Enhancing the fracture performance of cementitious composites through synergistic integration of graphene with polyolefin and polyvinyl alcohol fibres

Polyvinyl alcohol fibre (PVA) and polyolefin fibre (PO) are utilised in engineering cementitious composites (ECCs) due to their excellent crack-bridging capabilities, durability, ductility and energy absorption capacity. However, their combined effects on crack propagation mechanism, especially when combined with nano-reinforcement, remain underexplored. Recently, graphene nanoplatelets (GNPs) have emerged as promising nano-reinforcement in composite materials for enhancing the mechanical, thermal, and crack propagation resistance. Based on this premise, this study investigates the synergistic effects of GNPs combined with single and hybrid fibre reinforcement of PO-PVA at varying dosages (0.1 vol%, 0.3 vol%, and 0.6 vol%), aiming to improve the fracture performance of cementitious composites. Three-point bending tests were conducted using the AE technique to monitor crack initiation and propagation, allowing an in-depth analysis of crack evolution characteristics. By employing various AE parameters and advanced AE analysis methods, this research captures critical insights into microcracking events, fracture mechanisms, and failure modes in single and hybrid- PO-PVA fibre-reinforced composites containing GNPs. The research identifies the most beneficial concrete mix designs that significantly enhances interfacial bonding, microstructural integrity and fracture performance. Furthermore, the hybridisation of PVA-PO-GNPs leads to a notable shift in the dominant fracture mode towards shear cracks. This study findings are expected to provide novel insights into the optimization of FRC enhanced with nanomaterials, paving the way for innovative applications in advancing high-performance engineering structures with improved fracture resistance. • Cementitious composites reinforced with GNPs and polymer fibres • Synergistic effects of GNPs combined with single and hybrid PO-PVA fibres on the fracture behaviour of concrete • Monitoring of fracture evolution by AE method • Integration of GNPs with PO and PVA fibres shifts the main fracture mode towards shear cracking