Compressive Behavior Of Polyester FRP-PVC Tube Encased Recycled Aggregate Concrete(RAC) With Partially Recycled Clay Brick Aggregate(CBA)

Recycled aggregate concrete(RAC)is a new kind of construction material,which is made of recycled aggregates from construction and demolition waste(waste concrete,waste brick and so on)instead of natural aggregates.The development of recycled aggregate concrete is an important way to promote recycling economy,achieve sustainable development of construction industry,and build a resource-efficient and environment-friendly society.Because the properties of recycled aggregates are distinctly different from those of natural aggregates,recycled aggregate concrete(RAC)has the characteristics of low strength,poor ductility and poor durability compared with natural aggregates concrete(NAC).With advantages of light weight,high strength and convenient construction,the fiber-reinforced plastic(FRP)has been widely used in the confined concrete to improve the performance of concrete.The traditional FRP materials,such as the carbon fiberreinforced plastic(CFRP)and the glass fiber-reinforced plastic(GFRP),are expensive in production.Besides,the abandoned inorganic FRP is hard to decompose,leading to the low recycling rate of traditional FRP.As an organic composite textile fiber with the highest output in the world,the polyester fiber is characterized by a favorable material performance,low cost,extensive sources,easy recycling and environmental-friendly.All these characteristics of the polyester fiber suggests that the polyester fiber can replace the traditional fibers and be used to fabricate FRP,to some extent.Some scholars have already applied the polyester fiber-reinforced plastic(PFRP)in the field of engineering reinforcement.Polyvinyl chloride(PVC)is an extensively-used architectural material,which is known for its favorable mechanical performance and strong resistance against corrosion.This thesis proposes the method to fabricate the PFRP-PVC composite materials with the PFRP and PVC tubes as raw materials.The PFRP-PVC composite materials are used to confine the recycled aggregate concrete with brick aggregate for the purpose of improving mechanical performance and durability of the recycled aggregate concrete.The compression performance of the recycled concrete is verified through the experiment and theoretical analysis.Below is a brief introduction of the research work in this thesis:(1)Experimental research of the mechanical performance of PFRP,PVC materials and the core concrete,including: The tensile properties of PFRP materials of different layers;the tensile properties of PVC materials adopted;and the compressive strength of recycled aggregate concrete with partially recycled clay brick aggregate(termed as RAC-RCBA).(2)Experimental research of the axial compressive performance of PFRP-PVC tube encased RAC-RCBA: 36 cylindrical specimens with the diameter of 152 mm and the height of 305 mm were tested under axial load.The experimental parameters include the number of PFRP(3 layers,6 layers or 9 layers);the packaging form of PFRP(tube or strip);and spacing distance of PFRP strip(25mm or 50mm).(3)Analysis of the calculated model of PFRP-PVC tube encased RAC-RCBA: The compressive characteristics of PFRP-PVC confined concrete were analyzed,regression analysis of experimental data was conducted so as to build the peak stress and peak strain model of the PFRP-PVC tube encased RAC-RCBA.Based on regression analysis of the strength and ultimate strain models,this thesis put forward the ultimate stress and strain models.(4)Research on the constitutive relation model of the PFRP-PVC tube encased RAC-RCBA: The existing constitutive relation models are introduced.The experimental results of this thesis were compared with the calculated results of the existing models.The regression analysis is conducted to modify the original model with a small error.The constitutive relation model of the PFRP-PVC tube encased RAC-RCBA with a smaller error is obtained.