This paper discusses the effect of the compressive and tensile strength of inorganic polymer concrete (IPC), protection layer thickness and bonded length of reinforcing bars (rebars) on the bond performance between IPC and rebars through laboratory tests of IPC at high temperatures. In addition, the bond performances of IPC and ordinary concrete at high temperatures are compared. The experimental results indicate that IPC at high temperatures exhibits superior bond performance with rebar compared with ordinary concrete. As the temperature increases, the reduction in the IPC-rebar bond strength exhibits similar behavior as the reduction in the compressive and tensile strengths of IPC. Thin protection layers contribute to significant degradation of the IPC-rebar bond strength at high temperatures. The degradation of the bond strength is affected by the rebar bonded length at room temperature but is not influenced at high temperatures. The analytical expression of the IPC-rebar bond strength at high temperatures can be derived by best fitting the experimental results. Based on the expression of the ultimate bond strength and the expression of rebar slip, a two-segment regression analysis is performed to obtain the local bond-slip relationship of rebars in IPC after exposure to high temperatures. This study provides theoretical contributions to the engineering application of IPC.
This study conducts an experimental program to calibrate a proposed arch resistance model that can be used to evalu-ate the residual axial load-carrying capacities of shear-damaged reinforced concrete (RC) columns. An extreme dam-age pattern of shear-damaged RC columns in which the axial load is carried by the longitudinal bars only due to spalling of the concrete core is considered in the experimental program. To simulate this extreme damage pattern, five bare specimens with different clear lengths are fabricated using only steel bars and tested to axial collapse under different axial loads. Based on the experimental results, the force-displacement behavior, limit state of the axial collapse, and stress state of the longitudinal bars of the shear-damaged RC columns are investigated for the proposed arch resistance model. The ratios of the analytical to the measured residual axial capacities in the designed specimens are between 0.77 and 0.92, demonstrating the high accuracy of the proposed model. In addition, the effects of post-yield strain hardening of the longitudinal bars on the force-displacement behavior and on the accuracy of the residual axial capacities of the shear-damaged RC columns are discussed.