再生细骨料中粉料对再生砂浆抗压强度的影响

Effect of powder in recycled fine aggregate on compressive strength of recycled mortar

从2种再生细骨料中筛选出粒径小于0.075mm的粉料作为掺合料,研究其对再生砂浆力学性能的影响.试验结果表明,当稠度保持在70~90mm,再生粉料替代部分水泥或粉煤灰时,再生砂浆的抗压强度基本大于基准再生砂浆;当再生粉料以11%和20%的掺量分别取代水泥和粉煤灰时,再生砂浆的抗压强度最大;采用再生粉料替代粉煤灰的再生砂浆的抗压强度略大于采用再生砂浆替代水泥的再生砂浆,再生粉料与再生细骨料交叉组合得到的再生砂浆的抗压强度增加最为明显.因此,再生粉料可改善再生砂浆中微细颗粒的级配,与水泥、粉煤灰及再生细骨料形成良好级配,从而提高了再生砂浆的抗压强度,发挥填充效应.

The effect of the powder with the particle size of less than 0.075mm screened out from two recycled fine aggregates on the mechanical performance of the recycled mortar is studied.The experimental results show that when a part of cement or fly ash is replaced by the powder and the consistency of the mortar is 70 to 90mm,the compressive strength of the recycled mortar is almost greater than that of the benchmark recycled mortar.In addition,when the cement and the fly ash are replaced by the recycled powder with the mass fractions of 11% and 20%,respectively,the compressive strength reaches a maximum.The compressive strength of the recycled mortar when the cement is replaced by the recycled powder is slightly greater than that when the fly ash is replaced by the recycled powder.And the compressive strength of the cross-combination of the recycled powder and the recycled fine aggregate increases most obviously.Therefore,the recycled powder can improve the gradation of fine particles in the recycled mortar to form a good gradation with cement,fly ash and recycled fine aggregate,which can increase the compressive strength and play a good filling effect.