再生混凝土骨料咬合模型修正及其参数分析

为分析再生混凝土中再生粗骨料咬合机制，基于Walraven提出的普通混凝土骨料咬合模型，提出了考虑再生粗骨料原始混凝土强度的再生混凝土骨料咬合修正模型。结合再生混凝土界面剪切试验结果，确定适用于再生混凝土的骨料咬合模型关键参数。理论分析结果与试验结果对比表明，修正的骨料咬合模型对于界面剪切作用的预测值较普通混凝土及再生混凝土的试验值均偏高，修正的骨料咬合模型较适用于对再生混凝土剪切作用的预测。在再生混凝土剪切作用理论计算中，需按实际裂缝开展情况对骨料咬合作用进行折减，折减系数取值范围为0.7~0.9。采用修正的再生骨料咬合模型及计算方法展开变参数分析发现，再生粗骨料性能对骨料咬合作用有重要影响，即再生粗骨料原始混凝土强度越高，旧砂浆含量越低，再生粗骨料咬合作用越强。

Modification and parametric study on aggregate interlock model of recycled aggregate concrete

In order to analyze the aggregate interlock mechanism in recycled aggregate concrete (RAC), based on the aggregate interlock model for conventional concrete proposed by Walraven, the modified recycled aggregate interlock model considering the parent concrete strength of recycled coarse aggregate (RCA) was proposed. The calculation parameters for the recycled aggregate interlock model were determined with the reference of the experimental results for the interfacial shear test of RAC. Through the comparison between the theoretical calculation values and the test results, it is found that for both conventional concrete and RAC, the theoretical calculation values are higher than the test results. Compared with the theoretical calculation results for conventional concrete and RAC, the modified recycled aggregate interlock model is more suitable for the prediction of shear properties for RAC specimens in this experiment. A reduction factor ranging from 0.7 to 0.9 should be considered to account for crack propagation condition when predicting the shear properties of RAC specimens. The parametric study was conducted using the modified recycled aggregate interlock model and the calculation method. The results illustrate that the properties of RCA have a significant influence on the aggregate interlock behavior. The higher parent concrete strength of RCA and the lower content of old mortar contribute to the increase of the aggregate interlock performance.