Effect of neutral activator on properties of steel slag powder-cement composite cementitious material

Abstract

In this paper, the physical and mechanical properties of TISCO steel slag were tested by different ratios of composite activators. The optimal neutral composite activator was determined, and the properties of neutral activated steel slag power-cement composite cementitious material with 30% cement content were studied. The experimental results indicated that the best ratio of gypsum: silica fume: sodium sulfate: sodium aluminate: selfmade activator was 2.5:2.5:1:0.5:0.5. Through XRD, SEM and TG-DTG detection, less stable periclase was found at 30% cement content and activated steel slag slurry. After 28d curing, the micro morphology and compactness of hydration products were not different from those of cement, and there were even no incompletely hydrated particles. The voids between hydration products and the interface of different hydration products were continuously filled with hydration products over age. C-S-H and AFt generated by 7d activated SSP cement composite powder was greater than those of cement. At 28d, a small amount of Ca(OH)2 was generated. The results show that the combination of self-made neutral activator and other activators can improve the properties of cement steel slag powder composite cementitious material and improve the utilization rate of steel slag.