Preparation of inorganic binder-stabilised material with iron tailings: strength formation and gradation optimisation

This study focuses on mechanical strength and gradation optimisation of inorganic binder-stabilised material with iron tailings for pavement engineering. The mechanical strength and compatibility of iron tailings mortar with various inorganic binders were explored. Mechanical strength formation of iron tailings mortar was analysed using hydration products, micromorphology and microstructures. Composition optimisation of inorganic binder-stabilised material with iron tailings was discussed using the central composite design-response surface method. Results showed that the mechanical strength formation of iron tailings mortar is primarily dependent on ettringite and calcium silicate hydrate (C–S–H) gels. Iron tailings mortars with an appropriate amount of lime or fly ash replacement of cement exhibit a denser structure and adequate pore structure distribution that help improve their mechanical properties compared with cement iron tailings mortars. To balance the amount of iron tailings and the strength of cement-stabilised material, optimal application conditions were proposed for different levels of highways.