Enhanced acid resistance of ternary blended concrete composites transformed with graphene oxide for sewer structures

This paper aims to enhance the durability of concrete against acidic environments for sewer structures through developing graphene oxide-tailored ternary blended nano-concrete composites (GO-TBNCCs) and conducting a series of experimental studies. The acceleration test was carried out by immersing the concrete samples prepared with different dosages of GO in a corrosive H2SO4 solution with a pH of 1.0. Residual strength, acid resistance, surface pH, water absorption, and degradation (corrosion) depth were measured accordingly. Visual inspection was also conducted for comparison purposes. In contrast to the control mixes, the blend with 20% fly ash (FA) and 40% ground granulated blast-furnace slag (GGBFS) reinforced with 0.0457 wt% GO demonstrated the maximum improvement to acid resistance. This significant corrosion resistance of GO-TBNCCs was evident by a 94% reduction in strength loss, 83% decrease in corrosion depth, 65% increase in strength, 59% lower water absorption, and ∼87% drop in mass and physical measurement losses. It shows that the well-dispersed GO-colloidal solution, treated with a polycarboxylate ether-based superplasticizer, could result in higher zeta potential, smaller hydrodynamic diameter, reduced flake size, and lower defect ratio. This enables GO nano-filling potential to be integrated into the concrete matrix seamlessly and the formation of a denser microstructure that limits the penetration of aggressive chemical ions from an acidic environment through the synergistic interaction of GO-GGBFS-FA three-phase system, ultimately leading to substantial performance enhancement. Thus, the promising GO-infused ternary blended concrete technology developed in this research could potentially significantly strengthen the acid resistance characteristics of concrete structures within the extreme conditions of sewage systems.