Effect of Isothermal Drying Process of Cement Paste, Mortar and Concrete on Compressive Strength

被引：0
|
作者：
Du X. [1 ]
Li Z. [1 ]
Han J. [1 ]
Zhang R. [1 ]
机构：
[1] College of Water Resources and Architectural Engineering, Northwest A & F University, Yangling, 712100, Shanxi
来源：
Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society | 2019年 / 47卷 / 05期
关键词：
Compressive strength; Concrete; Drying deformation; Isothermal drying; Microstructure;
D O I：
10.14062/j.issn.0454-5648.2019.05.08
中图分类号：
学科分类号：
摘要：
Effect of isothermal drying on the compressive strength of cement paste, mortar and concretewas investigated, and the mechanism in micro-scale was analyzed. The results show that isothermal drying has an effect on the compressive strength of cement-based materials, and the increase in compressive strength of concrete mainly is due to the strength improvement of cement paste. There is a logarithmic relationship between drying-strengthening effect and the mass fraction ofpaste. The drying deformation of cement paste, mortar and concrete all exhibit obvious characteristics of firstly expansion and then shrinkage. The drying process and deformation of concrete depend on the water removal and drying deformation of cement paste. The time required to the fully drying state, water-losing rate and drying deformation decrease with the decrease of mass fraction of cement paste. The porosity and average pore diameter of cement paste and mortar increase afterdrying. The increased porosity of cement paste is mainly attributed to the increase of pores with the diametersof less than 100 nm, and the increased porosity of mortar is attributed to the increase of pores with the diametersof 100-1000 nm. The hydration products of cement becomemoredenseafter drying, however, the bond between aggregates and paste weakens.The increased strengthof concrete after isothermal drying is the competition resultbetweenstrengthening effect due to the densification of hydration productsand weakening effect due to the porosity increasing and microcracks propagation. © 2019, Editorial Department of Journal of the Chinese Ceramic Society. All right reserved.
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页码：639 / 647
页数：8
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