混凝土碳化研究与进展(2)——碳化速度的影响因素及碳化对混凝土品质的影响

Review of carbonation in reinforced concrete(Ⅱ): Factors influencing carbonation rate of concrete and carbonation effect on concrete structure

混凝土碳化速度决定于孔结构和CO2气体与孔溶液成分的反应性。孔结构决定CO2和H2O的渗透能力,孔隙不含水时CO2的扩散能力强,而无法完成CO2与水化产物的碳化反应,因此混凝土孔结构是影响碳化速度的主要因素。混凝土中的碱含量、NaCl含量及孔隙水的迁移等对碳化速度的影响也非常大。碳化减少碳化区和未碳化区孔径和孔隙率的同时也影响混凝土质量、强度和碱度等其它性能。

Carbonation rate depends on the pore structure and reactivity between CO2 gas and pore solution composition. Pore solution. Pore structure of mortar is a key factor which determines the progress of carbonation by affecting diffusivity of CO2 and permeability of water. The reaction between CO2 and hydration products may not occur without the presence of water. Therefore, the pore structure of mortar becomes the controlling factor of carbonation rate. Besides, the carbonation rate of mortar in concrete is strongly related to the alkali contents, sodium chloride contents and migration of pore solution. Carbonation reduces the pore size distribution and porosity of carbonated and non - carbonated part, and affects the concrete weight, strength, alkalinity et al.