混凝土碱-骨料反应长期膨胀变形预测模型研究进展

A review of long-term expansion prediction model of concrete suffering alkali-aggregate reaction

  • 摘要: 碱-骨料反应被称为混凝土的“癌症”,是影响混凝土寿命的重要因素。对于已经使用活性骨料的混凝土结构,如何预测碱-骨料反应引起的混凝土长期变形,并合理评价结构的整体安全性,是工程密切关心的问题。回顾了混凝土碱-骨料反应长期变形预测模型的研究进展,将现有模型归为宏观膨胀的数学拟合模型、结构宏观变形的唯象学模型、基于骨料膨胀的模型、考虑碱-硅酸反应(ASR)凝胶的模型、考虑物质迁移的模型等五大类,并分析了各种模型的优缺点和适用范围。认为ASR长期膨胀变形预测模型需重点考虑碱离子向骨料内部的扩散、SiO2的溶解及凝胶的组成,且需根据岩相分析来选择 “反应环”模型或“凝胶袋”模型。

     

    Abstract: Alkali-aggregate reaction is called the “cancer” of concrete and is one of the important factors affecting the durability of concrete. For the concrete structure with active aggregate, how to predict the long-term deformation of concrete caused by alkali-aggregate reaction and reasonably evaluate the overall safety of the structure is a problem of vital concern to the project. In this paper, the research progress of long term deformation prediction models for alkali-aggregate reaction of concrete is reviewed. The existing models are classified into 5 categories: mathematical modeling of macroscopic expansion, phenomenological model of macroscopical deformation of structures, models based on aggregate expansion, models based on ASR gel and models based on material migration. The advantages, disadvantages and application scope of various models are analyzed. It is proposed that the prediction model of ASR long-term expansion needs to consider the effect of alkali ion diffusion into the aggregate, SiO2 dissolution and the composition of ASR gel, and the reaction ring model or gel pocket model should be selected according to the petrographic analysis.

     

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