Preparation of self-heating alkali-activated materials using industrial waste products

Abstract

Recently, materials with enhanced electrical properties appeared as very good candidates for self-heating applications. When exploited for icing prevention or deicing of roads, pavements, or runways, they may bring environmental benefits as they do not load the environment with chemicals, salts in particular. Utilization of waste products instead of traditional materials, such as Portland cement, makes these materials even friendlier to the environment. In this paper, three alkali-activated materials composed of slag, water glass, aggregates, water, and carbon black as an electrically conductive admixture are analyzed and compared to a reference one without any conductive admixture. Experimental results show that the designed materials have a very favorable combination of mechanical- (compressive strength up to 44 MPa and flexural strength up to 9 MPa) and electrical (electrical conductivity up to ∼55 × 10−3 S/m) properties. Satisfactory self-heating properties in a low-voltage range are exhibited as well; 45 V DC heating of the samples can increase their temperature by up to 39 °C. The environmental assessment indicates that the designed alkali-activated materials can be considered as promising alternatives to cement-based composites with similar properties, reducing the carbon dioxide production by up to 44%.