Effects of different curing methods on the properties of recycled coarse aggregate prepared from iron tailings sand
To improve the utilization rate,the pelletizing technology was adopted to prepare coarse aggregate from i-ron tailings sand.The iron tailings sand,after interface pretreatment,was sprayed with a pretreatment liquid of water mist,which was mixed with cementitious materials to generate aggregate particles.Finally,the aggregate particles were cured to obtain recycled coarse aggregate.Moreover,the effects of different curing methods on the properties of recycled coarse aggregate were explored,and the effect of curing methods on the micromorphology and pore structure of recycled coarse aggregate was additionally explored by combining SEM and MIP.Results showed the feasibility of using the improved pelletizing technology to prepare recycled coarse aggregate of iron tailings sand.Moreover,the performance of aggregates under natural curing conditions was the worst,the crushing index of steam curing aggre-gates was the smallest,and the water absorption of carbonated curing aggregates was the smallest.In terms of micro-structure,the aggregate system cured by carbonization had a dense structure,relatively few pores,and microcracks.Therefore,the water absorption of aggregate was the smallest;the hydration product of steam curing contained a large amount of calcium silicate hydrate with gelatinous and netlike structures,needle-like ettringite,and a small amount of calcium hydroxide crystals;The crushing index was small.These findings guide the preparation of recycled coarse aggregate from iron tailings sand and its application in the subsequent service of concrete.
iron tailings sandrecycled coarse aggregatecuring methodsutilization ratemicrostructurecrushing indexwater absorptionconcrete