Valorization of waste sulfur in synthesis of eco-friendly self-compacting concrete

Abstract

Self-compacting concrete (SCC) typically contains a certain content of very fine mineral fillers such as limestone powder. The idea of this study was to partially replace limestone with elemental waste sulfur since it is hydrophobic, insoluble in water and therefore chemically inert in concrete mixtures. Properties of conventional SCC with limestone and several compositions with different sulfur content were compared. Hardened concrete was tested for compressive, flexural and adhesion strengths, dynamic elasticity modulus, specific electrical resistance, density, microstructure and infrared thermography. Results showed slight decline in compressive, flexural and adhesion strengths as well as in dynamic elasticity modulus. Specific electrical resistance and density were higher for samples with sulfur. SEM analysis indicated slight porosity increase for the sample with sulfur. Infrared thermography was applied as a fast method for detecting internal deformations. Having in mind that all properties should remain or improve in case of waste valorization and the criteria should set to satisfy requirements for SCC, this study proved that all mixtures can be used for certain structural applications.