External Sulphate Attack on Alkali-Activated Slag and Slag/Fly Ash Concrete
External Sulphate Attack on Alkali-Activated Slag and Slag/Fly Ash Concrete
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DOI：
10.3390/buildings12020094
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发表时间：
2022-02-01
期刊：
影响因子：
3.8
通讯作者：
Nanukuttan, Sreejith
中科院分区：
文献类型：
--
作者：
Bondar, Dali;Nanukuttan, Sreejith
两种类型的碱激发材料（AAM）混凝土暴露于各种硫酸盐轴承溶液超过两年。研究了混凝土试样的物理变化和暴露液体中的化学变化，试图了解硫酸盐侵蚀如何发生在此类粘合剂中，以及混合变量在提供抵抗此类侵蚀方面所起的作用。碱矿渣混凝土（AASC）的配合比变量包括水胶比、碱的百分比和SiO2/Na 2 O比（二氧化硅模量，Ms）;碱矿渣/粉煤灰（AA-S/F）混凝土的配合比变量包括矿渣/粉煤灰比和SiO2/Na 2 O比。暴露溶液包括水、硫酸镁（5%）、硫酸钠（5%）、硫酸钙（0.2%）和两种浓度的硫酸溶液（pH 3和pH 1）。所研究的物理变化为长度和质量变化、视觉外观和抗压强度变化。分析暴露液体的pH值和离子组成的变化。研究结果表明，AA-S/F共混物在硫酸盐环境中的性能优于AASC，基于强度和长度的变化。暴露于水导致最膨胀/收缩，在所有的混合研究。提出了一个预测AAS和AA-S/F混凝土抗压强度随质量增加而变化的经验模型。此外，一个简单的性能标准，提出了混合物在硫酸盐环境中的质量增益的基础上。
Two types of alkali-activated material (AAM) concretes were exposed to various sulphate bearing-solutions for over two years. Physical changes to the concrete specimen and chemical changes in the exposure liquid were studied in an attempt to understand how sulphate attack occurs in such binders and the role the mix variables play in offering resistance against such attack. The mix variables of alkali-activated slag concrete (AASC) included water-to-binder ratio, percentage of alkali, and the SiO2/Na2O ratio (silica modulus, Ms); for alkali-activated slag/fly ash (AA-S/F) concrete, the mix variables included slag/fly ash ratio and the SiO2/Na2O ratio. The exposure solutions included water, magnesium sulphate (5%), sodium sulphate (5%), calcium sulphate (0.2%), and two concentrations of sulphuric acid solutions, pH 3 and pH 1. The physical changes studied were length and mass change, visual appearance, and change in compressive strength. The exposure liquids were analysed for change in pH and ionic composition. Findings show that the AA-S/F blend performs better than AASC in sulphate environments, based on strength and change in length. Exposure to water resulted in the most expansion/shrinkage in all mixes studied. An empirical model was proposed for predicting the change in compressive strength for AAS&AA-S/F concretes based on mass gain. Further, a simple performance criterion was put forward for mixes in sulphate environments based on mass gain.