Short rotation coppice trees in contaminated sites: A study of wood characteristics for bio-concrete applications

Short rotation coppice trees, including poplar ( Populus spp.), willow ( Salix spp.), and black locust ( Robinia pseudoacacia L.), present an exciting opportunity for sustainable biomass production, while also contributing to soil remediation efforts. Harnessing this biomass in construction concrete supports and aligns perfectly with the EU's ambitious 2030 emission targets. Therefore, this study evaluates metal and mineral accumulation and investigates the potential of utilizing wood aggregates as alternative biomass fillers in concrete. Consequently, the cell wall composition, sorption characteristics, metal impurity concentrations, pH, pH buffering capacity, and mineral and ash content of wood and bark obtained from an industrially contaminated site were analysed. The findings reveal that the biomass from the contaminated site had higher mineral content than samples from sawmills. The bark—particularly from black locust—displayed a notable ash content of 8.3 %, largely due to sizeable presence of calcium minerals. In contrast, the wood's ash content was 0.76 %, approximately 1.9 times higher than sawmill wood (0.4 %). Subtle cell wall composition variations were also observed compared to sawmill wood. Overall, the sorption properties, particularly concerning moisture retention, were reflective of lignin content. When evaluating concrete viability, the pH buffering capacity of all examined wood samples was lower, while the bark samples boasted a higher capacity compared to the reference hemp shives. Notably, poplar bark from the contaminated site achieved an average buffering capacity that surpassed the reference bark by 10.9 %. Poplar wood aggregate concretes achieved 0.16 MPa strength and 373 kg/m 3 density, showing optimization potential. • pH buffering capacity and moisture sorption of contaminated trees' wood/bark • Bark retains more moisture than wood, largely due to higher lignin content. • The presence of high levels of calcium in bark causes less acidic pH than wood. • Wood K minerals form volatile compounds during combustion, unlike Ca, which is stable above 450 °C. • Poplar wood aggregates (3–7 mm) show promise in concrete (0.16 MPa, 373 kg/m 3 ).