Influence of SiO2-doped carbon black nanoparticles on the properties of fly ash-based geopolymer binder for the development of construction and infrastructure

The influence of nanomaterials in enhancing the properties of geopolymers as environmentally friendly substitutes for cementitious composites has been the subject of many studies in the context of the sustainable development of construction materials. However, little attention has been paid to the direct influence of nanomaterials on composite binder properties. The effect of SiO₂-doped carbon black (SCB) nanoparticles as an additive in the fly ash-based geopolymer binder is investigated in this work. Geopolymer specimens were prepared with and without SCB nanoparticles to evaluate the effects of SCB nano additives. The SCB nanoparticles at 0.35 wt% of fly ash, were mixed into geopolymer binder. We investigated the compressive strength, electrical resistivity, and mineralogical properties. The results show that a later age of 91 days demonstrated improvement in the compressive strength of SCB nano additions-based geopolymer (SCB-GP). But at the early ages of 7 and 28 days, SCB-GP heat-cured specimens showed a drop in compressive strength. Electrical properties were measured by, the four-probe method, decrease in voltage was observed at 1 μA constant current for the SCB geopolymer. This study reveals that nano additive-based geopolymer has limitations for early ages compressive strength as the reduction was observed, however, at later ages, results indicate stability in compressive strength and increased conductivity for ambient cured nano additives based geopolymer paste specimen. This research leads to new research pathways for SCB nano-additives based geopolymer as structural materials application.