Test research on the effects of mechanochemically activated iron tailings on the compressive strength of concrete

• High-silicon iron tailings were mechanochemically activated.
• Activated tailings were taken as a supplementary cementing material in concrete.
• The compressive strength of concrete may be as required at some mix proportions.
• The maximum cement substitution rate is 30% in common concrete.
• With a proper admixture, the cement substitution rate can be up to 40%.

High-silicon iron tailings, which have been mechanochemically activated, was used for the preparation of concrete as a supplementary cementing material to substitute cement (by 10%, 20%, 30% and 40% respectively) based on their composition, particle sizes and pozzolanic activity. With the aid of tests, this paper discusses the effects of the tailings on the compressive strength of concrete. Tests show that with an increase in substitution rate of cement in the tailings, the compressive strength of concrete tends to decrease, and when the substitution rate is at 10%, 20% and 30% respectively, the compressive strength of concrete is measured up to the design requirement; if an appropriate amount of water reducing admixture is added while cement is substituted by tailings with a substitution rate of 10%, 20%, 30% and 40% respectively, the compressive strength of concrete is also measured up to the design requirement. The research result demonstrates that as far as the compressive strength concerned, it is feasible to use mechanochemically activated high-silicon iron tailings as a supplementary cementing material to partly substitute cement in concrete.