Application of carbon black in conductive fly ash geopolymer mortars

Abstract

Materials with enhanced electrical properties are widely studied concerning their future application in smart or self-sensing constructions. Carbon black is known as one of the inexpensive multipurpose admixtures used in polymeric materials. This study is focused on the application of carbon black in fly ash geopolymer mortar to enhance its conductivity and other electrical properties. Geopolymer samples were prepared with the carbon black content from 0.5 to 4.0% to evaluate their performance in selected electrical properties (conductivity, resistance, capacitance). Further investigations included its influence on the mechanical properties (compressive and flexural strength) and microstructure of the binder (mercury intrusion porosimetry, SEM). Despite the considerable improvement in conductivity, the amount of conductive filler over 2% was also associated with increased porosity and reduced compressive strengths.

Self-Sensing Properties of Fly Ash Geopolymer Doped with Carbon Black under Compression

“…The CB 05 mixture exhibited an almost linear increase in this dependence, which is related to the formation of a large number of microdefects, which, however, do not significantly affect the integrity of the material. The CB 1 mixture then demonstrates the effect of the added carbon black, where the AE activity at the beginning of loading is comparable to the reference mixture, but then increases significantly due to the lower compressive strength [ 26 ]. In the case of the CB 2 mixture, the curve is very flat because there is no significant AE activity in this part due to the higher ductility of the composite.…”