The present work investigates copper slag as a substitute for river sand in high-strength concrete.The concrete mixtures were manufactured with 10%,30%,50%,70%,and 100%of copper slag to evaluate the mechanical and dur...The present work investigates copper slag as a substitute for river sand in high-strength concrete.The concrete mixtures were manufactured with 10%,30%,50%,70%,and 100%of copper slag to evaluate the mechanical and durability properties.The experimental results indicate that replacing copper slag above 50%affects the performance characteristics of the concrete due to its high angularity and lower water absorption characteristics.The strength of concrete with 50%copper slag is improved by 5.6%,whereas the strength of concrete with 100%copper slag is reduced by 2.75%at 28 days.However,increased curing to 90days improves the strength of the former by 7.16%and reduces the latter by only 0.23%.The water absorption,porosity,and rapid chloride penetration of the concrete mixtures with 100%copper slag are increased by 10.44%,13.20%,and 19.56%compared to control concrete.Micro-structural investigations through SEM infer higher replacement of copper results in higher void formation due to its reduced water absorption.展开更多
Excessive construction activities generate huge quantities of waste that are disposed of in nearby sites,leading to environmental degradation.Recycling the concrete fractions of construction wastes for their utilizati...Excessive construction activities generate huge quantities of waste that are disposed of in nearby sites,leading to environmental degradation.Recycling the concrete fractions of construction wastes for their utilization as aggregates has been predominant among industrialists and researchers in recent years.However,the smearance of cement mortar on the recycled aggregates affects the concrete properties.Fewer treatments were developed to remove the weak cement mortar or seal the micro-pores on the adhered cement mortar of recycled aggregates.This paper investigates the comparative efficiency of acid and carbonation treatment on recycled coarse aggregate(RCA)properties and its behaviour on recycled aggregate concrete(RAC).The RCA was treated with HCl acid at 0.1 mol/L,0.5 mol/L,and 0.8 mol/L and CO_(2) at 0.1 bar,0.2 bar,and 0.4 bar and tested for their physical properties,and the concrete mixtures with treated recycled aggregates were tested for fresh and hardened properties.It could be observed that the properties of RAC were affected owing to the smearance of weak mortar,whereas for the concrete with carbonated(RACc)and chemically treated aggregates(RACa),the concrete properties tended to improve.The strength of RAC was 28.59%less than that of normal aggregate concrete(NAC),whereas the strength of RACc and RACa was enhanced by 16.44%and 9.7%compared to that of RAC at 28 days.The water absorption of RAC was 47.51%more than that of NAC,whereas the water absorption of RACa and RACc was 28.67%and 33.75%lesser than RAC.Pre-soaking the RCA with acids removes the adhered mortar due to its acidic activity.In contrast,in carbonation,the CO_(2) reacts with the Ca(OH)_(2) on the cement mortar to form CaCO_(3),filling the micro-cracks in the cement mortar on the RCA.展开更多
基金Part by a Grant from Sona College of TechnologySalem。
文摘The present work investigates copper slag as a substitute for river sand in high-strength concrete.The concrete mixtures were manufactured with 10%,30%,50%,70%,and 100%of copper slag to evaluate the mechanical and durability properties.The experimental results indicate that replacing copper slag above 50%affects the performance characteristics of the concrete due to its high angularity and lower water absorption characteristics.The strength of concrete with 50%copper slag is improved by 5.6%,whereas the strength of concrete with 100%copper slag is reduced by 2.75%at 28 days.However,increased curing to 90days improves the strength of the former by 7.16%and reduces the latter by only 0.23%.The water absorption,porosity,and rapid chloride penetration of the concrete mixtures with 100%copper slag are increased by 10.44%,13.20%,and 19.56%compared to control concrete.Micro-structural investigations through SEM infer higher replacement of copper results in higher void formation due to its reduced water absorption.
文摘Excessive construction activities generate huge quantities of waste that are disposed of in nearby sites,leading to environmental degradation.Recycling the concrete fractions of construction wastes for their utilization as aggregates has been predominant among industrialists and researchers in recent years.However,the smearance of cement mortar on the recycled aggregates affects the concrete properties.Fewer treatments were developed to remove the weak cement mortar or seal the micro-pores on the adhered cement mortar of recycled aggregates.This paper investigates the comparative efficiency of acid and carbonation treatment on recycled coarse aggregate(RCA)properties and its behaviour on recycled aggregate concrete(RAC).The RCA was treated with HCl acid at 0.1 mol/L,0.5 mol/L,and 0.8 mol/L and CO_(2) at 0.1 bar,0.2 bar,and 0.4 bar and tested for their physical properties,and the concrete mixtures with treated recycled aggregates were tested for fresh and hardened properties.It could be observed that the properties of RAC were affected owing to the smearance of weak mortar,whereas for the concrete with carbonated(RACc)and chemically treated aggregates(RACa),the concrete properties tended to improve.The strength of RAC was 28.59%less than that of normal aggregate concrete(NAC),whereas the strength of RACc and RACa was enhanced by 16.44%and 9.7%compared to that of RAC at 28 days.The water absorption of RAC was 47.51%more than that of NAC,whereas the water absorption of RACa and RACc was 28.67%and 33.75%lesser than RAC.Pre-soaking the RCA with acids removes the adhered mortar due to its acidic activity.In contrast,in carbonation,the CO_(2) reacts with the Ca(OH)_(2) on the cement mortar to form CaCO_(3),filling the micro-cracks in the cement mortar on the RCA.
