铁尾矿—硅锰渣—赤泥协同制备超高性能混凝土力学性能研究

Study on Mechanical Properties of Ultra-high Performance Concrete Prepared with Iron Tailings,Silico-manganese Slag and Red Mud

选用铁尾矿粉、硅锰渣粉和赤泥作为矿物掺合料代替部分普通硅酸盐水泥,协同制备了2种不同水胶比的超高性能混凝土,研究了掺入铁尾矿—硅锰渣—赤泥的超高性能混凝土(Ultra-high Performance Concrete,UHPC)的力学性能,探究了铁尾矿粉掺量对UHPC的抗弯强度、劈裂抗拉强度和抗压强度的影响。结果表明:①水胶比较低的超高性能混凝土中,铁尾矿粉对混凝土抗弯强度影响较大,对劈裂抗拉强度影响较小;②水胶比较高的超高性能混凝土中,铁尾矿粉对混凝土抗弯强度的影响与对劈裂抗拉强度的影响基本一致;③随着铁尾矿粉掺量增加,水胶比为0.20和0.25的超高性能混凝土抗压强度降低,硅锰渣—赤泥组超高性能混凝土28 d抗压强度最大降低幅度分别为19.2%和22.9%。上述分析进一步反映出:①铁尾矿粉在超高性能混凝土中的掺量不宜超过矿物掺合料总量的40%;②铁尾矿粉的掺加不利于超高性能混凝土的早期抗压强度提升,但适量掺加铁尾矿粉(20%)有利于超高性能混凝土后期抗压强度增长;③三参数模型系数相对于铁尾矿—硅锰渣—赤泥超高性能混凝土的抗压强度和养护龄期关系相对集中,拟合相关系数较高。

Two kinds of ultra-high performance concrete with different water-binder ratios were prepared by using iron tailing powder,silicomanganite slag powder and red mud as mineral admixtures to replace some ordinary Portland cement.The mechanical properties of Ultra-high Performance Concrete(UHPC)mixed with iron tailings,silica manganese slag and red mud were studied,and the effects of iron tailing powder content on the bending strength,splitting tensile strength and compressive strength of UHPC were investigated.The results show that:①In the ultra-high performance concrete with low water-binder ratio,the iron tailing powder has a greater effect on the bending strength of the concrete,but a smaller effect on the splitting tensile strength;②In the ultra-high performance concrete with high water-binder ratio,the influence of iron tailing powder on the bending strength of concrete is basically the same as that on the splitting tensile strength;③With the increase of iron tailing powder content,the compressive strength of ultra-high performance concrete with water-binder ratio of 0.20 and 0.25 decreases,and the maximum compressive strength of ultra-high performance concrete with silica manganese sludge-red mud group decreases by 19.2%and 22.9%at 28 days,respectively.The above analysis further reflects that:①the content of iron tailing powder in ultra-high performance concrete should not exceed 40%of the total mineral admixture;②The addition of iron tailing powder is not conducive to the improvement of early compressive strength of ultra-high performance concrete,but the appropriate addition of iron tailing powder(20%)is conducive to the late compressive strength of ultra-high performance concrete;③The relationship between compressive strength and curing age of ultra-high performance concrete with iron tailings,siliconmanganese slag and red mud is relatively concentrated,and the fitting correlation coefficient is higher.