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Sreekanta Das - One of the best experts on this subject based on the ideXlab platform.
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performance of engineered cementitious composites incorporating crumb rubber as aggregate
Construction and Building Materials, 2021Co-Authors: Adeyemi Adesina, Sreekanta DasAbstract:Abstract Engineered cementitious composites (ECC) are a special type of fiber reinforced cementitious composites that are reinforced with Polyvinyl alcohol fibers. ECC exhibits outstanding deformable and durability properties. However, the limited availability and high cost of silica sand required for the production of ECC have limited its widespread applications. Hence, it is imminent to find materials that can be used as alternatives to partially or totally replace the silica sand in ECC. This paper presents the results from a feasibility study on the use of crumb rubber which is a recycled material as aggregates in ECC mixtures. In this study, crumb rubber was incorporated to replace the silica sand up to 100% and the influence on the performance evaluated. The study showed that the incorporation of crumb rubber causes a reduction in the strength of the ECC, though these ECC qualify to be used in the structural application. Also, the ductility and the durability of ECC incorporating crumb rubber was improved with the incorporation of crumb rubber. The mid-Span Deflection and tensile strain of ECC incorporating only crumb rubber as aggregate were found to be 96.8% and 110.2%, respectively higher than the ECC made with only silica sand as aggregate. Also, the incorporation of crumb rubber as aggregate into the mixtures resulted in a reduction in the permeability properties of the composites. The porosity, water absorption and chloride penetration of ECC were reduced by 33%, 36% and 12%, respectively when crumb rubber was used as a 100% replacement of silica sand.
Saber Fallahvalukolaee - One of the best experts on this subject based on the ideXlab platform.
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experimental and analytical investigation on structural behavior of two layer fiber reinforced concrete beams reinforced with steel and gfrp rebars
Construction and Building Materials, 2021Co-Authors: Mahdi Nematzadeh, Saber FallahvalukolaeeAbstract:Abstract The combination of plain concrete and fiber-reinforced concrete in beams in the form of two-layer composite members can be an efficient solution to improve the flexural behavior, reach the optimum distribution of steel fibers, and reduce the cost of these structural elements. On the other hand, the glass fiber reinforced polymer (GFRP) rebar can serve as a proper alternative for the steel rebar in reinforced concrete beams considering its superior strength to weight ratio compared with the steel rebar. The objective of this research was to evaluate the structural performance of two-layer fiber-reinforced concrete beams with glass fiber-reinforced polymer (GFRP) and steel rebars under quasi-static loads. For this purpose, three groups of concrete beams reinforced with GFRP rebars and four groups of concrete beams reinforced with steel rebars were fabricated with one- and two-layer sections containing different volume fractions of steel fibers (Vf = 0, 0.75, and 1.5%), without using shear reinforcement. The longitudinal reinforcement ratios were 0.37 and 0.73% for GFRP and 1.05 and 2.1% for steel rebars, and the concrete compressive strengths were 33 and 64 MPa. The fabricated beams were then tested under three-point bending. The results of the layered concrete beams showed that adding fibers to the compression zone of the section led to a higher ductility in both GFRP rebar- and steel rebar-reinforced beams, while adding fibers to the tensile zone led to a higher ultimate flexural strength. Furthermore, an increase in the ratio of GFRP and steel reinforcement together with a greater concrete compressive strength in the layered beams enhanced their flexural performance in terms of load-carrying capacity, flexural stiffness, and ductility; however, replacing steel rebars with GFRP ones led to a decrease in these parameters. Finally, the flexural response of the layered concrete beams reinforced with GFRP and steel rebars was predicted via sectional analysis and using empirical equations developed for the mechanical properties of the constituent materials. The analytical results indicated a good agreement between the proposed model and the experimental results, to the extent that the model was able to properly predict the flexural behavior of the layered concrete beams in terms of the ultimate load-carrying capacity and mid-Span Deflection.
Haibin Geng - One of the best experts on this subject based on the ideXlab platform.
