dx.doi.org/10.31650/2415-377x-2020-81-114-120.
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Abstract. The materials of the proposed article are devoted to the study of mechanical properties of sand concrete with the addition of hydrophobized basalt fiber and polycarboxylate superplasticizer Relaxol-Super PC. Adding hydrophobic properties to the basalt fiber causes a decrease of water consumption of fine-grained concrete mixture, which leads to improved mechanical properties of concrete. The aim of the work was to increase the mechanical characteristics of sand concrete by introducing hydrophobized basalt fiber into its composition. The objective of the research is to study the effect of hydrophobized basalt fiber on the mechanical characteristics of sand concrete. The polycarboxylate superplasticizer Relaxol-Super PC (Budindustriya, Zaporozhye) was used to increase the mobility of the concrete mixture. Basalt fiber Bauson-basalt 12 mm long and 18 ± 2μm in diameter was used as a fibrous filler. Sand concrete mixture was prepared in a laboratory forced-action mixer. Dosing of Portland cement, quartz sand and basalt fiber was carried out by weight, water and water-reducing additive ‒ by volume, taking into account the density of the additive. The fiber was introduced into a dry cement-sand mixture. After mixing for 120 ... 150 seconds, water with a dosed amount of additive was introduced into the mixture. The hardening of samples concrete took place under normal conditions in a chamber with a temperature of 20 ± 20C and a relative humidity of at least 95%. The compressive strength of concrete was determined by testing the halves of the samples – beams 4×4×16 cm in size at 28 days of age. The abrasion of the investigated concrete was determined by testing cube specimens with an edge of 7.07 cm on an LKI-3 device in accordance with the procedure set forth in DSTU B.V.2.7-212: 2009 “Building materials. Concrete. Methods for determining abrasion “. The impact resistance of concrete was determined from the results of testing cubic specimens with an edge of 7.07 cm on a vertical dynamic laboratory test machine. Especially effective is manifested positive role hydrophobization basalt fiber in combination with the water-reducing additive Relaxol-Super PC. The introduction of hydrophobic fiber (2 kg/m3) and Relaxol – Super PC (1.2% by weight of cement) into the sand concrete mix provides an increase in the strength of sand concrete by 45 ... 48%, impact resistance by 45 ... 50%. The abrasion of concrete is reduced by 36 ... 48% compared to the control.
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Mu, Song, Ye Wu, Qian Jiang, and Liang Shi. "Study on Transient Air Permeability of Concrete under Different Curing Conditions." Key Engineering Materials 629-630 (October 2014): 223–28. http://dx.doi.org/10.4028/www.scientific.net/kem.629-630.223.
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Quality of concrete cover is a key factor for concrete durability. In fact, the quality of concrete cover has close relationship with mixture design and curing condition. Present study adopted transient test of air permeability to study on affecting factors of air permeability of concrete. Results dedicated that curing condition was the most important factor to affect transient air permeability of concrete. Adequate curing is required to decrease effectively the air permeability, and low ratio of W/B is helpful to reduce air permeability. Air permeability of concrete samples, added with fly ash or slag powder, was more sensitive to dry curing than standard curing. Besides, CaO based expansive agent effectively decreased coefficient of air permeability at the adequate curing condition
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Alamayehu, Worku, Hedvig Fébel, Szilvia Orosz, Tamȧs Tóth, György Bȧzȧr, Lȧszlo Kacsala, and Róbert Tóthi. "Nutrient content and fermentation characteristics of ensiled Italian ryegrass and winter cereal mixtures for dairy cows." Krmiva 61, no. 1 (May 25, 2020): 3–10. http://dx.doi.org/10.33128/k.61.1.6.
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The interest in new alternative forages in Europe has increased in recent years. The nutritional composition and fermentation characteristics during different stages of ensiling were studied with Italian ryegrass (Lolium multiflorum Lam.) and winter cereal mixtures. The trial was carried out on a large-scale farm Galgamenti Agricultural Limited Company, Tura, Hungary. Two different forage mixes were studied: Mixture A (three types of Italian ryegrass 40% + two types of triticale 20%+ two types of oats 20%+ wheat 15%+ barley 5%) and Mixture B (three types of Italian ryegrass 55% + two types of winter oats 45%). Experimental field was 30.600 m 2 by the treatments, respectively. The two different forage mixes were sown on 11th September 2017 (Mixture A: 75 kg seed/ha; Mixture B: 75 kg seed/ha) with depth of 2-5 cm. Plant protection treatment was not applied during the growing season. Cutting was carried out in heading stage of triticale by hand at 10 cm stubble height. The fresh Mixture A (dry matter 189 g/kg; crude protein: 161 g/kg DM; NDF: 485 g/kg DM) and the fresh Mixture B (dry matter 195 g/kg; crude protein: 159 g/kg DM; NDF: 519 g/kg DM) were wilted to 28-32% DM (24h) without any movement on the windrow. The wilted forage was picked up by hand and chopped by a forage harvester (John Deere 7300) on concrete surface with theoretical chop length of 9 mm (weight: 800 kg). Wilted and chopped material of 510 g were packed by hand into a glass jars (0.00072 m3 volume, n=5, total no. of minisilos = 15). Five laboratory silos per mixtures were opened on 7, 14 and 90 days after ensiling. Dry matter (DM), crude protein (CP), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), ether extract (EE), ash, and total sugar of all treatments were determined. Additionally, pH and the concentration of ammonia-N, volatile fatty acids were measured in the ensiled mixtures. At the end of 90 days of ensiling in both mixture silages, there were significant differences (p<0.05) in all nutrient contents except for ADF in Mixture A and CP, ash and CF in Mixture B which was not affected by fermentation duration. Ensiling caused a significant decrease in pH (p<0.05), due to the production of lactic acid and succeeded to achieve lactic acid type fermentation. Values for ammonia-N, ethanol and acetic acid, butyric acid were all low. These results indicated that the fermentation quality of Italian ryegrass and winter cereal silages underwent rapid fermentation and were well-preserved.
