Influence of key parameters on drying shrinkage of cementitious materials
- 作者：Bissonnette ; Benoî ; t ; Pierre ; Pascale ; Pigeon ; Michel
- 关键词：Cement paste ; Concrete ; Drying ; Humidity ; Shrinkage
- 刊名：Cement and Concrete Research
- 出版年：1999
- 期刊代码：12_00088846
- 类别：ms
- 出版时间：October, 1999
- 卷：29
- 期：10
- 页码：1655-1662
- 文件大小：239 K
摘要
Drying shrinkage can be a major cause of the deterioration of concrete structures. The contraction of the material is normally hindered by either internal or external restraints and tensile stresses are induced. These stresses may exceed the tensile strength and cause concrete to crack. The evaluation of the stress distribution in the material requires the knowledge of the “real” free shrinkage deformation. This paper presents the results of a study performed to evaluate this deformation and obtain a better understanding of the behavior of concrete under drying conditions. Shrinkage tests were carried out on cement pastes, mortars, and concretes. The influences of different key parameters were evaluated: relative humidity, specimen size, water/cement ratio, and paste volume. The results indicate that between 48 and 100%relative humidity, the shrinkage of cement paste is approximately inversely proportional to relative humidity. Results also show that the ultimate shrinkage of pastes and mortars measured on 50 × 50 × 400-mm specimens does not differ much from the “real” shrinkage measured on 4 × 8 × 32-mm specimens. Thus, for the specimen dimensions investigated in this study, the existence of a humidity gradient did not affect to a large extent the ultimate shrinkage strain. The influence of the water/cement ratio, within the range investigated (0.35–0.50), was found to be relatively small. Conversely, paste volume was observed to have a very strong influence.