Estimation of Defecs in Concrete in Early Age by Using Acoustic Emission Method

利用声发射法估算混凝土早期缺陷

• 批准号: 08650538
• 负责人: YAMURA Kiyoshi
• 金额: $ 1.41万
• 依托单位: Setsunan University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650538/
• 关键词: Acoustic emission; Defects in concrete; Drying shrinkage; Crack; Flowing concrete; 乾燥収縮1; 熟応力

In this study, defects in concrete causing in early age due to drying shrinkage, and poor casying and thermal stress were investigated and estimated by acoustic emission metod.Model specimens varying materials, mix proportions and the rate of restriction by reinforced bar were tested during 28days after casting. AE count rate shrinkage strain, were measured continuously during the test period. And the results were compared with parameters such as strengths and Young's modulus. From the results, AE count rate became large acording to that the tensile stress causing in concrete specimens became large. And the correlation between AE count rate and the development of defects in concrete in early stage was clearly obseved.At the same time, Same tests for flowing concrete were carried out. AE count rate of flowing concrete was evidently small compared to that of normal concrete. This shows that flowing concrete have very good compativility and the defects in concrete developing in early stage such as large air void are rare. Tllis was confirmed from the air voids obsevation test by linear traverse method.

本文采用声发射法对混凝土早期因干燥收缩、浇筑不良和温度应力等引起的缺陷进行了研究和评价，并对不同材料、配合比和钢筋约束率的模型试件进行了浇筑后28天的试验。在试验期间连续测量AE计数率和收缩应变。并与强度、弹性模量等参数进行了比较。结果表明，混凝土试件中产生的拉应力越大，声发射计数率越大。同时，对流动混凝土进行了同样的试验。流态混凝土的声发射计数率明显小于普通混凝土。这说明流态混凝土具有很好的密实性，混凝土早期发展过程中的大空隙等缺陷很少出现。通过线性导线法的空隙率观察试验证实了这一点。

项目成果

K.Yamura: "Experimental Study on Kaizer Effect on Deteriolation of Concrete" Proc. of JCI. Vol. 18, No. 1. 1263-1268 (1996)

K.Yamura：“Kaizer 效应对混凝土劣化的实验研究”Proc。

矢村 潔: "コンクリートの劣化とカイザー効果に関する実験的研究" コンクリート工学年次論文報告集. Vol.18,No.1. 1263-1268 (1996)

Kiyoshi Yamura：“混凝土劣化和凯泽效应的实验研究”混凝土工程年论文集第18卷，第1263-1268期（1996年）。

矢村 潔: "コンクリートの劣化とカイザー効果に関する実験的研究" コンクリート工学年次論文報告集. Vol.18 No.1. 1263-1268 (1996)

Kiyoshi Yamura：“混凝土劣化和凯泽效应的实验研究”混凝土工程年论文集第18卷第1263-1268号（1996）。