Abstract Alkali-Silica Reaction (ASR) is a particular type of chemical reaction in concrete, which produces cracking and overall expansion of the affected structural element due to the formation of expansive reaction products within the cracks. This paper develops the formulation of a coupled Chemo-Mechanical (C-M) Finite Element (FE) model for simulating ASR expansions in soda-lime glass concrete at the meso-scale. The model considers several C-M coupling mechanisms, including a reaction-expansion mechanism qualitatively proposed by the authors elsewhere on the basis of experimental results, which is introduced in order to reproduce the effect of compressive stresses on the development of ASR expansions. The model has the characteristic ingredient of using zero-thickness interface elements for modelling the C-M mechanisms leading to the propagation of cracks due to the formation of ASR products within them. This fact has required the development of: (i) a new FE formulation for diffusion-reaction processes occurring within discontinuities represented by interface elements, and (ii) a new mechanical constitutive law for interface elements, which is able to reproduce the propagation of a crack induced by the development of an internal pressure exerted by solid reaction products formed within it. In addition, the numerical implementation of the diffusion-reaction formulation has been advantageously performed with clear separation between the boundary-value or ‘structural’ governing equations (i.e. continuity and concentration gradient relations), and the ‘constitutive’ (i.e. chemical) equations. The model is illustrated with some application examples.

中文翻译：

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使用零厚度化学-机械界面元素的混凝土中碱-二氧化硅反应膨胀模型

摘要 碱硅反应（ASR）是混凝土中一种特殊的化学反应，由于在裂缝内形成膨胀反应产物，从而导致受影响结构元件的开裂和整体膨胀。本文开发了耦合化学-机械 (CM) 有限元 (FE) 模型的公式，用于在中尺度模拟钠钙玻璃混凝土中的 ASR 膨胀。该模型考虑了几种 CM 耦合机制，包括作者在其他地方根据实验结果定性提出的反应膨胀机制，引入该机制是为了重现压应力对 ASR 膨胀发展的影响。该模型的特征成分是使用零厚度界面元素对 CM 机制进行建模，该机制导致裂纹扩展，因为在其中形成 ASR 产品。这一事实需要发展：(i) 一种新的有限元公式，用于发生在由界面元素表示的不连续性内的扩散反应过程，以及 (ii) 一种新的界面元素机械本构定律，它能够重现由内部形成的固体反应产物施加的内部压力的发展引起的裂纹。此外，扩散反应公式的数值实现已经有利地在边界值或“结构”控制方程（即连续性和浓度梯度关系）之间明确分离，和“本构”（即化学）方程。该模型通过一些应用示例进行了说明。