不同侧压下再生混凝土与钢筋间黏结性能试验研究与理论分析

为研究不同侧压下再生混凝土与钢筋间的黏结 滑移性能，以再生粗骨料取代率、水灰比、侧向压力比为参数，完成了144个再生混凝土试件在单向、双向侧压作用下的钢筋中心拉拔试验，观察了再生混凝土试件的破坏形态，分析了上述参数变化对黏结强度、峰值滑移的影响；基于再生混凝土多轴破坏准则，推导了不同侧压作用下再生混凝土-钢筋的黏结强度理论模型及其简化公式。研究结果表明：再生混凝土中心拉拔试件的破坏形态与侧压力比明显相关，双向侧压力比较大时，试件破坏形态与单向侧压时破坏形态相似，当双向侧压力接近时，双向均有裂缝；黏结强度与峰值滑移随侧压力比的增大，整体呈现增加趋势；基于再生混凝土多轴强度理论的黏结强度计算值与实测值较为吻合，其简化计算公式能较好地预测不同侧压力下再生混凝土与钢筋间的黏结强度。

Test and theoretical study on bond behavior between recycled concrete and rebar under different lateral pressures

In order to study the bond-slip behavior between recycled concrete and rebar under different lateral pressures (LP), 144 pull out specimens were prepared and tested under axial and bi-axial LP with the replacement ratio of recycled coarse aggregate, water to cement ratio and lateral pressure ratio as the research parameters. The failure patterns of pull-out specimens were observed, and the effects of aforementioned parameters on bond strength, peak slip were analyzed. The theoretical calculation model for bond strength and its simplified formula under different LP were derived based on the multi-axial failure criterion of recycled concrete. The results show that the failure patterns of recycled concrete specimens are obviously related to the LP ratio; for specimens with high LP ratio, the failure pattern is similar with that of specimens with uniaxial LP, while for specimens with comparable bi-axial LP, the cracks can be observed along the bi-axial; the bond strength and the peak slip also increase with the increase of the lateral stress ratio. The calculated value of bond strength based on the multi axial strength theory of recycled concrete is consistent with the tested value, and the simplified calculation formula can be used to predict the bond strength between recycled concrete and rebar under different LP.