Mechanical performance and resistance to carbonation of steel slag reinforced concrete

Abstract

The use of residues as alternative materials in the production of cement-based composites is significantly growing since it embraces the circular economy concepts. This alternative reduces the demand for natural resources by the construction sector and provides a proper destination for a range of industrial residues. However, the alternative materials must perform properly for safe applications. In this way, the steel slag, a residue of the steel industry, stands out. The steel slag is already applied in some cement-based composites showing enhancement in the mechanical performance, although its durability is barely evaluated. So, this research produced eco-friendly structural concretes of three compressive strength classes and for similar application parameters. The evaluations were performed in concretes with total replacement of conventional aggregates by steel slag aggregates, containing no chemical admixtures and in the presence of a PCE-based superplasticizer. The mechanical performance and resistance to carbonation of these products were evaluated. An accelerated carbonation test was proposed and adopted to better understand the carbonation phenomenon within the research timeframe. The steel slag concretes presented higher compressive strengths and reductions in carbonation depths up to 60% compared to conventional ones. These results corroborate the technical feasibility of applying steel slag as aggregates in cement-based composites.