Impact of zeta potential of early cement hydration phases on superplasticizer adsorption

被引：582

作者：

Plank, Johann ^{[1
]}

Hirsch, Christian ^{[1
]}

机构：

[1] Tech Univ Munich, Inst Organ Chem, D-85747 Garching, Germany

来源：

CEMENT AND CONCRETE RESEARCH | 2007年 / 37卷 / 04期

关键词：

adsorption; admixture; ettringite; monosulfate; zeta potential;

D O I：

10.1016/j.cemconres.2007.01.007

中图分类号：

TU [建筑科学];

学科分类号：

0813 ;

摘要：

The zeta potential of early hydration products of cement was found to be a key factor for superplasticizer adsorption. A highly positive zeta potential results in a strong superplasticizer adsorption whereas a negative zeta potential does not allow adsorption. Synthetic ettringite precipitated from solution shows a highly positive zeta potential, hence it adsorbs great amounts of negatively charged superplasticizer. Monosulfate (AF(m)) has a less positive zeta potential. Therefore, it adsorbs smaller amounts of superplasticizers. For syngenite, portlandite and gypsum, the zeta potential is around zero or negative. These phases do not adsorb superplasticizers. Consequently, a hydrating cement grain is best represented by a mosaic structure, with superplasticizer molecules mainly adsorbed on ettringite and some on monosulfate and C-S-H nucleated at surface. (c) 2007 Elsevier Ltd. All rights reserved.

引用

页码：537 / 542

页数：6

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