Degradation resistance of graphene oxide-tailored ternary blended concrete under prolonged sulfuric acid exposure

Sulfuric-acid induced deterioration of concrete poses a significant threat to the longevity of sewerage infrastructure. This study investigates the degradation behavior of graphene oxide-tailored ternary blended nano-concrete composites (GO-TBNCCs) under accelerated sulfuric acid exposure (pH 1.0) over 120 days. Twelve mixes were formulated using 20% fly ash (FA), 20–40% ground granulated blast-furnace slag (GGBFS), and varying dosages (0.0275–0.0639 wt%) of polyfunctionalised GO (p-GO). Results reveal that p-GO significantly enhanced strength and durability across all mixes. The optimal mix, 20F40GB639GO, exhibited ∼123% higher residual compressive strength compared to the corresponding acid-exposed control mixture (20F40GB). This translated into a substantial improvement in acid resistance performance (ARP), quantified by reductions in mass, dimensional, and strength losses of approximately 86%, 91%, and 70%, respectively, relative to the acid-deteriorated control. This mix also maintained a surface pH ≥ 8.5, indicating strong buffering capacity under acidic conditions. At the microstructural level, p-GO nanosheets facilitated the formation of modified graphene oxide (mGO) hydration phases that filled voids, sealed micro-cracks, and densified the interfacial transition zone (ITZ), forming a chemically resilient barrier against ion ingress. These effects were reinforced by refined pore structure, increased C–S–H gel development, and proposed covalent interactions involving Si–O–GO and Al–O–GO linkages, which collectively improved microstructural compactness. As a result, degradation depth and porosity were reduced by ∼92% and ∼ 84%, respectively, relative to the acid-exposed control. This study presents new insights into the multifunctional nano-reinforcement mechanisms of p-GO in cementitious systems and establishes GO-TBNCCs as a promising class of durable, sustainable materials for infrastructure exposed to aggressive environments such as sewer systems. • Polyfunctionalised graphene oxide (p-GO) colloid enhanced dispersion, hydration, and microstructural densification. • Optimal mix (20F40GB639GO) achieved ∼123% strength gain with reduced losses, porosity, and degradation depth. • mGO-hydration phases and C–S–H gels enhance crack bridging, ITZ densification, and resistance to acid ingress. • .Synergistic pGO–GGBFS–FA interactions improve durability from nano- to micro-scale in aggressive environments.