A Study on the Activation of Carbide Slag Cementitious Materials

Abstract

This research used orthogonal testing methods to study the effect of stimulator content on the properties of carbide slag (CS) cementitious materials. Range and variance analyses reveal that different stimulators do not significantly affect the consistencies and setting times of these cementitious materials, but influenced considerably their flexural and compressive strengths; the influence decreases in the order: NaOH> CaCl2> Na2SO4> Na2SiO3. Further analyses show that the strengths of these cementitious materials increase with increasing NaOH content, and decrease with increasing CaCl2 content. When the mass ratio of Na2SO4: Na2SiO3: CaCl2: NaOH was 1: 1: 0: 5, the stimulators exhibited the best activating effect. X-ray diffraction (XRD) and Scanning electron microscope (SEM) analyses showed that the 28-day hydration products contain large amounts of ettringite (AFt), calcium silicate hydrate (C-S-H), calcium aluminate hydrate (C-A-H), and small amounts of unreacted Ca(OH)2 and quartz. These hydration products increased the strengths of these cementitious systems.