铁尾矿基多固废混凝土耐酸侵蚀性能研究

Study on Acid Erosion Resistance of Iron Tailings Based Multi Solid Waste Concrete

为提高混凝土材料的耐酸侵蚀性能,同时实现大宗固废的综合利用,以铁尾矿、钢渣及脱硫灰为掺合料,铁尾矿砂及铁尾矿废石为骨料制备混凝土试块,研究了水泥替代率及水胶比对混凝土试块28 d抗压强度及酸侵蚀60 d后抗压强度、质量损失、表观劣化及中性化深度的影响。结果表明:①当水胶比一定、水泥替代率为10%时,混凝土试块28 d的抗压强度最高,且高于纯水泥混凝土试块的抗压强度;当水泥替代率一定、水胶比为0.42时,混凝土试块28 d的抗压强度最高。②当水胶比一定、水泥替代率大于15%时,酸侵蚀60 d后的混凝土试块表现出较强的耐酸侵蚀性能;当水泥替代率一定、水胶比小于0.45时,酸侵蚀60 d后的混凝土试块表现出较强的耐酸侵蚀性能。③当水胶比一定、水泥替代率为30%时,达到最小的质量损失;当水泥替代率一定、水胶比为0.42时,达到最小的质量损失;且均小于纯水泥混凝土试块的质量损失。④复合掺合料体系使得混凝土的内部结构致密、孔隙细化,有效地阻碍了醋酸溶液对混凝土的侵蚀,降低了混凝土试块的中性化深度。总体上看,铁尾矿、钢渣、脱硫灰进行复掺制备混凝土,具有优于纯水泥混凝土的耐酸侵蚀性能。

In order to improve the acid erosion resistance of concrete materials and realize the comprehensive utilization of bulk solid waste,concrete specimens were prepared with iron tailings,steel slag and desulfurized ash as admixtures,iron tailings and iron tailings waste rock as aggregate.The influence of cement replacement rate and water-binder ratio on the 28 d compressive strength,mass loss,apparent deterioration and neutralization depth of concrete specimens after 60 d acid erosion were studied.The results showed that:①When the water-binder ratio is constant and the cement replacement ratio is 10%,the compressive strength of concrete specimens at 28 days is the highest,which is higher than that of pure cement concrete specimen.When the cement replacement rate is constant and the water-binder ratio is 0.42,the compressive strength of the concrete specimen is the highest after 28 days.②When the water-binder ratio is constant and the cement replacement ratio is more than 15%,the concrete specimen show strong acid resistance after 60 days of acid erosion.When the cement replacement rate is constant and the water-binder ratio is less than 0.45,the concrete test blocks show strong acid erosion resistance after 60 days of acid erosion.③When the water-binder ratio is constant and the cement replacement rate is 30%,the minimum mass loss could be achieved.When the cement replacement rate is constant and the water-binder ratio is 0.42,the minimum mass loss can be achieved.All are less than the mass loss of pure cement concrete test block.④The compound admixture system makes the internal structure of concrete dense and pores refined,effectively hinders the erosion of acetic acid solution on concrete specimen,and reduces the neutral depth of concrete specimen.In general,concrete prepared by mixing iron tailings,steel slag and desulfurized ash has better acid erosion resistance than pure cement concrete.