钢-聚丙烯纤维再生砂浆性能试验研究

通过正交试验研究了粉煤灰掺量、再生细骨料替代率、钢纤维掺量、聚丙烯纤维掺量对再生砂浆的抗压、抗折强度及抗冻性的影响。结果表明,随着钢纤维掺量的增加,抗压、抗折强度明显增大,对砂浆的抗冻性影响不大;聚丙烯纤维对砂浆的强度及抗冻性无显著影响,但可以改变砂浆的脆性;随着再生细骨料替代率的增加,强度及抗冻性均显著增强;随着粉煤灰掺量的增加,砂浆强度及抗冻性明显降低。经过数据拟合,再生砂浆的抗压强度相比抗折强度与抗冻性具有更好的相关性。采用正交分析法得出不掺粉煤灰、再生细骨料替代率为45%,钢纤维掺量为1.5%,聚丙烯纤维掺量为0.1%时,再生砂浆性能最优。在此基础上,通过质量分数为1%、2%、3%、4%的HCl对骨料进行改性处理,结果显示,2%质量分数的HCl改性效果最好。

Experimental Study on Properties of Steel-polypropylene Fiber Recycled Mortar

The effects of fly ash content, recycled fine aggregate replacement rate, steel fiber content and polypropylene fiber content on the compressive strength, flexural strength and frost resistance of the recycled mortar were studied by orthogonal test. The results show that with the increase of the steel fiber content, the compressive and flexural strength of mortar increase significantly, but there is little effect on the frost resistance of mortar. Polypropylene fiber has no significant effect on the strength and frost resistance of the mortar, but it can change the brittleness of the mortar. With the increase of the replacement rate of recycled fine aggregate, the strength and frost resistance of mortar are significantly enhanced. With the increase of fly ash content, the strength and frost resistance of the mortar decreased significantly. After data fitting, the compressive strength of recycled mortar has a better correlation with frost resistance than the flexural strength. The orthogonality analysis method was used to get the best performance condition of recycled mortar, without fly ash, the replacement rate of recycled fine aggregate is 45%, the steel fiber content is 1.5%, and the polypropylene fiber content is 0.1%. On this basis, the aggregates were modified with hydrochloric acid of 1%, 2%, 3% and 4% respectively,and the results show that the hydrochloric acid of 2% has the best modification effect.