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Modeling of Creep Properties of concrete at Early Ages

早期混凝土蠕变特性的建模

基本信息

批准号：
02805056
负责人：
TSUBAKI Tatsuya
金额：
$ 1.41万
依托单位：
Yokohama National University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02805056/
关键词：
Concrete Creep Early Ages Mechanical Properties Modeling Statistical Variation 構成則

项目摘要

In this study, the following experiment and numerical analysis were conducted to investigate the creep property of concrete at early ages and to examine the basic factors necessary for its modeling.1. Concrete is considered as a composite material made up of mortar and coarse aggregates. Then, mortar is the part which deforms due to creep. Therefore, uniaxial creep tests in compression were conducted for mortar specimens at early ages. The drying creep strain and the basic creep strain were measured in those tests. The age at loading was less than 24 hours. Choosing age of mortar, ratio of stress to strength, and water-cement ratio as the influencing factors, their influence on creep strain of mortar was estimated from the test results. In the test, surrounding temperature and humidity were kept constant (20ﾟC, 70% RH) in a computer-controlled chamber.2. The method of modeling to deal with the large statistical scatter involved in the creep of concrete was investigated. The effectivene … More ss of the concept of a probabilistic model to the modeling of the mechanical property with a large statistical variation was confirmed through numerical simulations using a practical design formula as a part of the constitutive model.3. A kind of complex element called concrete element based on the finite element method was developed to investigate the influence of the size and the spatial distribution of coarse aggregates on the creep and shrinkage of concrete. in this case, concrete is modeled as a composite material made up of mortar and coarse aggregates in the structural level of coarse aggregates. The effectiveness of the concept of a concrete element to the numerical analysis of such an internal structure of concrete was confirmed through various numerical simulations on the deformational behavior of concrete.The creep test for concrete specimens based on this basic study and the investigation of the creep of concrete of actual structures may be considered as the extension of the present study. Less

在本研究中，进行以下实验与数值分析，以探讨混凝土在早期的徐变特性，并检查其建模所需的基本因素.混凝土是由砂浆和粗骨料组成的复合材料。然后，砂浆是由于蠕变而变形的部分。因此，在压缩单轴蠕变试验在早期的砂浆标本进行。在这些试验中测量了干燥蠕变应变和基本蠕变应变。加载时的老化时间小于24小时。选取砂浆龄期、应力强度比和水灰比作为影响因素，根据试验结果估算了它们对砂浆徐变应变的影响。在测试中，周围的温度和湿度保持恒定（20 ° C，70%RH）在一个计算机控制的房间。研究了混凝土徐变过程中统计离散性较大的建模方法。有效性 ...更多信息通过使用实际设计公式作为本构模型的一部分的数值模拟，证实了概率模型的概念对于具有大的统计变化的力学性能的建模的适用性.为了研究粗骨料的尺寸和空间分布对混凝土徐变和收缩的影响，在有限元法的基础上建立了一种复杂的混凝土单元。在这种情况下，混凝土在粗集料的结构水平上被建模为由砂浆和粗集料组成的复合材料。通过对混凝土变形行为的各种数值模拟，证实了混凝土单元概念对这种混凝土内部结构的数值分析的有效性，在此基础上进行的混凝土试件徐变试验以及对实际结构混凝土徐变的研究可视为本研究的延伸。少