Chemical resistance of synthesized graphene-modified cement paste containing natural pozzolans to acid attack

Abstract

This research aims to evaluate the impact of pumice and zeolite as natural pozzolans in cement paste prepared by water-dispersed graphene synthesized from graphite and surfactant against an acid attack. Firstly, the optimal amount of dispersed graphene was derived. Then, several tests such as compressive strength, sorptivity, and microstructural examination such as X-ray diffraction (XRD), scanning electron microscope (SEM), and mercury intrusion porosimetry (MIP) were applied to investigate the single and synergic influence of supplementary cementitious materials (SCMs) at various age of curing. Finally, the chemical resistance of different mixtures under H2SO4 and HNO3 attack was evaluated by weight loss and loss of compressive strength, followed by a visual and microstructural examination of the degradation at different immersion times up to 22 weeks. According to the results, in graphene-containing mixtures, pumice and zeolite decreased compressive strength by 15.5% and 20.4% at an early age, respectively. However, based on the MIP and XRD results, this reduction was mitigated by improving pozzolanic reaction in the long term. Regarding weight loss and compressive strength loss from acid attack results, zeolite reduced these characteristics by 251.72 % and 239.4% compared to the reference paste, respectively.