粉煤灰及矿粉对水泥基注浆料性能的影响

以硅酸盐和硫铝酸盐复合水泥为基材制作水泥基注浆材料,分别讨论了不同类型、不同掺量的粉煤灰和矿粉对水泥基注浆材料的流动度、容重、膨胀率、抗压抗折强度的影响。结果表明:粉煤灰能有效地增加水泥基注浆料的流动度,当粉煤灰掺量低于20%时,可以提高注浆料的塑性膨胀率,当Ⅰ级粉煤灰掺量为20%或Ⅱ级粉煤灰掺量为15%时,3 h膨胀率最高达1%;粉煤灰对注浆料的早期强度不利,但可以增强其后期强度。矿粉可以改善其流动度,随着矿粉的增加,注浆料的容重和膨胀率均呈下降趋势;矿粉对注浆料的28 d强度无显著影响,其早期强度随着矿粉的增加而下降,当S75矿粉掺量高于7%或S95矿粉掺量高于11%时,抗压抗折强度不满足规范要求。

Effect of Fly Ash and Mineral Powder on Properties of Cement-based Slurry

In order to overcome the shortcomings of current cement-based grouting materials,such as poor fluidity,self-shrinkage and high cost,cement-based grouting materials are prepared based on silicate and sulphoaluminate composite cement.The effects of different types of fly ash and mineral powder on the fluidity,bulk density,expansion ratio and compressive flexural strength of cement-based grouting materials were discussed.The results show that fly ash can effectively increase the fluidity of cement-based grouting.When the fly ash content is less than 20%,fly ash can effectively improve the plastic expansion rate of grouting.When the coal ash content is 20% or the second-grade fly ash content is 15%,the 3 h expansion rate is up to 1%;the fly ash is unfavorable to the early strength of the injection slurry,but it can enhance its late strength.The ore powder can effectively improve its fluidity.With the increase of ore powder,the bulk density and expansion ratio of the slurry show a downward trend;the ore powder has no significant effect on the 28 d strength of the slurry,and its early strength follows the mineral powder.The increase and decrease,when the S75 mineral powder content is higher than 7% or the S95 mineral powder content is higher than 11%,the compressive and flexural strength cloth meets the specification requirements.