The main purpose of this research is to study the properties of re-use different types of construction materials such as PVC （polyvinylchloride） scraps, clay brick and recycled concrete as a partial replacement of c...The main purpose of this research is to study the properties of re-use different types of construction materials such as PVC （polyvinylchloride） scraps, clay brick and recycled concrete as a partial replacement of coarse aggregate. Different proportions （1%, 3%, 5% and 7%） by weight were used for PVC. scrap, （10%, 20%, 30%, and 40%） by weight were used for recycled concrete and （5%, 10%, 15%, and 20%） by weight were used for clay brick. Mechanical tests such as compressive and tensile strength tests and physical tests such as ultrasonic pulse velocity, bulk density, porosity, specific gravity and water absorption tests were done to the samples after curing in normal water for 28 days. Test results showed slightly degradation in mechanical and physical engineering properties of concrete specimens that used partial replacement of recycled concrete coarse aggregate, degradation increased with increasing of replacement but test results still closely to reference samples. Use of polyvinyl chloride in proportions not more than 5% as a partial replacement of coarse aggregates given acceptable results in comparison with reference samples but all test results degraded at 7% replacements. Test results of partial replacement of crushed brick coarse aggregates unacceptable and the range of degradation are wide because of increased （water： cement） ratio to improve the concrete workability.展开更多
Crushed over-burnt clay bricks(COBCBs)are a promising alternative to the natural gravel aggregate in lightweight concrete(LWC)production because of their high strength-to-weight ratio.Besides,COBCBs are considered a g...Crushed over-burnt clay bricks(COBCBs)are a promising alternative to the natural gravel aggregate in lightweight concrete(LWC)production because of their high strength-to-weight ratio.Besides,COBCBs are considered a green aggregate as they solve the problem of solid waste disposal.In this paper,a total of fifteen reinforced concrete(RC)beams were constructed and tested up to failure.The experimental beams were classified into five groups.The con-trol beams were cast with normal weight concrete(NWC),while the remaining four groups of beams were prepared from LWC.The test parameters were the concrete type,reinforcement ratio and silica fume(SF)content.The behavior of beams was evaluated in terms of the crack pattern,failure mode,ultimate deflection,and ductility.The experimen-tal results suggested that the weight and strength of the concrete prepared satisfied the requirements of LWC.In addition,the increase in the reinforcement ratio and SF content improved the behavior of the beams.It is noteworthy that the SF addition caused measurable enhancements to the majority of the performance characteristics of LWC beams.Thus,COBCBs were successfully used as coarse aggregates in the production of high-quality LWC.Both ACI 318-19 and CSA-A23.3-19 made acceptable predictions of the cracking moment,ultimate capacity and mid-span deflection.展开更多
文摘The main purpose of this research is to study the properties of re-use different types of construction materials such as PVC （polyvinylchloride） scraps, clay brick and recycled concrete as a partial replacement of coarse aggregate. Different proportions （1%, 3%, 5% and 7%） by weight were used for PVC. scrap, （10%, 20%, 30%, and 40%） by weight were used for recycled concrete and （5%, 10%, 15%, and 20%） by weight were used for clay brick. Mechanical tests such as compressive and tensile strength tests and physical tests such as ultrasonic pulse velocity, bulk density, porosity, specific gravity and water absorption tests were done to the samples after curing in normal water for 28 days. Test results showed slightly degradation in mechanical and physical engineering properties of concrete specimens that used partial replacement of recycled concrete coarse aggregate, degradation increased with increasing of replacement but test results still closely to reference samples. Use of polyvinyl chloride in proportions not more than 5% as a partial replacement of coarse aggregates given acceptable results in comparison with reference samples but all test results degraded at 7% replacements. Test results of partial replacement of crushed brick coarse aggregates unacceptable and the range of degradation are wide because of increased （water： cement） ratio to improve the concrete workability.
文摘Crushed over-burnt clay bricks(COBCBs)are a promising alternative to the natural gravel aggregate in lightweight concrete(LWC)production because of their high strength-to-weight ratio.Besides,COBCBs are considered a green aggregate as they solve the problem of solid waste disposal.In this paper,a total of fifteen reinforced concrete(RC)beams were constructed and tested up to failure.The experimental beams were classified into five groups.The con-trol beams were cast with normal weight concrete(NWC),while the remaining four groups of beams were prepared from LWC.The test parameters were the concrete type,reinforcement ratio and silica fume(SF)content.The behavior of beams was evaluated in terms of the crack pattern,failure mode,ultimate deflection,and ductility.The experimen-tal results suggested that the weight and strength of the concrete prepared satisfied the requirements of LWC.In addition,the increase in the reinforcement ratio and SF content improved the behavior of the beams.It is noteworthy that the SF addition caused measurable enhancements to the majority of the performance characteristics of LWC beams.Thus,COBCBs were successfully used as coarse aggregates in the production of high-quality LWC.Both ACI 318-19 and CSA-A23.3-19 made acceptable predictions of the cracking moment,ultimate capacity and mid-span deflection.
