粉煤灰在硅酸盐水泥浆体中的化学反应

摘要

定量测试1～360 d纯硅酸盐水泥及掺粉煤灰水泥浆体中胶凝组分的反应程度、生成的氢氧化钙(CH)量及化学结合水(Wn)量;确定单位质量水泥及粉煤灰完全反应生成(或吸收)的CH或Wn量,并以此验证粉煤灰化学反应模型的精确性.结果表明.1g水泥完全水化生成0.242 5 g的CH和0.235 1 g的Wn,1 g粉煤灰完全反应吸收0.508 9 g的CH和0.183 9 g的Wn,试验结果与现有的粉煤灰化学反应模型计算值差别较大;经修正,获得计算值与试验值较吻合的粉煤灰化学反应模型,该模型更能真实反映粉煤灰在水泥浆体中的化学反应.%Cement hydration degree,fly ash reaction degree,portlandite(CH) content and chemically combined water(Wn) content in both pure Portland cement paste and fly ash blended Portland cement paste aged from 1 to 360 days were determined quantitatively.Then,the amounts of CH and Wn generated(or absorbed) by complete hydration of unit mass cement and fly ash were investigated respectively.Finally,the accuracy of chemical reaction model of fly ash in cement paste was discussed.The results show that 1 g cement combines 0.235 1 g Wn and generate 0.242 5 g CH while 1 g fly ash reacts with 0.508 9 g CH and generates 0.183 9 g Wn.The theoretical data calculated by existing reaction model and experimental data show significant difference.After reaction model amendment,the calculated data are consistent with the experimental data well,indicating that the amended reaction model truthfully reveals chemical reaction of fly ash in cement paste.