Abstract
To prevent environment pollution by hazardous industrial dumps of iron ore treatment sludge, concrete production/demolition debris and lime production waste sustainable cement-less construction materials were developed for substitution of traditional natural raw components excavated in careers, irreversibly destroying natural bonds. Their axial resistance values on the 3rd day of hydration were till 2.34 MPa, on the 28th day - up to 3.94 MPa, on the 180th day 8.40 MPa and on the 365th day 10.22 MPa. The expanding coefficient on the 3rd day were till 2.13%, 2.51% on the 28th day, and on the 365th day 2.22%. Water absorption on the 28th day was 7.17 - 9.32% and decreases to 6.26 - 8.64% on the 90th day. All these characteristics correspond to the Brazilian norms. The physical - chemical processes of materials’ structures formation included alkaline dissociation of solid particles’ surface, with sol appearing and densification till transition to gel. Long-lasting gel compaction and densification to stone-like condition made its structure similar to natural rock materials - silica, opal, obsidian, perlite, pumice, amber, flask, etc. They can be used for production of road bases, concrete blocks and solid unburned bricks, among other sustainable construction materials.
Strength and Microstructure of Concrete with Iron Ore Tailings as Replacement for River Sand