矿渣粉、高钙灰及其改性材料对水泥早期水化进程的影响

通过水泥化学收缩和水化热测试方法研究了矿渣粉、高钙灰和脱硫石膏、煅烧脱硫石膏、硫酸钠等改性材料对水泥浆体早期水化进程的影响,同时与不同试样的早期强度进行对比分析.50%的矿渣粉和高钙灰替代水泥后显著降低塑性阶段的化学收缩和早期强度,但对硬化后的化学收缩影响不大,矿渣粉与高钙灰按照适当比例复合对降低塑性阶段化学收缩的作用更明显,有利于降低塑性开裂;脱硫石膏和元明粉对早期化学收缩影响不大.矿渣粉、高钙灰替代50%水泥后明显降低第2放热峰并增加1个第3放热峰,纯矿渣粉的第3放热峰较高,复掺20%高钙灰后第3放热峰降低并且出现时间延后,复掺30%高钙灰使第2放热峰也降低,水化热显著减少;脱硫石膏或煅烧脱硫石膏延缓水化反应进程而对总体反应程度影响不大;水化热实验结果显示硫酸钠促进早期水化反应的作用明显.结果表明:采用20%高钙灰替代矿渣粉对早期水化程度和初始结构建立影响不大,脱硫石膏或煅烧脱硫石膏作激发材料能够分散早期的集中放热而对总体水化进程影响不大;水化热对水化过程的反映比化学收缩更清晰和更准确.

EFFECTS OF SLAG, HIGH-CALCIUM FLY ASH AND ACTIVATING MATERIALS ON EARLY HYDRATION DEGREES OF CEMENTS

The effects of mineral materials, grinded blast furnace slag (S), high-calcium fly ash (HF), desulfurized gypsum (DG),calcined desulfurized gypsum (CG) and sodium sulfate (NS) on the hydration degree of cement pastes are researched according totesting results of the chemical shrinkage, the hydration heat and the compressive strength. When 50% cement is replaced by the samemass of S or HF, the chemical shrinkage during the plastic period and early strength decrease. For hardened pastes, S or HF dose notaffects the chemical shrinkage much. Blending S with HF can decrease the chemical shrinkage significantly and may prevent plasticcrazing. When 50% cement is replaced by S or HF, a new (third) hydrating heat peak appears and the second one falls. The third hy-drating heat peak of the sample with ground granulated blast furnace slag (GBFS) is the highest, and that of the sample with 80% Sand 20% HF appears later and is lower., and the second hydrating heat peak of the sample with 70% S and 30% HF increases. DO orcalcined DG (CG) prolongs the early age hydration and affects the whole hydration degree somewhat. The results for hydrating heatshow that NS accelerates early hydration significantly. When 20% of S is replaced by I-IF, the early hydration degree and initial structureare only slightly affected unless the dosage of HF is quite high. Useing DG or CG as active material allows the separation of early hy-drating heat and affects the whole hydration degree little. The effect of NS on early shrinkage is little, but affects early hydrating heatobviously. The testing result of hydration heat can reflect the hydration degrees more clearly and exactly than that of chemical shrinkage.