摘要
为了得到早龄期混凝土在不同应力状态下的徐变发展规律,设计了3种设备用于测试早龄期混凝土在压缩、拉伸和弯曲作用下的徐变变形。文章分析了在加载龄期均为7天时,水灰比、环境湿度以及应力状态对早龄期混凝土徐变的影响。水灰比分别选取0.3,0.4,0.5;环境湿度分别为密封和暴露于50%湿度的干燥环境;应力状态包括压缩、拉伸、弯拉。基于测试结果定量分析不同水灰比、不同环境湿度以及不同应力状态下早龄期混凝土的徐变差异,并与文献数据进行对比。结果表明,在试件分别受到压缩、拉伸、弯拉荷载时,50%湿度的干燥环境状态下混凝土的早龄期徐变均大于密封条件下混凝土的早龄期徐变,干燥状态下徐变度约为密封状态下徐变度的1.25~2.5倍。相比于压缩徐变,拉伸徐变对环境湿度更敏感。受拉伸荷载时,干燥状态下徐变度约为密封状态下徐变度的1.75~2.5倍。受压缩荷载时,干燥状态下徐变度约为密封状态下徐变度的1.25~1.5倍。从数值上来看,不同水灰比试件的基本压缩徐变均大于基本拉伸徐变,基本压缩徐变与基本拉伸徐变之比在1.26~1.5之间。密封状态下,早龄期混凝土的压缩徐变最大、弯拉徐变次之、拉伸徐变最小。
To obtain the creep development rule of early-age concrete under different stress conditions,we designed 3 devices to measure the creep deformation of early-age concrete under compressive,tensile and flexural loadings.The influences of water-cement ratio,environmental humidity and stress condition on early-age concrete creep at the loading age of 7 days are analyzed.The water-cement ratio is 0.3,0.4 and 0.5 respectively.Ambient humidity is sealed and dry environment exposed to 50%humidity.The stress states include compression,tension and flexure.The creep differences of early-age concrete under different water-cement ratios,different ambient humidities and different stresses are quantitatively analysed based on the measuring result,which are also compared to those in the literature.The result shows that(1)When the specimens are subjected to compressive,tensile and flexural loads respectively,the early-age creep of the concrete exposed to 50%humidity drying condition is higher than that under sealed condition,the creep in dry state is about 1.25-2.5 times of that in sealed state.Tensile creep is more sensitive to ambient humidity than compressive creep.(2)Under tensile load,the creep in dry state is about 1.75-2.5 times of that in sealed state.(3)Under compressive load,the creep in dry state is about 1.25-1.5 times of that in sealed state.(4)In numerical terms,the basic compressive creep of specimens is greater than the basic tensile creep under different water-cement ratios,and the ratio of basic compressive creep to basic tensile creep is between 1.26 and 1.5.(5)Under sealed condition,the compressive creep of early-age concrete is the largest,the flexural creep is the second,and the tensile creep is the least.
作者
李庶安
魏亚
徐飞萍
李大方
韩兆友
LI Shu-an;WEI Ya;XU Fei-ping;LI Da-fang;HAN Zhao-you(Shandong Hi-speed Co.,Ltd.,Jinan Shandong 250101,China;School of Civil Engineering,Tsinghua University,Beijing 100084,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2020年第2期63-69,共7页
Journal of Highway and Transportation Research and Development
关键词
桥梁工程
徐变比较
压缩拉伸徐变比
早龄期混凝土
干燥徐变
road engineering
creep comparison
compressive creep/tensile creep
early-age concrete
drying creep
