聚羧酸减水剂复合无碱速凝剂对水泥浆体凝结时间和早期强度的影响

研究了不同聚羧酸减水剂与自制无碱液体速凝剂复合后对水泥浆体凝结时间与早期强度的影响。结果表明:当无碱速凝剂掺量为水泥质量的6%时,复合推荐掺量的不同类型减水剂会显著延缓水泥净浆的凝结时间;当速凝剂掺量提高至7%时,凝结时间会缩短-延长。掺入市售聚羧酸减水剂的水泥净浆在静置30、60 min后再加入速凝剂,与同掺减水剂和速凝剂的水泥净浆相比,凝结时间延缓明显;但采用复合了保坍组分的自制聚羧酸减水剂再加入速凝剂,对水泥浆体的凝结时间影响不大。添加自制聚羧酸减水剂还会对掺无碱速凝剂水泥砂浆的1 d强度有一定的提高。

Effect of polycarboxylate superplasticizer composite alkali-free flash-setting admixture on setting time and early strength of cement paste

The effects of different polycarboxylate superplasticizers and self-made alkali-free liquid accelerators on the setting time and early strength of cement paste were studied.The results show that when the alkali-free flash-setting admixture is 6%of the cement mass,the different types of water-reducing agent recommended by the composite will significantly delay the setting time of the cement paste.When the amount of flash-setting admixture is increased to 7%,the setting time will be shortened and then extended.The cement paste blended with the commercially available polycarboxylate superplasticizer is added with a flash-setting admixture after standing for 30 min and 60 min.Compared with the cement paste mixed with superplasticizer and flash-setting admixture,the setting time was significantly delayed.However,the self-made polycarboxylate superplasticizer combined with maintain slump composition and the addition of flash-setting admixture have little effect on the setting time of cement paste.The addition of the self-made polycarboxylate superplasticizer also has a certain improvement on the 1 d strength of the alkali-free flash-setting admixture cement mortar.