多固废混凝土抗压性能及微观结构研究

Study on the compressive performance and microstructure of multi-solid waste concrete

为解决铁尾矿粉堆积问题,促进铁尾矿粉的资源化再利用,采用铁尾矿粉、钢渣粉、磷渣粉作为掺合料替代水泥制备混凝土,研究不同水胶比、铁尾矿粉研磨时间、掺合料掺量及掺合料配合比对混凝土抗压强度的影响。结果表明:水胶比为0.46促进了三元掺合料的后期水化反应,机械研磨2.0 h有助于提高铁尾矿粉活性,钢渣粉与磷渣粉有耦合作用,钢渣粉水化生成Ca(OH)_(2)有助于磷渣粉水化,当铁尾矿粉、磷渣粉、钢渣粉掺量分别为6.0%、8.0%、16.0%时,混凝土28 d强度达到45.0 MPa。微观分析表明,掺合料掺量为30%时试件孔隙率优于掺量20%的试件,增加掺合料掺量能改善混凝土孔结构。

In order to solve the problem of iron tailing powder accumulation and promote the resourceful reuse of iron tailing powder,steel slag powder and phosphorus slag powder were used as admixtures instead of cement to prepare concrete,exploring the effect of ternary admixtures on the compressive strength of concrete,and testing the effect of different water cement ratios,the grinding time of iron tailing powder,the amount of admixtures,and the ratio of admixtures on the compressive strength of concrete.The results showed that 0.46 water-binder ratio promoted the late hydration reaction of ternary admixture,mechanical grinding for 2.0 h helped to improve the activity of iron tailing powder,steel slag powder and phosphorus slag powder had a coupling effect,and the generation of calcium hydroxide by the hydration of steel slag powder helped the hydration of phosphorus slag powder.When the dosage of iron tailing powder,phosphorus slag powder and steel slag powder are 6.0%,8.0%and 16.0%respectively,the strength reached up to 45.0 MPa at 28 d.The microanalysis showed that when the dosage of admixture is 30%,the porosity of spcimen is better than that with 20%dosage,the admixture optimized the pore structure of the concrete.