Evaluating the performance of cement-reduced concrete using graphene oxide: Synergistic effects on mechanical properties

• Addition of Graphene Oxide (GO) is effectively improved the strength gain of Fly ash (FA) concrete. • Selecting the appropriate superplasticiser (PS) content is crucial to optimise the mechanical properties of GO-FA concrete. • Pore structure of FA concrete is effectively refined by adding GO. Concrete is the most widely used material in the construction industry. However, the cement used in its production raises concerns due to high energy consumption and carbon emissions. This study investigates the potential of using Graphene Oxide (GO) to enhance concrete's performance while replacing a considerable percentage of cement with industrial byproduct, Fly ash (FA). The primary objective is to reduce cement demand while achieving similar or enhanced concrete properties. The study examines the effect of FA replacements (10 %, 20 %, and 30 %) at a constant GO dosage on concrete's workability, compressive strength, indirect tensile strength, flexural strength, and elastic modulus. Additionally, different superplasticiser dosages were examined to maximise the benefits of GO through optimal dispersion. Mechanical properties were evaluated over 90 days curing period, and microstructural analysis was conducted using scanning electron microscopy (SEM). The results indicated that increasing FA content improves the workability of GO-added concrete, counteracting the workability reduction typically caused by GO. At 28 days, the GO-FA mix with 30 % FA replacement achieved mechanical properties comparable to conventional concrete, with slight enhancements of 6 %, 2 %, 3 %, and 4 % in compressive strength, indirect tensile strength, flexural strength, and elastic modulus, respectively. In contrast, FA-only mixes exhibited a 13 % reduction in compressive strength. SEM analysis confirmed that GO improved the microstructure, contributing to this enhanced mechanical performance in GO-FA concrete. This innovative approach demonstrates the feasibility of reducing cement consumption in concrete production without compromising its mechanical performance.