Effect of graphene oxide on the deterioration of cement pastes exposed to citric and sulfuric acids

Acid-induced deterioration reduces the service life of concrete and requires high maintenance costs. This study examined the deterioration of graphene oxide (GO)-modified cement pastes exposed to 1 M citric acid (C₆H₈O₇) and 1 M sulfuric acid (H₂SO₄) environments for two weeks. Changes in the physical and chemical properties of the binder matrix were determined by the assessment of fresh and hardened properties, and a detailed microstructural analysis involving SEM-EDS, XRD, FT-IR and TGA-DTG. The formation of a thick earlandite- and gypsum-like salt was observed in the altered areas of all samples after citric acid and sulfuric acid attacks, respectively. A consistent reduction in the mass loss and sectional area loss was recorded as the GO content increased from 0 to 0.09 wt% under both acid environments, also supported by microstructural analysis and micro-hardness results. The decline in deterioration under these acid environments was associated with the increased resistance provided by GO that reduced the penetration of aggressive chemical species into the matrix. Determination of an optimum GO content to achieve a balance between reaction mechanisms, fresh properties and durability is critical for improved performance in the long-term.