Test method to simulate the influence of the interface on the concrete carbonation process

A trial test method is introduced to form and magnify regular interface. Through researching on the carbonation of the magnifying interfacial transition zone (ITZ), the practical carbonation of the concrete can be simulated. Because the diffusion rate of CO₂ in the ITZ is several times greater than that in the bulk paste, the diffusion rate and direction of CO₂ will change and form a new carbonation front line. An interfacial effect zone caused by the ITZ will change the distribution of the complete carbonation zone and the partial carbonation zone. One of the important reasons for the formation of the partial carbonation zone was the existence of the interfacial effect zone. Consequently, the method mentioned in this paper provides a new way for researching on the microstructure of the cement based materials during the carbonation process.     

考虑界面过渡区及集料因素的水泥基材料碳化模型

集料和界面过渡区对水泥基材料抗碳化性能有显著影响。基于Fick第二定律,提出一种考虑集料和界面过渡区影响的CO₂扩散模型,模型中首次引入界面过渡区的扩散系数并给出相应参数的计算方法,并基于质量守恒定律给出CO₂反应模型,利用该模型研究荷载作用下C30和C50混凝土中CO₂的浓度分布。结果表明,考虑集料和界面过渡区影响能更准确地计算CO₂在水泥基材料中的扩散系数及碳化深度值。通过与文献中的试验数据进行比较,进一步验证了理论模型的可靠性。模型将集料和界面过渡区作为评价混凝土耐久性的重要因素,为钢筋混凝土结构的设计和寿命预测提供依据。