海洋环境下混凝土的碳化与钙的溶出

Carbonation and Calcium Leaching in Concrete under Marine Environment

从暴露26 a和21 a的实际混凝土工程中钻取了一批直径为100 mm的混凝土芯样,利用干磨技术和化学分析方法测量了其Cl-,CaCO3和Ca(OH)2含量.结果表明,在潮湿环境下混凝土碳化进展缓慢,混凝土碳化深度最终趋于一个极限值.对比CaCO3和Ca(OH)2的含量,发现与海水长期接触的混凝土存在Ca(OH)2的溶出和C-S-H的进一步脱钙,这会加剧Cl-对其的侵蚀作用.当存在Ca(OH)2的溶出时,以CaCO3含量来评价混凝土碳化的方法将变得不可靠.

Concrete core specimens were taken onsite from concrete construction after 26 a and 21 a exposure respectively. The contents of Cl^- , CaCO3 and Ca（OH）2 in the cores were determined by using the dry grinding technique and chemical analysis. Results show that the carbonation is low in humid environment and approaches a limit value. By comparing the content of CaCO3 and Ca（OH）2, it is found that in concrete in long-term contact with sea water the leaching of Ca（OH）2 and a progressive decalcification of C-S-H have happened, and this has a detrimental influence on Cl^- corrosive effect. It is not reliable by evaluating carbonation with content of CaCO3 on condition that Ca（OH）2 leaching happens.