作　　者： (胡晓鹏）; (孙广帅）; (张成中）; (张永利）;

机构地区： 西安建筑科技大学土木工程学院,陕西西安710055

出　　处： 《西安建筑科技大学学报（自然科学版）》 2017年第4期492-496,共5页

摘　　要： 通过自然暴露条件下的混凝土早期碳化试验,研究了不同养护时间混凝土早期碳化深度、孔溶液pH值随龄期的变化规律,分析了混凝土早期碳化过程中物质成分的变化规律,探讨了混凝土早期碳化对渗气性和渗水性的影响规律.研究表明:混凝土的碳化深度在浇筑后的90d内发展极快,混凝土龄期为90~180d时早期碳化深度发展较慢且混凝土不同程度出现回碱现象,混凝土龄期达到180d后碳化深度继续发展;从试块表面向内部方向,pH值快速增大,pH值增大速度随着试件深度的增加逐渐变缓,最终pH值趋于定值;沿砂浆侧面向内部延伸,CaCO3含量逐渐减少并趋于定值而Ca(OH)2含量逐渐增大并趋于定值;随着养护时间的延长,混凝土的早期碳化发展速度减慢,各层混凝土孔溶液中的pH值逐渐增大且增大量随着试件深度的增加而减小,混凝土的渗气性先减弱后增强,混凝土的渗水性先微弱增强后明显减弱. Through early carbonation test of concrete in conditions of natural exposure, the changes laws of early carbonation depth and pore solution pH value with concrete age under different curing time were studied, the change laws of material composition in process of early concrete carbonation were analyzed, and the influence laws of early concrete carbonation on gas permeability and water permeability were discussed. The research results show that the carbonation depth develops fast within concrete age of 90 d after concrete casting time, the carbonation depth develops slow and the alkali phenomenon occurs when the concrete age changes from 90 d to 180 d, the carbonation depth continues to develop after the concrete age reaches 180d. The pH value increases rapidly from surface to internal direction of the specimen, the increase rate of the pH value becomes slow gradually with the increasing of specimen depth and the pH value reaching a certain value in the deep of specimen. Extending along the side of mortar specimen, the CaCO3 content gradually decreases and tends to reach a certain value, while the Ca （OH）2 content gradually increases and tends to reach a certain value. With the increase of curing time, the development speed of early carbonation depth slows down; the pH values of pore solution in each layer increase gradually; the growth amount of the pore solution pH value decreases with increase of the specimen depth~ the gas permeability of concrete decreases first and then increases; and the water permeability of the concrete increases slightly and then decreases obviously.

关 键 词： 混凝土 早期碳化深度 值测试 物质成分分析 渗透性