Effects of Black Scoria on Mechanical Properties and Thermal Insulation Properties of Building Materials

Abstract

The effect of fine black scoria on the mechanical properties and thermal conductivity of building materials was investigated in this study. Black scoria was used to replace cement in concrete with various percentages. Four concrete samples containing 0%, 10%, 20%, and 30% black scoria were prepared. Characterization black scoria was performed via X-ray powder diffraction, X-ray fluorescence, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry analysis. Then, the compressive strength of the samples was investigated after 14, 21, 28, and 91 days of curing at room temperature. Finally, the thermal conductivities of the samples were measured after 28 days. Based on the experimental results, the highest compressive strength among the samples was 45.3 MPa, obtained from the mixture containing 10% black scoria after 91 days of curing. It was also observed that the average thermal conductivity of the concrete samples decreased with an increase in the fine black scoria content from 1.8 to 0.193 W m−1 K−1. Thus, black scoria is an appropriate substitute for commercial admixtures in cement composites in thermally insulating building materials due to its low density, excellent compressive strength, and good heat insulation properties.