Experimental Study On The Axial Compression Performance Of Rubber Recycled Concrete After Exposure To Elevated Temperatures

Rubber Recycled Concrete(RRC)is a new type of green building material.With good fatigue resistance,impact resistance and crack resistance,it makes up the poor deformation of recycled concrete,which has positive significance for the promotion of recycled concrete.Since the escape of rubber after high temperature increase the structural porosity and affect the mechanical properties of recycled concrete structures,we need to do further research.At present,the research on RRC mainly focuses on the mechanical properties and working performance at room temperature,but the research on the performance of RRC after high temperature is still relatively rare,and the related literature is also scarce.Based on the previous research,this paper selects RRC as the research object,and produces 108 cylindrical and 54 cubic concrete specimens to study the effect of recycled aggregate replacement rate,rubber content and temperature on the axial compression of RRC.(1)Axial compression tests are carried out on 27 cylindrical specimens at normal temperature to analyze the influence of different recycled aggregates replacement ratio(0%,50%,100%)and different rubber content(0%,2%,4%,6%)on the axial compression failure mode,stress-strain curve,compressive strength,Young's modulus,Poisson's ratio,toughness and specific toughness of RRC.(2)Axial compression tests are carried out on 81 cylindrical specimens after high temperature test to analyze the changes in the appearance of RRC with different recycled aggregates replacement ratio(0%,50%,100%),different rubber content(0%,2%,4%,6%)after different temperatures(200 ?,400 ?,600 ?).In addition,the variation of axial compression failure mode,mass loss,stress-strain curve,compressive strength,Young's modulus,toughness and special toughness is analyzed.(3)The RRC stress-strain curve without dimension after high temperature is fitted,and a constitutive equation of RRC after high temperature is proposed to provide a theoretical reference for its further research and reinforce.(4)The microstructure of RRC gel slurry after different temperatures is observed by electron microscopy.The mechanism of rubber improves the burst resist capability of RRC on fire is analyzed from the micro layer.