氯盐环境与荷载耦合作用下加载龄期对钢筋混凝土柱徐变影响  

Study on effect of loading age on creep of reinforced concrete columns under coupled action of chloride environment and load

作　　者：曹国辉[1] 王礼彬 张展维 CAO Guohui;WANG Libin;ZHANG Zhanwei(College of Civil Engineering,Hunan City University,Yiyang 413000,China;College of Civil Engineering,Changsha University of Science&Technology,Changsha 410000,China;College of Civil Engineering and Mechanics,Xiangtan University,Xiangtan 411105,China)

机构地区：[1]湖南城市学院土木工程学院,湖南益阳413000 [2]长沙理工大学土木工程学院,湖南长沙410000 [3]湘潭大学土木工程与力学学院,湖南湘潭411105

出　　处：《建筑结构学报》2022年第6期275-283,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(51551801)。

摘　　要：为研究氯盐环境与荷载耦合作用下钢筋混凝土柱的徐变效应,在持荷与氯盐腐蚀环境下,对18根早龄期与标准龄期钢筋混凝土柱进行了202 d的长期试验,钢筋锈蚀率分别为0%、10%、20%,测试了早龄期混凝土柱在轴压、小偏压、大偏压三种受力状态下的徐变行为,并与相同条件下标准龄期混凝土柱的徐变行为进行了对比。结果表明:钢筋锈蚀率为10%时,锈蚀RC柱的徐变系数略低于未锈蚀RC柱的;钢筋锈蚀率为20%时,锈蚀RC柱的早期徐变系数偏低,而后期徐变系数出现较快且持续的增长;受混凝土黏性流动和钢筋锈蚀影响,早龄期RC柱的徐变系数低于理论值。根据钢筋实际锈蚀状况,拟合了钢筋锈蚀率分布函数,并通过黏结退化系数得出对应的徐变折减系数,提出修正的ACI209R徐变模型。通过与试验数据进行对比分析,该修正徐变模型的预测效果较好。当锈蚀率为10%时,模型可靠性高;当锈蚀率为20%时,在持载早期,模型计算值较实测值偏高,但后期两者的差值较小。Long-term tests of 202 days were performed on 18 early-age or standard-age reinforced concrete columns to investigate the creep effect of reinforced concrete columns under the coupled action of chloride environment and load. The percentage of corrosion of reinforcing bars are 0%, 10%, and 20%, respectively. In addition, the creep of early-age concrete columns under axial, small, and large eccentric compression was tested, and the measured data are compared to that of standard-age concrete columns. The results show that the creep coefficients of corroded specimens are slightly lower than that of uncorroded ones when the percentage of corrosion is 10%. When the percentage of corrosion is 20%, the creep coefficients of corroded specimens are lower than uncorroded specimens initially and increase rapidly and continuously later. Affected by the viscous flow of the concrete and the corrosion of the steel bar, the test results of creep coefficients of the early-age specimens are lower than the theoretical values. The distribution function of corrosion rate is fitted based on the actual corrosion status of the steel bar, and the corresponding creep reduction coefficients are obtained by the adhesion degradation coefficient. The modified ACI-209 R creep model is proposed. Compared with the experimental value, the modified creep model has a good prediction performance. When the percentage of corrosion is 10%, the model has high reliability. When the percentage of corrosion of the specimen is 20%, the calculated value of the model is higher than the measured value in the early stage of load, but the error is lower in the subsequent loading stage.

关 键 词：RC柱 早龄期混凝土 钢筋不均匀锈蚀 静力试验 徐变 

分 类 号：TU375[建筑科学—结构工程] TU317.1