机制砂中絮凝剂含量波动对混凝土性能的影响研究

Research on the Influence of Fluctuation of Flocculant Content in Mechanism Sand on Concrete Performance

本文选用机制砂行业普遍使用的阴离子型聚丙烯酰胺(PAM,分子量2×10~7 Da)作为絮凝剂,研究了机制砂中絮凝剂含量的波动对不同标号混凝土性能的影响。研究结果表明:在控制混凝土配合比不变的条件下,絮凝剂含量由0‰提高至0.03‰,混凝土出机时的坍落度、扩展度变小,混凝土的工作性变差;在絮凝剂含量由0.03‰降低至0‰时,混凝土会出现离析、泌水的问题,且C30混凝土的泌水率高于C50的,破坏了混凝土的匀质性,导致混凝土的抗压强度不合格。

This article selects anionic polyacrylamide (PAM,molecular weight 2×10~7 Da),commonly used in the mechanism sand industry as a flocculant,and investigates the effect of the fluctuation of flocculant content in mechanism sand on the performance of different strength grades of concrete.The results show that,under the condition of keeping the concrete mix ratio constant,the flocculant content increases from 0‰to 0.03‰,and the slump and expansion of the concrete at the time of discharge decrease,resulting in a deterioration of the workability of the concrete.When the content of flocculant decreases from 0.03‰to 0‰,concrete experiences segregation and bleeding problems;and the bleeding rate of C30 concrete is higher than that of C50,which degrades the uniformity of concrete and leads to substandard compressive strength.