Study on the preparation of high performance concrete using steel slag and iron ore tailings

Abstract

For utilize the solid waste synthetically, the cascade grinding technology was used to product cementitious materials with steel slag (SS), iron ore tailings (IOT) and granulated blast furnace slag (GBFS). The effect of SS content and curing process on compressive strength of the high perfor-mance concrete (HPC) were investigated, and the hydration products, microstructure and pore size distribution of hardened paste were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and mercury intrusion method, and the hydration mechanism of cementitious mate-rials mixed with SS was also discussed. The results show that, SS proportion has great influence on the compressive strength of HPC. The dormantperiod is elongated during the hydration by the addition of large amounts of SS in the cementitious materials. Steam curing can effectively stimu-late the activity of SS, and improve the early strength of cementitious materials. In the middle and later age of the hardening process, the coordinat-ed growth of the ettringite (AFt) and C-S-H gels is significant for the strength. After mixed with SS, the proportion of harm hole increase. It is oneof the most important reason for strength decline of HPC.