铁尾矿粉对干粉砂浆性能的影响及机理分析

Effect and Mechanism Analysis of Iron Tailings Powder on Performance of Dry Mortar

为了研究不同比例铁尾矿粉掺量对干粉砂浆和易性、力学性能以及微观机理的影响,采用白象山铁尾矿粉作为研究对象,以不同比例替代干粉砂浆中机制砂和水泥的用量进行试验。研究结果表明:在粉体材料和机制砂总量保持不变的情况下,随着铁尾矿粉替代率的增加,干粉砂浆力学性能逐渐降低;铁尾矿粉以10%的比例替代机制砂,满足M20砂浆和易性及力学性能要求且性能最优;当铁尾矿粉对机制砂和水泥替代率达到30%时,满足M5砂浆和易性和力学性能要求。早期掺入铁尾矿粉能够加速水泥的水化,提高水化程度,生成更多的氢氧化钙;铁尾矿粉中的硅氧断键和铝氧断键在Ca(OH)_(2)作用下发生重聚反应,生成以硅酸钙、硅铝酸钙为主要成分的复盐矿物;掺入铁尾矿粉后,砂浆结构较为松散,强度降低。在10%~30%掺量替代机制砂和水泥的情况下,干粉砂浆能符合标准规范要求。

In order to study the effect of different proportion of iron tailings powder on workability,mechanical property and microscopic mechanism of dry mortar,experiments of iron tailings powder were used as the research object to replace the machine-made sand and cement.The results show that the me⁃chanical property of dry-mixed mortar was decreased with the increase of iron tailings powder when the to⁃tal amount of powder material and machine-made sand remain the same.When the iron tailings powder was used to replace the machine-made sand with 10%,the performance of M20-mortar was the best and met the requirement of workability and mechanical property.When the replacement rate of iron tailings powder to machine-made sand reaches 30%,the workability and mechanical property of M5-mortar can be met.The incorporation of iron tailings powder can accelerate the hydration of cement,increase the degree of hy⁃dration,and generate more Ca(OH)_(2) at early age.The silicon-oxygen break bond and aluminum-oxygen break bond in iron tailings powder can reunite under the action of Ca(OH)_(2) and form the double-salt min⁃erals with calcium silicate and calcium silico-aluminate.The mortar’s structure was loose when the iron tailings powder was added,so its compressive strength was decreased.Dry-mixed mortar can meet the stan⁃dard of specification requirement when 10%to 30%mechanical sand and cement were replaced by iron tailings powder.