钢管再生混凝土徐变预测模型的确定及应用  

Prediction model on creep of recycled aggregate concrete filled steel tube

作　　者：陈杰[1] 耿悦[2] 王玉银[2] 

机构地区：[1]哈尔滨工业大学土木工程学院,黑龙江哈尔滨150090 [2]哈尔滨工业大学结构工程灾变与控制教育部重点实验室,黑龙江哈尔滨150090

出　　处：《建筑结构学报》2014年第4期280-288,共9页Journal of Building Structures

基　　金：国家自然科学基金面上项目(51178146);哈尔滨工业大学"985工程"青年学者基础科研能力建设项目

摘　　要：针对现有再生混凝土徐变预测模型仅考虑再生骨料砂浆含量对再生混凝土徐变特性的影响,未计入由基体混凝土水灰比所引起的再生混凝土徐变性能的差异,在分析影响再生混凝土徐变特性主要因素的基础上,提出了考虑基体混凝土水灰比的改进再生混凝土徐变预测模型。共收集39组再生混凝土徐变试验数据,将各再生混凝土徐变模型的预测结果与试验结果进行对比。研究表明,文中所提出的再生混凝土徐变预测模型可更好地反映再生混凝土的徐变特性,当基体混凝土水灰比与新配制的再生混凝土水灰比间存在差异时,采用所提出的模型预测再生混凝土徐变变形具有更高的精度。采用不同模型预测4组8个不同加载龄期钢管再生混凝土短柱的徐变变形,通过试验数据进行对比,验证了所提出的再生混凝土徐变模型在预测钢管再生混凝土轴压构件长期静力性能时的可靠性,其中4组试件采用较低强度基体混凝土配制的较高强度的再生混凝土。结果表明,当假设混凝土体积无穷大时,采用所提出的再生混凝土徐变预测模型进行钢管再生混凝土轴压构件的徐变分析,分析结果与试验结果相差不超过8%,其分析精度高于其他再生混凝土徐变预测模型。This paper intends to propose the creep model for recycled aggregate concrete filled tube （RACFST）, which is based on the concrete model with the capability of well predicting the time-dependent behavior of recycled aggregate concrete （RAC）. Existing concrete models for RAC only consider the influence of the amount of residual cement mortar attached on the recycled aggregate on the creep of concrete, without considering the effect of the water-cement ratio of the origin concrete. Based on the analytical results, the important factor which influences time effects of RAC was specified to propose a modified model considering the water-cement ratio of the original concrete. All the concrete models for RAC were benchmarked against 39 available creep tests to evaluate the reliability of those models in predicting the creep of RAC. It is indicated that the modified model proposed in this paper has the best performance in estimating the creep of RAC members whose water-cement ratios are different from those of original concrete. In order to verify the reliability of the proposed model in predicting the long-term responses of RACFST, the creep models were benchmarked against the long-term tests on eight RACFST stub columns under axial loading with different loading ages. The strength of RAC core in the experiments was higher than that of original concrete. When predicting the test results, the age-adjusted effective modulus method was employed by adopting an infinite notional size for the concrete component to eliminate the effects of relative humidity. It can be noted that the modified model proposed in this paper also has the best accuracy in predicting the creep of RACFST with the maximum deviation within 8%, which can be applied in the analysis of long-term responses for such member in the practical engineering.

关 键 词：钢管再生混凝土 徐变 混凝土模型 轴心受压 

分 类 号：TU398.9[建筑科学—结构工程]