Permeability modeling of self-healing due to calcium carbonate precipitation in cement-based materials with mineral additives

基于碳酸钙沉淀掺矿物外加剂水泥基材料的自愈合渗透性模型（英文）

The permeability modeling of self-healing due to calcium carbonate precipitation in cement-based materials with mineral additives was studied in this work. The parameters of calcium carbonate precipitation during self-healing were simulated. A permeability modeling of self-healing, combined with numerical simulation of calcium carbonate formation, was proposed based on the modified Poiseuille flow model. Moreover, the percentage of calcium carbonate in healing products was measured by TG-DTA. The simulated results show that self-healing can be dramatically promoted with the increase of pH and Ca2+ concentration. The calculated result of permeability is consistent with that measured for cracks appearing in middle or later stages of self-healing, it indicates that this model can be used to predict the self-healing rate to some extent. In addition, TG-DTA results show that the percentage of calcium carbonate in healing products is higher for mortar with only chemical expansion additives or cracks appearing in the later stage, which can more accurately predict the self-healing rate for the model.

本文基于碳酸钙沉淀愈合裂缝机理,研究了掺矿物外加剂的水泥基材料裂缝自愈合渗透性模型。模拟了自愈合过程中影响碳酸钙沉淀的主要参数,同时结合改性的泊肃叶渗流模型,提出了自愈合渗透性模型,最后使用热重分析测试了愈合产物中碳酸钙所占的比例。结果表明,在一定范围内,自愈合效果随着裂缝溶液中pH和钙离子浓度的增加而显著提升。中期或后期开裂的砂浆,其自愈合渗透性的计算结果与测试结果一致,这说明在某种程度上自愈合渗透性模型能够预测裂缝的自愈合速率。此外,热重分析结果表明,单掺膨胀剂或晚龄期开裂砂浆的愈合产物中含有更高比例的碳酸钙,有利于模型更准确地预测裂缝的自愈合速率。