含铁尾矿粉和粉煤灰混凝土强度和耐久性研究

Study on Strength and Durability of Concrete Containing Iron Tailings and Fly Ash

研究磨细铁尾矿粉部分取代粉煤灰制备混凝土的抗压强度,利用氯离子渗透,碳化及硫酸盐侵蚀3种方式综合评估复掺粉煤灰和铁尾矿粉混凝土的耐久性,通过扫描电镜(SEM)分析影响机理。结果表明,混凝土抗压强度随铁尾矿粉掺量增加整体呈先增加后减小趋势。磨细铁尾矿粉能与水泥和粉煤灰形成良好的颗粒级配,使混凝土结构更紧密。随着铁尾矿粉掺量增加,混凝土的氯离子渗透扩散系数及28 d碳化深度均呈先减小后增大趋势。掺入适量铁尾矿粉可提高混凝土抗硫酸盐侵蚀能力;掺量过大时,混凝土抗压强度和吸水率随掺量增加逐渐降低。混凝土配合比为50%水泥、15%铁尾矿粉和35%粉煤灰,力学性能及耐久性最优。

The compressive strength of concrete with ground iron tailings instead of fly ash was studied,and the durability of concrete with fly ash and iron tailings was evaluated by chloride penetration,carbonation and sulfate attack,the mechanism was analyzed by scanning electron microscope(SEM).The results show that the compressive strength of concrete increases first and then decreases with the increase of the content of iron tailing powder.The tailings powder can form a good grain gradation with cement and fly ash and make the concrete structure more compact.With the increase of the iron tailing powder content,the chloride ion diffusion coefficient and the carbonation depth in 28 days all first decrease and then increase.The proper amount of iron tailing powder can also improve the resistance of concrete to sulfate attack.When the amount is too large,the compressive strength and water absorption of concrete decrease with the increase of the iron tailings content.When the mix ratio is 50%cement,15%iron tailings powder and 35%fly ash,the mechanical properties and durability of the concrete are the best.