Study On Bond Behavior Between Steel Bar And Cementitious Grouting Material After High Temperature

Cementitious grouting material because of its good performance is widely used in structural reinforcement. Thus research the properties of cementitious grouting material and the bond performance of reinforced cementitious grouting material after high temperature has important social significance and value.In this paper, the compressive strength and elastic modulus of cementitious grouting material after high temperature were tested, obtained the law of the influence of water addition ratio, high temperatures, curing period, cooling methods, elapsed times on mechanical properties of cementitious grouting material after high temperature;investigated the bond performance of reinforced cementitious grouting material under monotonic loading and low cyclic loading which had been heated to high temperature,conducted the influence of high temperature, curing period,cooling methods and transverse stirrups on the adhesive properties,the main research results obtained are as follows:The compressive strength of cementitious grouting material cured to 28 d after high temperature were studied. The influence law of the factors such as high temperature, curing period, cooling methods, elapsed time on compressive strength of cementitious grouting material were analyzed, and studied the differences of cementitious grouting material with different water addition ratios after high temperature. The variation law of the cementitious grouting material compressive strength with stewing time increasing was investigated.The results show that, the higher the temperature is, the greater loss cementitious grouting material strength get;it needs 7d when the loss of cementitious grouting material strength is minimum;Water spray cooling is beneficial to strength recovery of early age cementitious grouting material of high temperature;he properties of cementitious grouting materia after high temperatures would stabilize as long as extend the elapsed time.The elastic modulus of the cementitious grouting material prism after exposure to elevated temperature were tested, conducted the influence of water addition ratio,high temperature, curing period and cooling methods on the elastic modulus.The results show that,the elastic modulus of the cementitious grouting materia decreased with increasing water addition ratio;it needs 7d when the elastic modulus of the cementitious grouting materia reached a maximum;the higher the temperature is, the smaller the elastic modulus gets;In the early age elastic modulus of Water spray cooling specimen is better than the natural cooling specimen after high temperature.The bond performance of reinforced cementitious grouting material under monotonic loading after high temperature were studied,analyzed the influence of high temperature, curing period, cooling methods and transverse stirrups on the adhesive properties.The results show that,the higher the temperature is, the worse the bond performance of reinforced cementitious grouting material gets;it needs 7d when the loss of the bond performance of reinforced cementitious grouting material is minimum;Water spray cooling is more conducive than natural cooling to the self-recovery on adhesive properties of reinforced cementitious grouting material of temperature damage in early age of, but accelerated in the failure of high temperature specimens in 28d; The transverse stirrups increases the bonding property of reinforced cementitious grouting material.The bond performance of reinforced cementitious grouting material under low cyclic loading after high temperature were studied,analyzed the influence of high temperature, curing period, cooling methods and transverse stirrups on the ultimate bond stress and ultimate bond displacement of specimens,which is compared with the bonding performance under monotonic load.The results show that, the higher the temperature is, the smaller the ultimate bond stress of specimens get;it needs 7d when the bond performance of the specimens reached a maximum;water spray cooling is better than natural cooling on adhesive properties of early age specimens;the transverse stirrups increases the ultimate bond stress and ductility of specimens;The low cycle repeated load exacerbates the failure of bonded specimens.