C-S-H晶种与硫酸铝作用下PC-CSA的凝结硬化性能

Setting and Hardening Performance of PC-CSA under C-S-H Seed and Aluminum Sulfate

摘要:

利用凝结时间、抗压强度等测试，系统评价了水化硅酸钙（C-S-H）晶种与硫酸铝（AS）对硅酸盐-硫铝酸盐复合胶凝体系（PC-CSA）凝结硬化性能的影响，并通过水化进程、水化产物和微观结构分析探究其内在作用机理.结果表明：C-S-H晶种与AS均能显著缩短PC-CSA的凝结时间；复掺C-S-H晶种与AS显著促进了PC-CSA中硅相矿物的水化，提高了微观结构的致密性，提升了PC-CSA的抗压强度；当单掺AS时，PC-CSA中水化产物C-S-H的成核与长大过程均受抑制，而C-S-H晶种的加入通过提供成核位点，减缓了对水化产物C-S-H成核过程的抑制效果，促进了硅相矿物的反应，有助于解决喷射混凝土速凝与早强不协调的问题.

Abstract:

Through tests of setting time and compressive strength， the effect of calcium silicate hydrated（C-S-H） seed and aluminum sulfate （AS） on the setting and hardening performance of ordinary Portland cement-calcium sulfoaluminate cement （PC-CSA） was systematically investigated. Moreover， the mechanism was revealed with the combined techniques of hydration process， hydration product and microstructure analysis. The results show that both C-S-H seed and AS significantly shorten the setting time of PC-CSA. The combined addition of C-S-H seed and AS significantly promotes the silicate phase reaction of PC-CSA and densifies the microstructure to enhance the compressive strength of PC-CSA. When AS is doped alone， the nucleation and growth processes of hydration product C-S-H in PC-CSA are inhibited. However， the addition of C-S-H seeds mitigates the inhibition effect on the nucleation process of hydration product C-S-H by providing nucleation sites， thereby promoting the silicate phase reaction.Hence， these results address the imbalance between rapid setting and enhanced early strength of the shotcrete.