Axial Compressive Behavior Of CFRP-Confined Recycled Glass Aggregate Cylinders

In recent years,there is an increasing interest worldwide in reusing solid waste with the growing concern in sustainable development.Reusing glass waste,one of forms of solid waste,as recycled aggregates in concrete,can both save the land of landfill and raw materials used in concrete(thus reduce the comsuptiom of resource and engergy),and thus has environmental/economical merit and application value.The glass,however,contains about 70% of amorphous silica,the volume of the gelled hydrate formed by the alkali-silica reaction(ASR)is much larger than the amount of silica consumed.The formation and growth of the gel will cause internal stress in the concrete,which is enough to crack the aggregate particles and cause macroscopic visible micro cracks.The network has an adverse effect on the strength and durability of concrete,which brings damage to the strength and durability of concrete.Fiber Reinforced Polymer(FRP)has been widely used in the strengthening concrete structure reinforcement at home and abroad due to its advantages o f light weight,high strength,excellent corrosion and fatigue resistance.Due to the advantages of FRP-confined concrete,such as improving strength and deformability,protecting core concrete against harsh environmental erosion,FRP-confined recycled aggregate concrete(RAC)has attracted wide attention in the research community in recent years,however,the performance of FRP-confined recycled glass aggregate concrete(RGAC)has not been studied so far.In view of the above research background,this subject has carried out the CFRP(Carbon Fiber Reinforced Polymer)constrained recycled glass aggregate concrete(RGAC)cylindrical axis pressure performance test,the test a total of 126 test pieces,including 56 unconfined RGAC cylinders and 70 CFRP-confined RGAC cylinders.The key variables investigated include: replacement ratio of RGA,CFRP jacket thickness and curing age of concrete.The test results show that both the strength and deformability of RGAC can be significantly enhanced by the CFRP confinement,as in FRP confined normal concrete.It can also restrain the expansion of the system due to the ASR(alkali-silicon reaction),reduce the adverse effects of the glass aggregate on the concrete and also provide protection to the constrained recycled glass aggregate concrete and increase its durability.Furthurmore,the FRP provides additional protection to the confined concrete core against the attacks of the harsh environment.Comparisions have been made between the predcitions of exisiting stress-strain model for FRP-confined normal concrete and the results presented in this study,paving the way for further theoretical study.This study also compares the prediction results of different theoretical models of FRP-confined concrete with the experimental test results,and tests the applicability and accuracy of the theoretical model,which lays a foundation for the subsequent theoretical analysis of CFRP-constrained recycled glass aggregate concrete.In addition,the microstructure of RGAC was obtained by SEM(scanning electron microscope)to study the microstrure of RGAC and compared with that of normal concrete.This study is of research significance and great application value as outcomes of the study enrich the research on FRP-confined concrete and promote the protential application RGAC(such as in structures).