The Mechanical and Erosion Resistance Properties of an Alkali-activated Steel Slag Cementitious System

To examine the effect of particle size distribution characteristics and activator complex admixtures of steel slag cementitious systems on the physical and mechanical properties of steel slag concrete, the volume stability of steel slag powder was tested by the disk method and Le Chatelier clamp method. The appropriate steel slag grinding time and activator mixture ratio were selected through the characterization of particle size distribution and mechanical properties. Three activators, 4% Na2SO4, 1% NaOH, and 1% Na2SiO3, were added to the standard steel slag concrete as a single additive, pairwise double mixture and triple admixture. A set of steel slag concretes of higher compressive strength was tested for sulfite-erosion resistance, and the erosion resistance property of steel slag concrete within the 8-m erosion period was analyzed. The test results indicate that the proper slag grinding time is 30 min. The activator can significantly enhance the activity of steel slag and improve the strength of the concrete. The excitatory effect of single dosing 1% NaOH on steel slag concrete is most evident, the strength at 28 d exceeds that of ordinary concrete. The 28-d compressive strength of steel slag concrete shows evident distinctions when using different activators. The steel slag concrete with the triple activator admixture has the best results; its growth value of 28-d strength reaches 23.4% compared with that of the steel slag concrete without the activator. The addition of different activators triggers different effects on the anti-erosion property of steel slag concrete, but overall, it is conducive to erosion resistance.