Experimental Study On Bond Performance Between Shale Ceramsite Concrete And Steel Bars After Elevated Temperature

With the rapid development of modern construction industry and the development and utilization of various new building materials,lightweight aggregate concrete has been widely used as a man-made material with high-strength and light weight.The combination of steel and concrete has been applied to various structural forms.Since the frequency of building fires has always been high,the reinforced concrete structure will be damaged under elevated temperature conditions.The bond performance between steel and concrete will be significantly degraded,which directly affect the safety and performance of concrete structures.Therefore,it is of great theoretical significance to study the bondage and anchorage properties of steel bars and concrete after fire to the detection,evaluation and reinforcement of concrete structures under actual fire.In this paper,the bonding behavior of shale ceramsite concrete and hot rolled crescent ribbed bar(CRB)after elevated temperature is study by the bonding test.The main research contents are as follows:(1)Based on the central pullout test of bonded anchor specimens of steel and shale ceramsite concrete after elevated temperature,the relationship between the bond strength and the type of shale ceramsite concrete,the type of steel bars,the diameter of steel bars,and heating temperatures were analyzed.And it studied the variation of the bonding and anchoring properties of CRB and shale ceramsite concrete under different conditions.(2)According to the statistical analysis of the experimental data,the calculation formula of the bond strength of LWSCC and CRB after different elevated temperature is obtained.(3)The bond failure process was analyzed from the energy point of view,and the total energy failure curves were obtained.The pre-peak energy consumption of different typr of shale ceramsite concretes were compared and analyzed.And the bond failure energy mechanism of shale ceramsite concrete was given.(4)According to the experimental data,the difference between the three equivalent models were analyzed,and the cost-effectiveness ratio and equivalent models are studied and compared to obtain the relationship of equivalent curvature radius and bond stress and cost-effectiveness ratio as the temperatures rises.