煤气化渣微粉胶凝体系水化机理研究

Research on Hydration Mechanism of Cementitious System of Coal Gasification Slag Micropowder

通过胶砂强度、水化热及扫描电镜(SEM),对纯水泥、掺粉煤灰、掺煤气化渣微粉三种胶凝体系的水化机理进行研究,结果表明:在同水胶比、同掺量的条件下,掺煤气化渣微粉组胶砂跳桌流动度较小,早期强度高于粉煤灰组,后期强度低于粉煤灰组;掺煤气化渣微粉组的水化热温度与放热速率要高于粉煤灰组;对三种胶凝体系水化产物的微观形貌分析发现纯水泥组与粉煤灰组的水化产物相似,而掺煤气化渣微粉组3 d水化产物生成了大量结晶度较低的纤维状水化硅酸钙凝胶,28 d水化产物由结晶度较低的纤维状水化硅酸钙凝胶转化为结晶度较高的类似于硬硅钙石的针状晶体,使得胶砂强度随之增强。

Through cementing strength,hydration heat and scanning electron microscope(SEM),three kinds of cementitious cement,fly ash and micropowder of coal gasification slag are mixed.The hydration mechanism of the system is studied.The results show that with the same W/B and the same amount of mixing,the flow degree of the skip table with coal gasification slag powder group is slightly higher than that of the fly ash group.The early strength is higher than that of the fly ash group,and the later strength is lower than that of the fly ash group;the hydration heat temperature and exothermic rate of the coal gasification slag micro powder group are higher than that of the fly ash group.The microscopic morphology of the hydration products of the three cementing systems show that the hydration products of the pure cement group and the fly ash group are similar,a large amount of fibrous hydrated calcium silicate gel is produced by the 3 d hydrated product mixed with coal gasification slag.The hydration product of 28 d is converted from a low crystalline calcium silicate gel into a needle like crystal with a higher degree of crystallinity similar to stony calcareous stone which increases the strength of the mortar.