APAM对全尾砂胶结充填体早期强度影响研究

为探究阴离子型聚丙烯酰胺（APAM）对全尾砂胶结充填体早期强度的影响，采用动态浓密实验装置向全尾砂浆中添加不同单耗和相对分子量的APAM，将所得底流制备成质量浓度为70%、72%、74%，灰砂比为1∶4和1∶8的胶结充填体试块并进行7d抗压强度测试，并借助扫描电镜（SEM）对充填体微观结构进行观察分析。结果表明：APAM对充填体早期强度具有一定的影响，当灰砂比越小、料浆质量浓度越高时，APAM相对分子量越大，对充填体强度影响越大，强度降低越显著；充填体强度随APAM单耗增加先增大后减小；SEM结果表明，APAM引入封闭气孔到充填体中，但适量的APAM能够促进水泥水化反应的进行，充填体内部水化产物黏结更紧密，使充填体早期强度增加；在实验范围内，APAM的最佳单耗为5 g/t。

Influence of APAM on Early Age Strength of Cemented Backfill Based on Unclassified Tailings

In order to determine the influence of anionic polyacrylamide (APAM) on early strength of cemented backfill body of unclassified tailings，experiments on cemented backfill samples (concentration of 70%，72% and 74%，cement-sand ratio of 1∶4 and 1∶8，respectively) with different dosage and relative molecular weight of APAM were conducted by using the dynamic test apparatus of thickener.At the predetermined 7 d curing periods，the cemented backfill samples were subjected to the uniaxial compressive strength tests，and microstructure of backfill body was analyzed by using scanning electron microscope (SEM).The results show that，AMAP has certain influence on the early strength of the backfill body，when the cement-sand ratio is lower and the mass concentration is higher，the larger the molecular weight of APAM is，the more evident the decrease of uniaxial compressive strength of cemented backfill body will be.The strength of cemented backfill first increased and then decreased with increasing the unit consumption of APAM.SEM results show that APAM introduces more enclosed pores into cemented backfill body，however proper amount of APAM can promote the hydration reaction and increase the compactness of hydration products in backfill body，which leads to higher early strength of backfill body. In this experiment，the optimum unit consumption of APAM is 5 g/t.