Sustainable reinforcement for resilient infrastructure: bamboo in geopolymer and OPC systems – mechanical and bond behavior

This study examines the mechanical performance and sustainability potential of bamboo-reinforced geopolymer concrete (GPC) compared with conventional ordinary Portland cement concrete (OPCC). A slag–fly ash-based, air-cured GPC mix (75:25 binder ratio) was activated using an aqueous solution containing calculated amounts of sodium silicate–sodium hydroxide solution and reinforced with treated bamboo (Biduru species). Bamboo culms were air-dried and coated with insecticide, elastomeric paint, and sand to enhance bond and durability. Mechanical tests on compressive, split-tensile, flexural, and bond behaviour were conducted following Indian Standards. GPC achieved higher compressive (39 MPa), split-tensile (2.97 MPa), and flexural (4.72 MPa) strengths than OPCC by 18%, 25%, and 13%, respectively. Treated bamboo-reinforced GPC beams reached 55% of the flexural capacity of steel-reinforced OPCC beams, with a 19% improvement in bond strength and a semi-ductile failure response. These results confirm bamboo’s viability as a renewable, low-carbon reinforcement for non-critical structural applications such as rural housing and sustainable infrastructure. While long-term durability under alkaline and environmental exposures warrants further study, the findings provide experimental evidence supporting the integration of bamboo reinforcement within GPC systems for eco-efficient, resilient construction.