Optimisation of vibrocompaction process for wood-based concrete blocks

In the aim of enhancing the reuse potential of poplar sawdust stemming from the transformation of wood into particleboard for woodworking purposes, wood-reinforced concrete mix designs are optimised to obtain composites in compliance with French standard NF EN 771-3/CN. Two criteria are assessed herein for structural elements, namely dimensional tolerance and mechanical strength (7-day levels above 6 MPa). Wood aggregates are introduced by means of a volumetric substitution for sand. Easily demoldable concrete blocks have been produced by means of vibrocompaction. A high vibration frequency is coupled with a compaction process in order to generate semi-dry cylindrical concrete blocks (100 mm in diameter, 200 mm high). The addition of wood into the cementitious composite exerts a noticeable influence on its workability, as well as on its thermophysical and mechanical behaviour. Wood alters how the cementitious composite is hydrated and has an impact on its mechanical strength in compression, which drops considerably with an increase in sawdust content. A 50% rate of substituting poplar sawdust for sand was chosen for testing purposes. This concrete composition actually yields mechanical strength values similar to that of the reference concrete used to manufacture masonry blocks.