Effects of porosity on leaching of Ca from hardened ordinary Portland cement paste
Effects of porosity on leaching of Ca from hardened ordinary Portland cement paste
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DOI：
10.1016/j.cemconres.2004.06.034
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发表时间：
2005-09-01
影响因子：
11.4
通讯作者：
Nagasaki, S
中科院分区：
文献类型：
--
作者：
Haga, K;Sutou, S;Nagasaki, S
为了评价硬化水泥浆体中孔隙率对溶解现象的影响，制备了具有不同孔容的硬化普通波特兰水泥（OPC），然后将其在去离子水中浸出。结果表明，氢氧化钙的溶解对材料的体积密度和孔容有一定的影响。样品的孔隙体积越大，氢氧化钙溶解得越快。对固相的横截面进行的电子探针显微分析（EPMA）显示了“氢氧钙石（CH）溶解前沿”。随着淋滤时间的延长，CH溶解前沿向内部移动。此外，CH溶解前沿的运动由扩散模型描述，考虑了氢氧化钙的溶解。结果表明，浸出组分的迁移受扩散控制，硬化OPC的浸出组分主要为硅酸盐和C-S-H凝胶。氢氧化镁浸出过程中产生的大孔隙对浸出组分的扩散有重要影响。(c)2004 Elsevier Ltd.保留所有权利。
Aiming at evaluating the effects of porosity in hardened cement paste on dissolution phenomena, we prepared hardened ordinary Portland cement (OPC), with variation in pore volume, and then leached them in deionized water. It was found that the bulk density and pore volume were affected by the dissolution of portlandite. The larger the pore volume of the sample, the more rapidly portlandite is dissolved. An electron probe microanalysis (EPMA) performed on the cross-section of the solid phase showed the 'portlandite (CH) dissolution front'. As the leaching period became longer, the CH dissolution front shifted towards the inner part. In addition, the movement of the CH dissolution front was described by the diffusion model, with consideration of the dissolution of portlandite. It was concluded that the transport of leached constituents is diffusion controlled, and the major leached constituents of hardened OPC are portlandite and C-S-H gel. Large pore, which was generated associated with the leaching of portlandite, was considered significantly to affect the diffusion of leached constituents. (c) 2004 Elsevier Ltd. All rights reserved.