Open Collections

Schild, Anna Helena

University of British Columbia

Sustainable wood manufacturing practices increasingly include the recycling and reuse of waste wood. To avoid cross-contamination of potentially harmful treatments found in the wood industry, sorting is necessary. Visual sorting approaches were assessed, and it was found that they cannot reliably sort waste wood without exceeding existing heavy metal limits. Consequently, near-infrared hyperspectral imaging was used to identify wood waste type in three scenarios: (1) distinguishing new wood composites, (2) differentiating composites obtained from a landfill, and (3) distinguishing waste wood composites in a simulated waste wood stream. A partial least square discriminant analysis was employed, and it was found that accuracies reduced with each scenario. Nonetheless, all models were able to accurately predict at least 80% of the samples. To assess recyclability of wood composites (plywood, ACQ treated plywood, oriented strand board, particleboard, and melamine coated particleboard) in cement-bonded wood composites, hydration tests were conducted. The exothermic curing reaction of cement is inhibited when mixed with wood particles and the temperature reduction can be used to assess compatibility of wood with cement. These hydration tests found all wood composite types compatible with cement. However, the temperature curve of melamine coated and uncoated particleboard particles was missing a second temperature peak. Preliminary boards were manufactured and found to be very brittle, so it was concluded that the absence of a second temperature peak inhibits compatibility. Hydration tests should only be used to assess initial compatibility when a second peak is present and not be used to predict overall properties. Plywood, treated plywood and oriented strand board were subsequently used to manufacture cement-bonded wood composites. Their effect on density, modulus of elasticity (MOE), modulus of rupture (MOR), thickness swelling, water absorption and thermal conductivity on cement-bonded wood composites was evaluated along with that of particle size fraction and the use of an accelerator. The MOE and MOR values were smaller than expected due to a poor interface bond between the recycled wood particles and cement. However, the thermal conductivity of the cement-bonded panels met the minimum requirements. It is recommended that future studies explore how the interface bond could be improved.

Text

2024-08-14

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/88937

Forestry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/