Impact of sample preparation on the specific surface area of synthetic ettringite

被引：89

作者：

Mantellato, Sara ^{[1
]}

Palacios, Marta ^{[1
]}

Flatt, Robert J. ^{[1
]}

机构：

[1] Swiss Fed Inst Technol, Inst Bldg Mat, Stefano Franscini Pl 3, CH-8093 Zurich, Switzerland

来源：

CEMENT AND CONCRETE RESEARCH | 2016年 / 86卷

关键词：

Thermal treatment; Surface area; X-ray diffraction; Ettringite; Solvent exchange; SOLID-SOLUTION; CEMENT; SUPERPLASTICIZERS; DIFFRACTION; STABILITY;

D O I：

10.1016/j.cemconres.2016.04.005

中图分类号：

TU [建筑科学];

学科分类号：

0813 ;

摘要：

The effect of sample preparation, including degassing conditions and method to stop cement hydration, on the specific surface area (SSA(BET)) of synthetic ettringite (AFt) was studied. Dehydration of AFt occurs even at moderate temperatures under N-2 flow (0% RH). However, partial dehydration associated to a loss of up to 12 water molecules does not imply a change in SSA(BET). A mild degassing 16 hat 40 degrees C under N-2 flow is suggested mainly to preserve the chemical composition and morphology of calcium sulfate carrier. At higher temperatures, ettringite dehydration involves a significant modification of its crystalline structure and increase of the SSA(BET). Typical protocols to stop cement hydration, solvent exchange and freeze-drying, lead to larger water removal from the AFt and crystallinity reduction, being significantly higher when the latter is applied. However, only freeze-drying leads to a moderate increase of the synthetic AFt SSA(BET). (C) 2015 Published by Elsevier Ltd.

引用

页码：20 / 28

页数：9

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