考虑基体混凝土水灰比影响的再生粗(细)骨料混凝土徐变模型

对现有再生混凝土徐变试验数据的研究发现，源于不同强度混凝土的再生细骨料对再生混凝土徐变的影响差异较大，而现有模型未计入该差异的影响。因此，基于课题组前期已提出的再生粗、细骨料混凝土徐变模型，引入水灰比系数考虑用于制造再生骨料的废弃混凝土(基体混凝土)强度对残余水泥石物理性质的影响，提出了考虑基体混凝土水灰比影响的再生粗、细骨料混凝土徐变通用模型。基于现有试验结果，对所提出的再生粗、细骨料混凝土徐变模型及已有模型预测结果进行了对比分析。研究表明，修正后的徐变通用模型精度高于已有徐变预测模型，且离散性较低。通过系统参数分析，研究了在工程常见的参数范围内，基体与再生混凝土强度、取代率、再生细骨料吸水率以及环境相对湿度对徐变的影响。分析发现，基体混凝土强度、取代率、再生细骨料吸水率、环境相对湿度是影响再生混凝土徐变的关键参数。

Creep model for recycled coarse and fine aggregate concrete considering water-cement ratio of matrix concrete

Existing research shows that the inclusion of fine recycled aggregate (FRA) with different strength of matrix concrete has different influences on the creep behavior of recycled aggregate concrete (RAC). However, the available creep models do not account for the influence of matrix concrete strength on the creep of RAC.Thus, based on the existing creep model of RAC, this paper proposed a new general creep model by introducing the coefficient of water-cement ratio to account for the influence of matrix concrete strength on physical properties of residual cement paste. The predicted results of this model and other creep models were compared with the available creep tests of RAC. The comparative results show that the newly proposed model has the best performance in predicting the creep of RAC with the lowest scatter. Extensive parametric study was then performed to investigate the influence of commonly-used study parameters on the creep of RAC. It is shown that the strength of matrix concrete, the water absorption of FRA, the replacement ratio and the relative humidity are the key factors influencing the creep of RAC.