铁尾矿微粉对水泥混凝土后期性能的影响

Effect of iron tailings micropow der on late-property of cement concrete

以铁尾矿微粉为对象研究基准水泥-铁尾矿微粉二元胶凝体系混凝土在水化后期强度、耐久性、孔结构及微观形貌上的发展规律。结果表明:当铁尾矿微粉掺量为20%时,与纯水泥组相比,混凝土抗压强度不降低,且对混凝土后期强度发展有促进作用。混凝土后期抗碳化、抗氯离子渗透能力有一定提高。适量铁尾矿微粉的掺加使得硬化体内部缺陷减少,增大密实度,能减小硬化体最可几孔孔径,减少孔径大于50 nm的有害孔和多害孔数量,且铁尾矿微粉比表面积越大对水泥-铁尾矿微粉硬化体的孔结构优化作用越显著。

The development of the cement-iron tailings micropowder binary cementitious system concrete at the later stage of hydration strength,durability,pore structure and micro-morphology was studied on the basis of iron tailings micro-powder.The results show that when the content of iron tailings micro-powder is 20%,the compressive strength of concrete does not decrease compared with the pure cement group,and it has a promoting effect on the later strength development of concrete.The anti-carbonation and anti-chloride ion permeability of concrete in the later period have been improved.The addition of appropriate amount of iron tailings fine powder reduces the internal defects of the hardened body,increases the compactness,can reduce the pore size of the most measurable pores of the hardened body,and reduces the number of harmful pores and multi-pore pores with pore diameters greater than 50 nm,and the ratio of iron tailings powder.The larger the surface area,the more significant the pore structure optimization effect of the hardened cement-iron tailings powder.