From waste to structure: predicting remaining mechanical properties of short-length waste (formwork) wood collected from construction sites: a non-destructive approach.

In the context of climate change, identifying alternative material sources has become essential, notably through the revalorization of waste materials. The construction industry is among the largest waste-generating sectors worldwide. A significant portion of this waste consists of formwork wood, which can account for up to one-third of construction-site waste. Due to demanding on-site conditions, formwork wood has a limited service life and is typically reused only one to four times before surface degradation compromises concrete quality. While the wood surface may no longer meet formwork requirements, it still retains structural integrity and significant reuse potential. This research investigates the remaining mechanical and structural properties of waste formwork wood to evaluate its suitability for structural reuse. Timber elements were collected from several construction sites across Belgium and assessed through visual grading as well as non-destructive and destructive testing methods. The experiments include ultrasonic pulse velocity measurements, compression tests, and four-point bending tests. Reusing reclaimed timber poses specific challenges, as each element differs in dimensions, material properties, and degree of deterioration, requiring adapted design and assessment strategies. This study explores the feasibility of employing short-length waste formwork wood in new structural applications by correlating non-destructive evaluation techniques with destructive test results, thereby contributing to more sustainable and resource-efficient construction practices.