High-strength and high-toughness alkali-activated composite materials: Optimizing mechanical properties through synergistic utilization of steel slag, ground granulated blast furnace slag, and fly ash

In this study, the synergistic utilization of steel slag (SS), ground granulated blast furnace slag (GGBS), and fly ash (FA) was investigated to optimize the mechanical properties of high-strength and high-toughness alkali-activated composite materials (AAM). The research focused on understanding how varying ratios of these components affect the workability, compressive strength, elastic modulus, tensile strength, and tensile deformation capacity of high-strength and high-toughness AAM. A key part of the study involved optimizing the SS-GGBS-FA ternary cementitious system in high-strength and high-toughness AAM using the simplex-centroid design methodology. The findings reveal that changes in the proportions of SS, GGBS, and FA predominantly influence the flowability of high-strength and high-toughness AAM to a limited extent. Notably, the amount of GGBS in the cementitious mix significantly affects the compressive strength and elastic modulus of the material. A synergistic enhancement of the tensile properties was observed due to the combined effect of SS, GGBS, and FA. An optimal tensile deformation performance was achieved with approximately 15% SS. For an ideal balance of properties, including tensile strength above 8.1 MPa, ultimate tensile strain exceeding 6.4%, and compressive strength over 95 MPa, the study recommends maintaining SS between 7.5% and 11.5%, GGBS between 31.5% and 35.5%, and FA between 55.5% and 58.5%. These insights are crucial for the design and practical engineering applications of the SS-GGBS-FA ternary cementitious system in high-strength and high-toughness AAM.