约束状态下混凝土拉伸徐变模型

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清华大学辅仁网/2017-07-07

约束状态下混凝土拉伸徐变模型

魏亚(

),姚湘杰

Tensile creep model for concrete subject to constant restraints

Ya WEI(

),Xiangjie YAO

Key Laboratory of Civil Engineering Safety and Durability of the Ministry of Education of China, Department of Civil Engineering, Tsinghua University, Beijing 100084, China

摘要:

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摘要为准确计算混凝土收缩变形在受到内、外部约束情况下产生的拉应力,评估混凝土收缩开裂风险、提高结构物耐久性,该文基于浇筑后混凝土的约束应力及应变试验,研究了混凝土约束状态下的拉伸徐变行为。研究结果表明: 约束状态下的混凝土具有较大的流动徐变变形,建立在压缩徐变试验基础上的传统徐变模型不能够精确预测约束状态下混凝土的应力发展。研究根据混凝土实测约束应力应变数据对传统模型进行改进,建立了更能代表实际工程情况、能够用于混凝土约束应力计算的徐变及松弛模型。

关键词 ：混凝土,收缩变形,约束应力,拉伸徐变,流变

Abstract：Tensile stresses develop in restrained concrete slabs with shrinkage deformation. The appropriate creep or relaxation functions are crucial for assessing the stress development and the associated cracking potential. Existing creep models were found not suitable for such stress evaluations. This study investigates restrained slabs stress-strain characteristics and tensile creep behavior in axially restrained concrete specimens which represent field conditions of actual structures. A modified tensile creep compliance function is used to account for the high viscous effect with restrained conditions for accurate predictions of the stress and cracking potential in structures.

Key words：concrete shrinkage deformation restrained stress tensile creep flow strain

收稿日期: 2012-07-02 出版日期: 2015-09-03

ZTFLH:

基金资助:国家自然科学基金资助项目 (51108246)

引用本文:

魏亚, 姚湘杰. 约束状态下混凝土拉伸徐变模型[J]. 清华大学学报（自然科学版）, 2014, 54(5): 563-567.
Ya WEI, Xiangjie YAO. Tensile creep model for concrete subject to constant restraints. Journal of Tsinghua University(Science and Technology), 2014, 54(5): 563-567.

链接本文:

http://jst.tsinghuajournals.com/CN/或 http://jst.tsinghuajournals.com/CN/Y2014/V54/I5/563

图表:

系列	混凝土组分/(kg分比^-3)					养护、测试温度/℃
系列	水泥		水	砂	石	矿渣
O23	451	203	1 143	402	0	23
O33	451	203	1 143	402	0	33
G23	316	203	1 143	402	135	23
G33	316	203	1 143	402	135	33

混凝土配合比

混凝土约束应力试验示意图

混凝土温度、应变、应力发展曲线示例

实测混凝土的应力-应变-强度发展曲线

基于实测应力采用不同徐变模型预测的收缩变形

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