Influence of Steel Slag Content on the Characteristics of “One-step” Alkali-activated Composite Cementitious Materials

Abstract

A solid, fast-dissolving sodium silicate was used as an alkaline activator. Granulated blast furnace slag (GGBS), metakaolin (MK), and steel slag (SS) were used as the cementious components to prepare a ternary composite cementitious material known as alkali-activated steel slag composite cementitious material (ASCM) by the “one-step method”. The impacts of cementitious components, alkali activator modulus, and Na₂O% on the mechanical strength were investigated, and the hydration products and hydration kinetics of ASCM were analyzed. The experimental results reveal that XRD, FTIR, SEM, EDS, and exothermic heat of hydration show that when GGBS:MK:SS=60wt%:10wt%:30wt%, the activator modulus is 1.2, and the alkali content is 5.5wt%, the 28 d flexural strength of ASCM mortar is 12.6 MPa, and the compressive strength is 53.3 MPa, the hydration products consist of C-S-H gel/C-A-S-H gel, mullite (3Al₂O₃-2SiO₂), calcite (CaCO₃), quartz, etc. ASCM has a large initial hydration exotherm rate but a small cumulative exotherm.

Keywords

solid activator / “one-step” alkali-activated composite cementitious materials / steel slag

RIGHTS & PERMISSIONS

Wuhan University of Technology and Springer-Verlag GmbH Germany, Part of Springer Nature