干湿交替环境下氯盐侵蚀混凝土徐变试验研究  

Experimental Study on Chloride Eroded Concrete Creep in Dry-wet Circulation Environment

作　　者：陶志仁 龙煜 廖鹏飞 彭建新[1,2] TAO Zhi-ren;LONG Yu;LIAO Peng-fei;PENG Jian-xin(Key Laboratory of Bridge Engineering Safety Control of Ministry of Education,Changsha University of Science&Technology,Changsha,Hunan 410114,China;School of Civil Engineering,Changsha University of Science&Technology,Changsha,Hunan 410114,China;Hunan Tianzhu Liujian Concrete Co.,Ltd.,Changsha,Hunan 410000,China;Hunan Provincial Expressway Group Limited,Changsha,Hunan 410022,China)

机构地区：[1]长沙理工大学桥梁工程安全控制教育部重点实验室,湖南长沙410114 [2]长沙理工大学土木工程学院,湖南长沙410114 [3]湖南天筑六建混凝土有限公司,湖南长沙410000 [4]湖南省高速公路集团有限公司,湖南长沙410022

出　　处：《公路交通科技》2024年第10期112-119,共8页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(52078056);长沙理工大学桥梁工程安全控制教育部重点实验室开放基金重点项目(14KB01);长沙理工大学研究生科研创新项目(CXCLY2022036);桥梁结构健康与安全国家重点实验室开放基金项目(BHSKL20-07-GF)。

摘　　要：为准确预测干湿交替氯盐侵蚀环境作用下混凝土结构的徐变行为,通过开展干湿交替环境下氯盐侵蚀混凝土的徐变试验,研究了在氯盐侵蚀环境和轴压荷载耦合作用下,加载龄期、荷载水平对C50混凝土棱柱体试件徐变的影响。研究结果表明:7 d龄期加载时,氯盐环境下0.2fc,0.3fc荷载水平对应的混凝土徐变系数在持荷120 d前与常规环境接近,持荷120 d后较常规环境大,0.4fc荷载水平对应的徐变系数在持荷20 d后大于常规环境;28 d龄期加载时,两种不同环境下的混凝土徐变十分接近,持荷后期氯盐环境下的徐变系数略大于常规环境,早龄期加载时氯盐侵蚀导致混凝土性能的劣化,较高轴压荷载水平加速劣化;荷载水平在0.2fc~0.4fc范围内时,常规环境下混凝土的徐变为线性徐变,氯盐环境下混凝土徐变系数随荷载水平的增大先略减小后增大,呈现非线性徐变行为,这与轴压荷载影响氯盐侵入混凝土的速率,进而影响氯盐侵蚀混凝土导致其性能劣化的进程有关。基于试验数据,针对氯盐侵蚀环境,对JTG 3362—2018徐变预测模型提出了参数建议值。模型参数修正后的徐变系数计算值与试验数据吻合良好,可为预测C50混凝土在干湿交替氯盐侵蚀环境下的徐变行为提供参考。To accurately predict the concrete structure creep behavior in dry-wet circulation chloride erosion environment,the creep test was carried out for the concrete in dry-wet circulation chloride erosion environment.The influence of loading stages and loading levels on the creep of C50 concrete prism specimens under the coupling effect of chloride erosion and axial compression load was studied.The result indicates that in the chloride erosion environment,when loading at the 7th day,the creep coefficients with 0.2 f c and 0.3 f c(f c is the concrete axial compressive strength)loads are similar to those in the conventional environment within 120 days;but exceeding after 120 days.The creep coefficient with 0.4 f c load surpasses the coefficient in conventional environment after 20 days.At the 28th day of loading,the concrete creep behaviors in both environments are similar.The chloride erosion environment shows slightly higher creep coefficients in later stages.Chloride erosion accelerates the concrete performance deterioration,particularly at higher levels of axial compression.In conventional environments,with loads between 0.2 f c and 0.4 f c,the creep is linear.The concrete creep coefficient in chloride salt environment decreases slightly at first and then increases with the increase of load level,showsing the nonlinear creep behavior.This is related to the influence of axial load on the chloride intrusion rate into concrete and on the concrete performance deterioration.Based on the test data,the creep prediction model parameters in the relevant standards are suggested according to the chloride erosion environment.The calculated values of creep coefficient with modified model parameters are in good agreement with the experimental data,providing the reference for predicting creep behavior of C50 concrete in the dry-wet circulation environment.

关 键 词：桥梁工程 徐变 试验研究 混凝土结构 氯盐侵蚀 轴压荷载 

分 类 号：U444[建筑科学—桥梁与隧道工程]