蔗糖对水泥水化历程的影响

通过研究蔗糖对水泥凝结时间、水化热、化学收缩及抗压强度等的影响,探讨了蔗糖对水泥水化历程的影响规律及调凝机理。结果表明;蔗糖的掺量存在一个临界值,低于此掺量时,随着蔗糖掺量的增加,凝结时间逐渐延长;高于此掺量时,凝结时间迅速从最大值回落,直至促凝,净浆强度显著降低。在蔗糖作用下,预诱导期出现一个温度高峰,且峰值随掺量的增大而升高,加速期温峰逐渐减小且后移,水泥水化8h内,化学收缩随蔗糖掺量的增大而增加,化学收缩随掺量的增大而降低。蔗糖对水泥浆具有增溶作用,促进铝酸三钙及中间相的水解,加速钙钒石的生成。

INFLUENCE OF SUCROSE ON CEMENT HYDRATION PROCESS

Effects of sucrose on setting time, heat of hydration, chemical shrinkage and strength of cement were studied.The corresponding hydration process and regulation mechanism were discussed. Results show that there exists a critical amount of sucrose.Sucrose acts as retarder at a lower addition, retarding action of sucrose decreases quickly until acting as accelerating action. The temperature peak in pre-inducement period is rather high and the peak value increases with the amount of sucrose at a higher addition. The period of acceleration is delayed and temperature peak is reduced. Chemical shrinkage increases along with the amount of sucrose during 8 h after mixing. After 8 h, chemical shrinkage is reduced. Sucrose can accelerate the solution for cement paste, the hydration of tricalcium aluminate, and the formation of ettringite.