Abstract

The results of long-term and accelerated tests of cement–sand mortars with a reactive aggregate and additives Al₂(SO₄)₃ and Fe₂(SO₄)₃, carried out under the conditions of the corresponding standardized techniques, indicate that these additives suppress the development of destructive expansion deformations of mortars and concretes caused by alkali-silica reaction. In all samples of cement–sand mortars, after accelerated and long-term tests, destructive changes occurring with particles of reactive aggregate were noted. Ettringite was found in samples after long-term tests (its content is higher in samples with additives of aluminum and iron sulfates), whereas in samples subjected to accelerated tests in NaOH solution, ettringite rapidly decomposes with the formation of a hydrogarnet phase. The results of an energy dispersive microanalysis of an alkali-silicate hydrogel formed as a result of an alkali-silica reaction do not allow explaining the ability of aluminum and iron sulfates to suppress expansion deformations by their influence on the chemical composition of the hydrogel and, accordingly, on its destructive properties. It can be assumed that the presence in the samples of other phases (ettringite and hydrogarnet phase), the formation of which is promoted by additives, can have a restraining effect on the dynamics of the development of destructive expansion deformations.

中文翻译：

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碱性-二氧化硅反应的测试条件下，含无碱促进剂的水泥砂浆

摘要

使用活性骨料和添加剂Al ₂（SO ₄）₃和Fe ₂（SO ₄）₃的水泥砂浆的长期和加速试验结果在相应的标准化技术条件下进行的试验表明，这些添加剂抑制了由碱-二氧化硅反应引起的砂浆和混凝土破坏性膨胀变形的发展。在所有水泥沙浆样品中，经过加速和长期测试后，发现反应性骨料颗粒发生破坏性变化。长期测试后的样品中发现了钙矾石（在含有铝和硫酸铁添加剂的样品中其含量较高），而在NaOH溶液中进行加速测试的样品中，钙矾石迅速分解，形成水石榴石相。由于碱-二氧化硅反应而形成的碱-硅酸盐水凝胶的能量分散微分析结果无法解释铝和硫酸铁通过其对水凝胶化学成分的影响而抑制膨胀变形的能力，并且因此，其破坏性。可以假设样品中存在其他相（钙矾石相和水石榴石相），其形成是由添加剂促进的，可以抑制破坏性膨胀变形发展的动力学。