Effect of Heat Treatment on Pore Structure of Polymer Modified Hardened Cement Pastes

被引：0

作者：

Zhang C. ^{[1
]}

Kong X. ^{[1
]}

机构：

[1] Institute of Building Materials, Department of Civil Engineering, Tsinghua University, Beijing

来源：

Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society | 2019年 / 47卷 / 02期

关键词：

Film-formation; Hardened cement paste; Heat treatment; Polymer; Pore structure;

D O I：

10.14062/j.issn.0454-5648.2019.02.06

中图分类号：

学科分类号：

摘要：

Pore structure of hardened cement paste (HCP) is a decisive factor for the durability of concrete as well as one of the critical factors for mechanical strength, shrinkage and cracking of cementitious materials. Polymer latex is usually used as an additive of cementitious materials to improve their flexural strength, tension strength and toughness. Temperature variation was supposed to affect the pore structure of polymer modified hardened cement paste by changing the state of the polymer phase. In this paper, the influence of heat treatment on the pore structure of polymer modified hardened cement paste was investigated by nitrogen adsorption, X-ray diffraction and scanning electron microscopy. The addition of non-film-forming polymer (L2) increases the pore volume of HCP, while the addition of film-forming polymer (L1) decreases the pore volume of HCP after curing at normal temperature. Also, the addition of film-forming polymer (L1) depresses the conversion of ettringite (AFt) to calcium monosulfoaluminate hydrate (AFm) during cement hydration, so that AFt phase appears in the L1 modified HCP at 28 d and 90 d, whereas it is absent in the blank HCP and the L2 modified HCP. Heat treatments at 65℃and 90℃lead to the water loss of HCP and partly decomposition of hydration products, resulting in the increase of total pore volume of the blank HCP and the film-forming polymer modified HCP (PL1). For non-film-forming polymer modified HCP, heat treatment causes the fusion of polymer particles and film formation, resulting in a decrease of the total pore volume. © 2019, Editorial Department of Journal of the Chinese Ceramic Society. All right reserved.

引用

页码：192 / 200

页数：8

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