The effect of ionic contaminants on the early-age properties of alkali-activated fly ash-based cements
The effect of ionic contaminants on the early-age properties of alkali-activated fly ash-based cements
复制标题
DOI：
10.1016/s0008-8846(01)00724-4
复制
发表时间：
2002-04-01
影响因子：
11.4
通讯作者：
van Deventer, JSJ
中科院分区：
文献类型：
--
作者：
Lee, WKW;van Deventer, JSJ
碱激发粉煤灰基水泥是利用粉煤灰作为其主要固体原料的混凝土粘合剂。使用浓缩的硅酸盐和氢氧化物溶液活化固体颗粒，以生产高强度产品。由于溶液的高碱性性质，反应性物质从固体和溶液中的沉淀以非常快的速率进行。这使得凝固时间短，这取决于实际情况可能是有利的或不利的。本文研究了无机盐对早期水泥浆体的凝结和流变特性的影响。对硬化产物进行了抗压强度、傅里叶变换红外光谱（FTIR）和X射线衍射分析。结果发现，钙（Ca）和镁（Mg）盐缩短了凝固时间，通过提供在初始糊状溶液中的异质成核中心。钾盐只延缓水泥的凝固，因为在初始溶液中硅酸钠的用量较少。受控的离子污染可用于提高产品的早期强度。然而，其长期影响仍有待确定。(C)2002爱思唯尔科技有限公司版权所有。
Alkali-activated fly ash-based cements are concrete binders that utilise fly ash as their major solid raw material. The solid particles are activated using concentrated silicate and hydroxide solution to produce high-strength products. Due to the highly alkaline nature of the solution, precipitation of the reactive species, both from the solids and from the solution, proceeds at a very fast rate. This renders short setting Times, which can be advantageous or disadvantageous depending on the practical situation. The present work examines the effects of inorganic salt addition towards the setting and rheological characteristics of the early pastes. Compressive strength, Fourier transform infrared spectroscopy (FTIR) and X-ray diffractograms were collected to examine the hardened products. It was found that calcium (Ca) and magnesium (Mg) salts shortened the setting time by providing heterogeneous nucleation centers in the initial paste solution. Potassium salts retarded setting only to the cements, which used less sodium silicate in the initial solution for activation. Managed ionic contamination can be used to increase the product early strength. However, its long term effects still need to be identified. (C) 2002 Elsevier Science Ltd. All rights reserved.