C-S-H晶核早强剂制备及性能研究

Research on the Preparation and Performance of C⁃S⁃H Core Early-Strengthening Agent

针对常规早强剂可能引起混凝土后期强度倒缩、泛霜等问题,采用聚羧酸减水剂作为分散剂,并以四水硝酸钙和五水合硅酸钠作为原料制备了C⁃S⁃H晶核早强剂,研究了不同反应条件对晶核早强剂稳定性能及强度性能的影响。结果表明:钙硅比为1.5、分散剂相对分子质量为17000时所制备的晶核早强剂具有良好的水泥适应性,其18、24 h的抗压强度比空白组分别提高160%、130%,对后期强度也有一定的促进作用。

Because of the problems caused by conventional early strengthening additives,which could lead to shrinkage of concrete strength and frost formation at an advanced stage,nucleated C-S-H early strengthening additives were created with a solution reaction method using a polycarboxylic acid-type water-reducing agent as the dispersant while using calcium nitrate tetrahydrate and sodium silicate pentahydrate as the raw materials.The stability and strength properties effects of every reaction condition on the nucleated early reinforcing agent were investigated.The results showed that the C-S-H core reinforcing agent prepared with a calcium-silicon ratio of 1.5 and a dispersant relative molecular mass of 17,000 presents satisfied adaptability to cement,and the compressive strength ratios at 18 and 24 hours are above 160%to 130%,respectively,causing promoting effect on the strength at a later stage.In conclusion,the nucleated early reinforcing agent has prospective application value.