不同缓凝剂与减水剂对无碱速凝剂的影响

Effect of Retarding Ingredients Mixed with Water Reducing Agent on Alkali Free Accelerator

本文研究了不同种类缓凝剂、减水剂对无碱速凝剂凝结时间的影响,其中探究了白糖、三聚磷酸钠两种缓凝成分与减水剂C7及羟丙基甲基纤维素(HPMC)混合后分别对三种水泥掺无碱速凝剂的凝结时间与一天抗压强度的影响。实验表明,减水剂C7(掺量0.08%)对于无碱速凝剂初终凝有延缓作用,对一天强度没有影响;白糖对无碱速凝剂缓凝效果最好,三聚磷酸钠对无碱速凝剂缓凝效果最差;白糖(掺量0.03%)、三聚磷酸钠(掺量0.03%)混入减水剂C7对无碱速凝剂初凝时间影响不大,略微加快了终凝时间,三聚磷酸钠加快终凝时间的效果比白糖稍强;对于一天强度来说,无论是三聚磷酸钠还是白糖都降低了砂浆试块的一天强度,白糖比三聚磷酸钠的降强效果更突出,再加入HPMC(掺量0.0015%)后,初终凝结时间比空白慢,一天强度也会增强。

The influence of retarder and superplasticizer on the setting time of alkali free accelerator,and the influence of sugar and Sodium Tripolyphosphate on the setting time and one-day strength of three kinds of cement paste mixed with alkali free accelerator after mixing with superplasticizer C7 and HPMC.The experimental results show that superplasticizer C7(0.08%)can delay the initial and final setting of alkali free accelerator,and has no effect on one-day strength;White sugar has the best retarding effect on alkali free accelerator,and sodium tripolyphosphate has the worst retarding effect on alkali free accelerator;White sugar(0.03%)and sodium tripolyphosphate(0.03%)mixed with superplasticizer C7 have little effect on the initial setting time of alkali free accelerator,and slightly accelerate the final setting time.The acceleration effect of sodium tripolyphosphate is slightly stronger than that of white sugar.For one-day strength,both sodium tripolyphosphate and white sugar reduce the one-day strength of accelerator,and the strength reduction effect of white sugar is more prominent than that of sodium tripolyphosphate.After adding HPMC(0.0015%),the initial and final setting time is slower than that without HPMC,and the strength will increase in one day.