Experimental research on recycling of waste timber from construction: a case study

Abstract The construction industry generates significant timber waste, particularly from formwork systems, posing environmental and economic challenges. To promote resource recycling and sustainable construction, this study investigates the feasibility of utilizing recycled composite wood joists, fabricated from construction waste timber, polypropylene, polyester thread, and fibre composite bands, as the secondary joists in concrete formwork systems. Through theoretical analysis and on-site experiments, the load-bearing performance of the composite joists was evaluated under equivalent loads corresponding to concrete slabs of varying thicknesses. The results demonstrated that the deflection trends of the joists aligned closely with theoretical predictions, with a maximum deflection of 5.65 mm recorded under 4th load mode. The composite joists met the deformation standards (≤4 mm) for slabs up to 200 mm thickness, which can meet the relevant specifications for formwork construction. The study concludes that the recycled composite wood joist is a viable, eco-friendly alternative for secondary joists in formwork systems, contributing to sustainable construction practices by repurposing construction waste.