Mechanical Performance and Micro-structure of Pore Steel Slag Block Prepared by Accelerated Carbonation

Abstract

Steel slag contains a large amount of calcium silicate, which can react with CO₂ to generate CaCO₃ and SiO₂ colloid, thus steel slag may become a cementitious material with a certain strength. High strength porous steel slag carbonated brick was prepared by adding easily decomposed bicarbonate solid into steel slag as pore-forming agent and then accelerating carbonation. A variety of characterization methods were used to characterize the composition and micro-structure of the samples. The effects of different pore-forming agent dosage and carbonation time on the properties of pore steel slag blocks were discussed. The results show that the addition of ammonia bicarbonate promotes the nucleation and growth of columnar calcite. The strength of steel slag block mixed with 30% pore forming agent can reach 24.8 MPa after 1 day of carbonation, and then the strength development tends to slow down.

Keywords

steel slag / accelerating carbonation / pore-forming / ammonia bicarbonate / calcite