关键词: 高硅型铁尾矿, 蒸压加气轻质混凝土, 混合比例, 水胶比, 流动性, 抗压强度, 干体积密度, 水化产物

Abstract: In order to find a substitute of highcost silica aggregate and improve the utilization rate of highsilicon iron tailings，the autoclaved aerated lightweight concrete (ALC) was prepared by mixing highsilicon iron tailings and fly ash instead of silicon sand，and the influence of the mixing ratio of iron tailings with fly ash and waterbinder ratio on the performance of autoclaved aerated lightweight concrete were analyzed.XRD and SEM were used to analyze the hydration products and microstructure.The results showed that the dry volume density of specimen increases gradually，and the compressive strength increases first and then decreases with the increase of iron tailings proportion.With the increase of waterbinder ratio，the dry volume density and compressive strength of the specimen decrease gradually.When the mass ratio of iron tailings，fly ash，cement，lime and desulfurized gypsum is 62.8∶9.0∶16.9∶8.9∶2.4 and the waterbinder ratio is 1.40，the compressive strength and dry volume density of the specimen prepared are 4.15 MPa and 576 kg/m3,which meets the requirements of strength grade A3.5 and dry volume density grade B06 in stipulated of Autoclaved Aerated Concrete Block (GB/T 11968—2020).XRD results showed that the main hydration products are quartz，tobermorite，silicacalcium hydrate and zeolite.SEM analysis further showed that a large number of platelike tobermorite and a small amount of C—S—H gel are formed during hydration.The good network structure makes it difficult to cause stress concentration under pressure.

Key words: high silicon iron tailings, autoclaved lightweight concrete, mixing ratio, waterbinder ratio, fluidity, compressive strength, dry volume density, hydration products