Effect of Composition of Geopolymer Composites Containing Fly Ash and Waste Glass Powder on Their Durability and Resistivity Demonstrated in Presence of a Nanocarbon Additive in a Form of Graphene

The objective of this study was to obtain a geopolymer composite with semi-conductive or conductive properties for self-control of abnormal symptoms caused by damages to its microstructure. For that purpose effects of different content of fly ash, waste glass powder, as well as two types of graphene and hydrophilic and hydro-phobic nanosilica on electrical, physical and mechanical properties were tested. Measurements of resistivity showed the capacity for electrical charge flow in composites, which depended on their composition and products of the geopolymer hardening process. Based on results of the electrical charge flow intensity and observations of geopolymer composite microstructure by means of XRD and scanning microscopy, a possible course of the electrical conductivity mechanism in geopolymer materials was indicated. It was found that geopolymer com-posites containing fly ash, as well as addition of graphene and hydrophobic nanosilica, showed the most favourable electrical charge conductivity parameters and the highest strength gain.