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bending performance of steel fiber reinforced concrete beams based on composite recycled aggregate and matched with 500 mpa rebars
Materials, 2020Co-Authors: Songwei Pei, Kunpeng Fan, Haibin GengAbstract:To promote the engineering application of recycled aggregate for concrete production with good adaptability and economic efficiency, this paper performed a campaign to investigate the flexural performance of steel fiber reinforced composite-recycled aggregate concrete (SFR-CRAC) beams matched with 500 MPa longitudinal rebars. The composite-recycled aggregate has features of the full use recycled fine aggregate and small particle recycled coarse aggregate, and the continuous grading of coarse aggregate ensured by admixing the large particle natural aggregate about 35% to 45% in mass of total coarse aggregate. The properties of SFR-CRAC have been comprehensively improved by using steel fibers. With a varying volume fraction of steel fiber from 0% to 2.0%, 10 beam specimens were produced. The flexural behaviors of the beams during the complete loading procedure were experimentally studied under a four-point bending test. Of which the concrete strain at mid-Span section, the appearance of cracks, the crack distribution and crack width, the mid-Span Deflection, the tensile strain of longitudinal rebars, and the failure patterns of the beams were measured in detail. Results indicated that the assumption of plane cross-section held true approximately, the 500 MPa longitudinal rebars worked at a high stress level within the limit width of cracks on reinforced SFR-CRAC beams at the normal serviceability, and the typical failure occurred with the yield of 500 MPa longitudinal rebars followed by the crushed SFR-CRAC in compression. The cracking resistance, the flexural capacity, and the flexural ductility of the beams increased with the volume fraction of steel fiber, while the crack width and mid-Span Deflection obviously decreased. Finally, by linking to those for conventional reinforced concrete beams, formulas are suggested for predicting the cracking moment, crack width, and flexural stiffness at normal serviceability, and the ultimate moment at bearing capacity of reinforced SFR-CRAC beams.
Adeyemi Adesina - One of the best experts on this subject based on the ideXlab platform.
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performance of engineered cementitious composites incorporating crumb rubber as aggregate
Construction and Building Materials, 2021Co-Authors: Adeyemi Adesina, Sreekanta DasAbstract:Abstract Engineered cementitious composites (ECC) are a special type of fiber reinforced cementitious composites that are reinforced with Polyvinyl alcohol fibers. ECC exhibits outstanding deformable and durability properties. However, the limited availability and high cost of silica sand required for the production of ECC have limited its widespread applications. Hence, it is imminent to find materials that can be used as alternatives to partially or totally replace the silica sand in ECC. This paper presents the results from a feasibility study on the use of crumb rubber which is a recycled material as aggregates in ECC mixtures. In this study, crumb rubber was incorporated to replace the silica sand up to 100% and the influence on the performance evaluated. The study showed that the incorporation of crumb rubber causes a reduction in the strength of the ECC, though these ECC qualify to be used in the structural application. Also, the ductility and the durability of ECC incorporating crumb rubber was improved with the incorporation of crumb rubber. The mid-Span Deflection and tensile strain of ECC incorporating only crumb rubber as aggregate were found to be 96.8% and 110.2%, respectively higher than the ECC made with only silica sand as aggregate. Also, the incorporation of crumb rubber as aggregate into the mixtures resulted in a reduction in the permeability properties of the composites. The porosity, water absorption and chloride penetration of ECC were reduced by 33%, 36% and 12%, respectively when crumb rubber was used as a 100% replacement of silica sand.
Ali S Shanour - One of the best experts on this subject based on the ideXlab platform.
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analytical and experimental flexural behavior of concrete beams reinforced with glass fiber reinforced polymers bars
Construction and Building Materials, 2015Co-Authors: Maher Adam, Mohamed Said, Ahmed A Mahmoud, Ali S ShanourAbstract:This paper presents an experimental, numerical and analytical study of the flexural behavior of concrete beams reinforced with locally produced glass fiber reinforced polymers (GFRP) bars. Glass fiber reinforced polymers (GFRP) reinforcement bars has a lower stiffness than steel reinforcement, which should be accounted for the ultimate and serviceability conditions, including the impact on member Deflection and crack widths. The bars are locally produced by double parts die mold using local resources raw materials. A total of ten beams, measuring 120 mm wide � 300 mm deep � 2800 mm long, were cast and tested up to failure under four-point bending. The main parameters were reinforcement material type (GFRP and steel), concrete compressive strength and reinforcement ratio (lb, 1.7 lb and 2.7 lb; where lb is the reinforcement ratio at balanced condition). The mid-Span Deflection, crack width and GFRP reinforcement strains of the tested beams were recorded and compared. The test results revealed that the crack widths and mid-Span Deflection were significantly decreased by increasing the reinforcement ratio. The ultimate load increased by 47% and 97% as the reinforcement ratio increased from lb to 2.7 lb. Specimens reinforced by 2.7 lb can produce some amount of ductility provided by the concrete. The recorded strain of GFRP reinforcement reached to 90% of the ultimate strains. A non-linear finite element analysis (NLFEA) was constructed to simulate the flexural behavior of tested beams, in terms of crack pattern and load Deflection behavior. It can be considered a good agreement between the experimental and numerical results was achieved. Modifications to ACI 440.1R-06 equation for estimating the effective moment of inertia (Ie) of FRP-reinforced concrete beams, using regression analysis of experimental results, is proposed by introducing empirical factors that effectively decrease the Ie at high load level. The proposed equation is compared with different code provisions and previous models for predicting the Deflection. It can proved that the proposed factors gives good estimation for the effective moment of inertia (Ie) works well for FRP-reinforced concrete beams at high load level.