Abstract Carbonation of cementitious materials induced by their interaction with atmospheric CO2 is one of the main degradation mechanisms threatening their durability. In this study, a novel thermodynamic model to predict the phase evolution of alkali-activated slags exposed to an accelerated carbonation environment is presented. This model predicts the phase assemblages of carbonated alkali-activated slag cements, as a function of CO2 uptake under 1 v/v % CO2 conditions, considering the bulk slag chemistry and activators used. The changes taking place during the carbonation process regarding the physicochemical properties of the main binding gel, an alkali calcium aluminosilicate hydrate (C-(N)-A-S-H), the secondary reaction products Ca Al and Mg Al layered double hydroxides, and amorphous aluminosilicate gels, were simulated and discussed. The predictions of the thermodynamic model are in good agreement with experimental data retrieved from the literature, demonstrating that this is a valuable tool for predicting long-term performance of alkali-activated slag cements.

中文翻译：

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暴露于二氧化碳的碱活化矿渣水泥中相演变的热力学模型

摘要 胶结材料与大气 CO2 相互作用引起的碳化是威胁其耐久性的主要降解机制之一。在这项研究中，提出了一种新的热力学模型来预测暴露于加速碳化环境中的碱活化炉渣的相演变。该模型预测碳酸碱活化矿渣水泥的相组合，作为 1 v/v % CO2 条件下 CO2 吸收的函数，考虑到所使用的大量矿渣化学和活化剂。在碳酸化过程中发生的关于主要粘合凝胶、碱性铝硅酸钙水合物 (C-(N)-ASH)、次级反应产物 Ca Al 和 Mg Al 层状双氢氧化物以及无定形铝硅酸盐凝胶的物理化学性质发生的变化，进行了模拟和讨论。