Study on the Evaluation of Influence of Creep on Autogenous Shrinkage Stress

蠕变对自收缩应力影响的评价研究

基本信息

批准号：
09650506
负责人：
MORIMOTO Hiroaki
金额：
$ 1.28万
依托单位：
Gifu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650506/
关键词：
High strength concrete Autogenous shrinkage Young age Compressive creep Tensile creep Variable stress Method of superposition Effective Young's modulus 自己収縮

项目摘要

The following concepts were clarified on the compressive and tensile creep, the evaluation method of creep under changing stress and the calculation method of autogenous shrinkage stress of high strength concrete in early ages.1. Creep is proportion to a stress to the extent of 40 % of stress-strength ratio, at least.2. A significant difference is not recognized with compressive and tensile creep.3. Creep characterisitic changes greatly near by the age of 1 or 2 days, and the change is small after the age of 3 days.4. Basic creep function for high strength concrete in early age can be given by the product of final creep value and creep progress function.5. Creep value right after the stress reversal estimated by the method of superposition is grater than the measured a little, yet the estimated value generally agree well with the measured value.6. There are no remarkable differences between the estimated values by the time hardning rule and the strain hardning rule, and the estimated vales are fairly small compared with the measured value, especially right after the stress reversal.7. The time hardining rule and the time hardning rule require some appropriate correction considering the softning due to the stress reversal.8. The autogenous shrinkage stress of 1.5N/mmィイD12ィエD1 at the age of 7 days and 2.2N/mmィイD12ィエD1 at the age of 60 days were measured by using JCI method in high strength concrete having water-cement ratio of 30%.9. The autogenous shrinkage stress can be estimated by the increment method using the effective Young's modulus calculated from measured creep coefficient of high strength concrete having water-cement ratio of 30%.10. The Young's modulus reduction coefficient for calculation of autogenous shirinkage stress is a little smaller than that for thermal stress calculation

在压缩和拉伸蠕变，应力变化下的蠕变方法以及高强度混凝土高强度混凝土的自动收缩应力的计算方法上阐明了以下概念。1。蠕变与应力的比例至少达到应力强度比的40％。2。压缩和拉伸蠕变未识别出一个显着差异3。蠕变特征的变化很大，到1或2天的年龄差不多，并且3天后的变化很小。4。最终蠕变值和蠕变进度功能的乘积可以给出高强度混凝土的基本蠕变功能。5。在应力逆转通过叠加方法估计的应力逆转之后的蠕变值比测得的一点略微，但估计值通常与测得的值很好地一致。6。按时间缩写规则和应变硬化规则，估计值之间没有显着的差异，与测量值相比，估计值相当小，尤其是在应力逆转之后。7。考虑到由于压力逆转而导致的软化，时间硬化规则和时间硬化规则需要进行一些适当的校正。8。使用JCI方法以30％0.9的高强度混凝土中的高强度混凝土测量，在7天的7天时代的自体收缩应力为1.5N/mMY D12和60天的2.2n/mmy d12。自体收缩应力可以通过增量方法估算使用有效的Young的模量，该模量是根据测量的高强度混凝土蠕变芯计算得出的，水泥浆比为30％.10。杨氏模量降低核心用于计算自体闪电应力的核心比热应力计算小一点