Rond Behavior Of Glass Aggregate Reinforced Concrete Under Complex Environment

Glass aggregate concrete(GAC)is a new type of concrete that uses broken glass to partially or completely replace the conventional coarse(river stone,gravel)and fine(river sand)aggregates.The bond performance between new concrete and reinforcement is the main research fields.Especially,the working environment of concrete structure is relatively complex.Therefore,the research on bond performance of GARC under complex environment has higher practical engineering significance.The GAFC with glass sand as the substitute was selected as the research object,and the aggregate replacement rate,freeze-thaw cycle times and chloride concentration were taken as variable parameters to study the bonding performance of GARC under the coupling action of freeze-thaw cycle,chloride corrosion,freeze-thaw cycle and chloride erosion.Furthermore,the bond constitutive model of GARC in complex environment is established.The work of this paper is as follows:(1)The slow freezing method and the improved electrochemical accelerated corrosion method were used to simulate the freeze-thaw cycle and chloride erosion environment.In addition,the freezing and thawing cycle and chloride corrosion coupling experiment were designed to further simulate the coupling environment of complex factors.The apparent damage was recorded,and the mass loss rate and corrosion rate of reinforcement were measured.(2)The central pull-out method was used to test the bond performance of specimens subjected.The failure mode,ultimate bond strength,peak slip,bond stiffness and bond slip curve were analyzed to explore the bond performance of glass aggregate matrix concrete in various complex environments.the bonding mechanism between GAC and steel bar in complex environment is analyzed and elaborated.(3)Based on the analysis and fitting of bond data,the degradation model of ultimate bond strength under the action of freeze-thaw cycle and chloride erosion is proposed,and the modified formula of anchorage length under the action of freeze-thaw cycle is given,and the constitutive model of GARC bond and anchorage under the action of freeze-thaw cycle and chloride corrosion is established respectively.The following conclusions are drawn:(1)Compared with NARC,the apparent damage degree and mass loss rate of glass aggregate reinforced concrete test group under freeze-thaw cycles are kept at a low level,and the corrosion degree of glass aggregate reinforced concrete under salt attack is lighter.Therefore,GARC has a high resistance effect on the complex environment.(2)During the coupling process,the mutual inhibition effect of freeze-thaw cycle and chloride corrosion gradually transformed to mutual promotion,so the apparent damage,mass loss and corrosion rate of the coupling effect at the initial stage were slightly better than those of single factor.(3)In the complex environment,when the aggregate replacement rate is between 0% and75%,the bond performance between glass aggregate concrete and reinforcement is still good,and the deterioration effect is significantly lower than that of natural aggregate concrete,and the bond performance increases with the increase of aggregate replacement rate.