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Method for Evaluation of In-place concrete Strength using Concrete Temperature History.

使用混凝土温度历史评估现浇混凝土强度的方法。

基本信息

批准号：
63850128
负责人：
MORITA Shiro
金额：
$ 7.62万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B).
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1990
项目状态：
已结题

项目摘要

It becomes more important to obtain information about the in-place strength of concrete as it exists in a structure especially for the use of high-strength concrete. As carried out in accordance with standard procedures, the test on cylinders only r13EA\ : epresents the potential strength of concrete as delivered to a site. A system for evaluation of in-place strength of concrete is proposed based on the methods developed in this research.(1) Evaluation on strength development accelerated by the hydration heat accumulation. The temperature in the high-strength concrete member rises about 40 degrees due to hydration heat. Various experiments were performed to clarify the effect of the13EA\ : high temperature histories during early age on accelerated strength development in early age and strength degradation in later age. On the basis of these test results, the practical method for evaluation of strength development was derived.(2) Analysis for temperature rise in concrete due to hydration heat. The examination on the temperature distribution in the concrete member obtained from tests shows that the dependency of hydration rate on temperature exists and it can be expressed13EA\ : by using Arrhenius equation. An analytical method considering this dependency was developed.(3) Application of pull-out tests for very high strength concrete. Pull-out tests on very high strength concrete were performed using specially improved test devices. The strength-predicting equation applicable for whole range of concrete strength w13EA\ : as derived.(4) Proposed method for evaluation of in-place strength. A method for determination of target strength at mix design is proposed based on the combination of the strength method and the analysis of temperature rise described in this study. A recommen13EA\ : ded method for evaluation of in-place strength is shown by applying the strength development theory and the pull-out test on concrete during construction.

由于混凝土存在于结构中，特别是对于高强度混凝土的使用，获得关于混凝土的现场强度的信息变得更加重要。按照标准程序进行的圆柱体试验仅r13EA\：e表示交付到现场的混凝土的潜在强度。基于本研究开发的方法，提出了混凝土现场强度评估系统。(1)水化热积累加速强度发展的评价。由于水化热，高强混凝土构件中的温度升高约40度。通过各种试验研究了13EA高温作用对早期强度发展和后期强度退化的影响。在此基础上，提出了评价强度发展的实用方法。(2)混凝土水化热温升分析。通过对试验得到的混凝土构件内部温度分布的检验表明，水化速率对温度存在依赖性，可用Arrhenius方程表示为13EA。开发了考虑这种依赖性的分析方法。(3)超高强混凝土拉拔试验的应用。使用特别改进的试验装置对超高强度混凝土进行了拉拔试验。推导出适用于混凝土强度w13EA全范围的强度预测公式。(4)建议的就地强度评估方法。结合强度法和温升分析，提出了一种确定配合比设计时目标强度的方法。A recommenden13EA\：应用强度发展理论和施工期混凝土拉拔试验，提出了现场强度评定的一种简便方法。