配筋高性能混凝土收缩徐变试验研究  

Experimental Study on Creep and Shrinkage of High-performance Reinforced Concrete

作　　者：张运涛[1,2] 孟少平[1] 惠卓[1] 

机构地区：[1]东南大学混凝土及预应力混凝土结构教育部重点实验室,南京210096 [2]安徽建筑工业学院土木工程学院,合肥230022

出　　处：《建筑科学》2010年第3期1-5,共5页Building Science

基　　金：江苏省交通科学研究计划项目(05y02)

摘　　要：为获得苏通大桥连续刚构桥所用高强高性能混凝土的收缩徐变规律,在自然环境下开展了为期两年多配筋混凝土(配筋率分别为0、0.38%、0.76%和1.71%)的收缩徐变试验。徐变试件加载应力水平约为15MPa,与实桥最大应力水平相近。加载龄期有四种,分别为7d、14d、21d和28d,分别模拟了实桥节段施工混凝土的加载龄期。在收缩徐变试验基础上拟合出收缩徐变曲线。试验结果表明,实桥所用高强高性能混凝土的收缩徐变小于现行桥梁规范JTGD62-2004取值,配筋混凝土的收缩徐变小于素混凝土的收缩徐变。采用有限元软件ANSYS/CivilFEM分析了配筋对混凝土收缩徐变的影响,分析结果和试验结果一致:当配筋率较低时,配筋对混凝土的收缩徐变影响较小,在工程应用范围内,可以不考虑配筋的影响;当配筋率较高时,配筋可以有效地减小收缩徐变的发展。研究成果可为实桥主梁时变分析提供参考依据。In order to obtain shrinkage and creep properties of high-performance concrete（HPC） used in Sutong continuous rigid-frame bridge,the shrinkage and creep of plain concrete and reinforced concrete（reinforcement ratio from 0.38%,0.76% to 1.71%） were investigated under natural environment over two years.Loading stress of creep test is about 15MPa,which is also near the maximum stress of the bridge.Four loading ages of 7d,14d,21d and 28d respectively were used to simulate the different loading ages in construction.The curves of creep and shrinkage are fitted from test values.The results show that the test values of creep and shrinkage are smaller than the values set in the current bridge code（JTG D62-2004）,and the creep and shrinkage of reinforced concrete is less than that of plain concrete.The finite element software ANSYS/Civil FEM has been applied to analyze the influence of steel bar restraint on creep and shrinkage,and the analysis results are in good agreement with the experiment results.If the reinforcement ratio is low,the steel bar exerts less influence on creep and shrinkage.So the influence of reinforcement can be neglected in engineering application.However,the reinforcement can effectively reduce creep and shrinkage development if the reinforcement ratio is high.This research would provide the basis and reference for the time dependent analysis of main girder.

关 键 词：高性能混凝土 配筋混凝土 收缩 徐变 

分 类 号：TU528[建筑科学—建筑技术科学] TU528.31