海水对不同矿物组成的铝酸盐水泥水化的影响

Effect of Seawater on Hydration of Calcium Aluminate Cement with Different Mineral Compositions

铝酸盐水泥(CAC)具有优良的抗海水侵蚀性能,为进一步开发其在海洋环境中的应用前景,研究了海水拌合对不同铝酸一钙/二铝酸一钙(CA/CA2)比例的CAC水化的影响。结果表明:水化早期,海水延缓了CAC水化,而且CA/CA2比例越低,延缓作用越显著;水化后期,海水促进了CAC水化,使得浆体中水化铝酸一钙(CAH10)生成量明显增加、孔结构优化,强度较自来水拌合时大幅提升,且CA/CA2比例越低,提升效果越显著。但与自来水相比,海水拌合时CAC后期强度倒缩程度更明显。无论自来水还是海水拌合,CAC主要水化产物都是CAH10,氯离子主要以物理吸附方式结合;所涉龄期内未发现与硫酸盐和镁离子侵蚀相关的水化产物。

Calcium aluminate cement(CAC) has a superior resistance to seawater erosion. In order to further develop the application potential of CAC in marine environment, the effect of seawater on the hydration of CAC with different calcium monoaluminate/calcium dialuminate(CA/CA2) ratios was investigated. The results show that in the early hydration stage, seawater retards the hydration of CAC, and the lower the CA/CA2 ratio is, the more significant the retarding would be. In the late hydration stage, seawater promotes the hydration of CAC, and the amount of monocalcium aluminate decahydrate(CAH10) in the paste increases and the pore structure optimizes, resulting in a prominent increase in the CAC strength, compared to that mixed with tap water. Moreover, a lower CA/CA2 ratio leads to a more improvement of the CAC strength. However, compared to tap water, the compressive strength of CAC strength decreases in the late stage when the CAC is mixed with seawater. Regardless of mixing with tap water or seawater, CAH10 is the main hydration product of CAC, and chloride ions are mainly bound by the physical adsorption. No hydration products related to sulfate and magnesium attack appear.