摘要
对早龄期高性能混凝土的拉伸徐变特性把握,能够为高精度的应力解析及开裂预测提供重要参数.以水灰比为0.3的高性能混凝土为研究对象,利用自行设计的早龄期拉伸基本徐变实验装置,探讨了不同加载龄期(0.5,0.75,1,3和7 d)及不同加载初始应力强度比(0.2、0.3和0.4)下的拉伸徐变特性.实验结果表明:龄期0.5,0.75和1 d加载的混凝土表现出较高的徐变能力,并且徐变速度在持荷一段时间后随龄期的推迟而急剧下降.龄期0.5,0.75 d加载的混凝土徐变表现出较大的非线性,并且对同一个加载龄期,加载初始应力强度比越大,比徐变越大,并且加载初期的徐变速度越快;但加载龄期在1,3,7 d的混凝土徐变仍表现出线性特征.
The understanding of tensile creep behavior contributes considerably to the highly accurate stress analysis and crack prediction in high performance concrete. This paper deals with the experimental investigation on tensile creep of high performance concrete with water cement ratio of 0.3 at early ages. A set of early-age tensile basic creep testing apparatus was constructed, and the behavior of tensile creep under different loading ages （0.5, 0.75, 1, 3 and 7 days） and stress /strength ratio （0.2, 0.3 and 0.4） were discussed. The results of the experiment indicated that： firstly, a particularly high magnitude of tensile creep stain was observed when concrete was loaded at 0.5, 0.75 and 1 days, and the creep rate decreased dramatically after a short initial time under load . Secondly, Tensile creep was not proportional to applied stress when the loading age is 0.5, 0.75 days, and the higher initial stress/strength ratio, the larger specific creep strain and creep rate. However, it appeared characteristic of linearity when concrete was loaded at 1, 3 and 7 days.
出处
《浙江工业大学学报》
CAS
2008年第3期285-289,共5页
Journal of Zhejiang University of Technology
基金
浙江省自然科学基金资助项目(Y106856)
关键词
拉伸徐变
高性能混凝土
加载龄期
应力强度比
早龄期
tensile creep
high performance concrete
age at loading
stress/strength ratio
early ages
