硅锰渣-固硫灰复合辅助性胶凝材料水化机理研究

早期水化活性过低是限制冶炼渣在胶凝材料体系中大掺量应用的重要因素之一。利用固硫灰(CFBA)中的硫酸盐激发硅锰渣(SM)水化活性,并研究硅锰渣-固硫灰复合辅助性胶凝材料的水化过程及活性发展。结果表明:随着固硫灰掺量增加,胶砂流动度大幅下降,但其早期和后期活性得到有效提升;当固硫灰掺量为10%(质量分数)时,复合辅助性胶凝材料3 d、7 d和28 d活性指数分别达到61%、71%和95%,均高于单独使用硅锰渣体系(3 d、7 d和28 d活性指数分别为50%、53%和81%)。固硫灰的掺入激发了水泥和辅助性胶凝材料的早期水化,延缓了水化过程中钙矾石转变为单硫型水化硫铝酸钙(AFm),使得胶凝材料早期水化形成更多钙矾石。

Hydration Mechanism of Silicomanganese Slag-Circulating Fluidized Bed Combustion Ash Composite Supplementary Cementitious Materials

Lower early hydration activity is one of the important factors limiting the application of higher content smelting slag in the cementitious materials system. In this study, silicomanganese slag (SM) was activated by sulfate in circulating fluidized bed combustion ash (CFBA), and the hydration process and activity development of SM-CFBA composite supplementary cementitious materials were studied. Results show that the fluidity of mortars prepared by using SM-CFBA composite supplementary cementitious materials decreases significantly with the increase of CFBA. However, early and later activity of SM-CFBA composite supplementary cementitious materials are effectively improved with the increase of CFBA. When the content of CFBA is 10% (mass fraction) in SM-CFBA composite supplementary cementitious materials, 3 d, 7 d, and 28 d strength activity indexes of them reach 61%, 71%, and 95%, respectively, which is higher than those of SM (3 d, 7 d, and 28 d strength activity indexes are 50%, 53%, and 81%, respectively). The incorporation of CFBA stimulates the early hydration of cement and supplementary cementitious materials, and delays the transformation of ettringite into monosulfur-type hydrated calcium sulfoaluminate (AFm) during the hydration process, which allows early hydration of the cementitious materials to form more ettringite.