葡聚糖分子质量对水泥水化的影响研究

The study on the effect of molecular weight of dextran on the hydration of cement

通过等温量热仪及半绝热的胶砂直接法研究了相对分子质量分别为5000、10000、20000和40000的葡聚糖对水泥净浆和胶砂水化放热的影响。结果显示,不同分子质量的葡聚糖均具有抑制水泥水化历程的作用;随葡聚糖分子质量增大,水泥水化诱导期缩短;水泥净浆水化放热速率峰值和胶砂水化温峰值随葡聚糖分子质量的增大而增大;0.3%掺量下,相对分子质量分别为5000、10000、20000和40000的葡聚糖水泥净浆在20℃恒温条件下的水化放热速率峰值较未掺葡聚糖的基准样降幅分别为55.8%、35.4%、48.9%和25.4%,水泥胶砂温峰分别降低9.7、7.1、4.8、2.2℃。

The influence of molecular weight of dextran(Mw=5000,10000,20000&40000)on the hydration of cement paste and mortar was evaluated via the method of isothermal calorimeter and semi-adiabatic method,respectively.The results indicated that dextran with different molecular weight can inhibit the hydration process of cement.With the increase of relative dextran molecular weight,the induction period of cement hydration shortened,and the peak of hydration heat release rate of cement paste and hydration temperature of cement mortar increased.At the dosage of 0.3%,compared with the control sample without dextran,the peak of hydration heat release rate of cement paste decreased by 55.8%%,35.4%,48.9%and 25.4%at 20℃respectively,and the temperature peaks of cement mortar decreased by 9.7℃,7.1℃,4.8℃and 2.2℃respectively.