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Niu, Lian Jie, Jun Hong Li, and Ning Cui. "The Principal Component Analysis about Optimal Ratio for High Performance Pavement Concrete." Applied Mechanics and Materials 446-447 (November 2013): 1417–20. http://dx.doi.org/10.4028/www.scientific.net/amm.446-447.1417.
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The high performance cement concrete mixture design for pavement was studied through a series of laboratory experiments based on an actual project program. We analyzed the data by principal component analysis and tested the concrete performance of strength, shrink and freeze-resistance. The results of a series of experiments indicated that the dry-shrink rate was reduced obviously by using expanding agent. The flexural elastic modulus increased as the flexural strength increasing. Adding air-entraining agent could improve the air content of the concrete, and as a result, the flexural elastic modulus was reduced and freeze-resistance performance was enhanced greatly.
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Han, Hyung Sub, Jong Kyu Kim, and Yong Wook Jung. "Development and Performance Assessment of the High-Performance Shrinkage Reducing Agent for Concrete." Advances in Materials Science and Engineering 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/9318086.
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To develop a high-performance shrinkage reducing agent, this study investigated several shrinkage reducing materials and supplements for those materials. Fluidity and air content were satisfactory for the various shrinkage reducing materials. The decrease in viscosity was the lowest for glycol-based materials. The decrease in drying shrinkage was most prominent for mixtures containing glycol-based materials. In particular, mixtures containing G2 achieved a 40% decrease in the amount of drying shrinkage. Most shrinkage reducing materials had weaker level of compressive strength than that of the plain mixture. When 3% triethanolamine was used for early strength improvement, the strength was enhanced by 158% compared to that of the plain mixture on day 1; enhancement values were 135% on day 7 and 113% on day 28. To assess the performance of the developed high-performance shrinkage reducing agent and to determine the optimal amount, 2.0% shrinkage reducing agent was set as 40% of the value of the plain mixture. While the effect was more prominent at higher amounts, to prevent deterioration of the compressive strength and the other physical properties, the recommended amount is less than 2.0%.
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Amri, Dian, and Irwan Irwan. "Pengaruh Penambahan Pecahan Kulit Kemiri Sebagai Pengganti Sebagian Agregat Kasar Pada Beton Terhadap Massa Dan Kuat Tekan Beton." JOURNAL OF CIVIL ENGINEERING, BUILDING AND TRANSPORTATION 3, no. 2 (September 10, 2019): 88. http://dx.doi.org/10.31289/jcebt.v3i2.2778.
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Concrete is a material that is widely used and become a major element in the building. The advantages of concrete, among others, have a strong high pressure than the tensile strength, easily formed, does not require special care, the material is easy to obtain from the surrounding, and more durable than other building materials. The more concrete is used as the constituent material of the concrete, hence encouraging research to develop the material as well as the way of making concrete. Hazelnut shell is one type of particle that is very light weight in a dry and quite hard. Where the hazelnut shell is it self known as a lot of waste accumulated and tend to become garbage because its utilization is still small or relatively small, so it needs to be handled seriously. In addition, today hazelnut shell is only used for a small need only. The purpose of this research is to find out the compressive strength of concrete and to utilize the waste of hazelnut shell as 10%, 20% and 30% concrete additives with the planned K225 concrete quality, with 28 days concrete plan, The addition of hazelnut shell to the concrete mixture resulted decrease in compressive strength of normal concrete in each variation of the percentage. This is because the mixture of hazelnut shell is not strong enough to be a substitute for coarse aggregates, resulting in a decrease in the compressive strength of the concrete
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Belyakov, V. A., and L. A. Bannikova. "Study and Analysis of Aluminate Dry Construction Mixtures Properties." Solid State Phenomena 265 (September 2017): 398–402. http://dx.doi.org/10.4028/www.scientific.net/ssp.265.398.
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The article presents the results of studies of a series of dry construction mixtures, being the most popular on the local market for repair of concrete and reinforced concrete structures, in order to improve their performance by modifying composition of their components. The studies included X-ray phase analysis and the research of technological and operational properties of the mixtures. The work proved a possibility to replace the imported aluminous cement in dry repair mixtures with a Russian equivalent bringing along a simultaneous product cost reduction. The studies selected a required aluminous cement-to-Portland cement proportion in repair mortar to ensure optimal setting time and strength characteristics consistent with the initial recipes in case of replacement.