Study On High Temperature Damage Of ALWC And SLWC

Lightweight aggregate concrete has good properties of lightweight and high strength,thermal insulation,seismic and fire antifreeze,which is widely used in high-rise buildings,large-span structure and other key engineering.With the frequent occurrence of building fires,higher requirements for ductility and fire resistance of building materials have been put forward.It has been found that adding fiber into lightweight aggregate concrete can improve the mechanical properties of concrete.At present,most of the studies on properties of lightweight aggregate concrete is in normal state,it can only reflect the stress state at room temperature,the properties of lightweight aggregate concrete after high temperature curing,the domestic research is relatively small,and the summer is very hot,in some places,the outdoor temperature can reach 40?,often in the sun under the condition of direct,concrete surface temperature can reach 50?,or even higher.Taking LC30 for an example,this paper studies the mechanical property deterioration of the general mechanical properties and high temperature after high temperature curing of lightweight aggregate concrete after lightweight aggregate concrete,analyzes the damage mechanism of different temperature on lightweight aggregate concrete,the main research contents are as follows:(1)The experimental studies on the general mechanical properties of lightweight aggregate concrete after high temperature curing,analysis the different age and different curing temperature after different characteristics of lightweight aggregate concrete strength,elastic modulus and stress strain curves,and comparative analysis of the mechanical properties of room tem perature curing.(2)The experimental studies on the deterioration performance of lightweight aggregate concrete after curing at 28 ambient temperature and experiencing the target high temperature.The influence of temperature on its macro mechanical properties and the deterioration trend after high temperature are analyzed,and how to add fiber to improve the burst performance and high temperature performance of lightweight aggregate concrete.(3)By using scanning electron microscopy(SEM)micro structure test of lightweight aggregate concrete,to observe the micro morphology of different temperature on lightweight aggregate concrete,and the change of gel pore structure changes of the situation;(4)Through observation the surface color change,cracks and internal pore structure changes of concrete after high temperature,to explore the characteristics of high temperature damage,respectively,analysis its damage mechanism from the macro,micro aspects,and compare with the micro-structure of concrete at normal temperature curing.