Influence of particle size of wood residues on the properties of mineral composites: part 2: gypsum-wood

Abstract Construction and demolition waste (CDW) wood can be incorporated into natural fibre composites, reducing environmental impacts, contributing to the development of more sustainable materials, products, and processes. The objective of this study was to evaluate the influence of particle size distribution of wood particles from construction and demolition residues (RCD) on the physical and mechanical properties of gypsum-wood composites. The wood particles (plywood, eucalyptus spp. and pinus spp.) were milled with hammers at different times and then characterised. Slow paste gypsum and water were also used. The gypsum-wood composites were produced with different binder/wood ratios in relation to water/gypsum set at 0.70 by mass. The study concludes that composites produced with the composition P1,2, either with plywood or pinus, or with the proportions 11% or 15% present the lowest hardened bulk density values, while the composites produced with the composition P1, or with eucalyptus, or with the proportion of 7.5% present greater flexural and compression strength.

摘要 建筑拆迁废料（Construction and Demolition Waste, CDW）木材可掺入天然纤维复合材料中，以降低环境影响，助力更可持续的材料、产品与工艺体系发展。本研究旨在评估建筑拆迁残渣（Residues of Construction and Demolition, RCD）来源木材颗粒的粒径分布对石膏-木材复合材料物理与力学性能的影响。研究所用木材颗粒取自胶合板、桉属（Eucalyptus spp.）与松属（Pinus spp.）材料，经不同时长锤磨处理后完成性能表征；同时采用缓凝石膏与水作为制备原料。本研究以质量计将水与石膏的比例固定为0.70，通过调整胶结剂与木材的配比制备系列石膏-木材复合材料。研究结果显示，采用P1,2配比制备的复合材料（无论使用胶合板还是松属木材），或采用11%、15%木材添加比例的复合材料，其硬化后的体积密度最低；而采用P1配比、桉属木材或7.5%木材添加比例制备的复合材料，则具备更优异的抗弯强度与抗压强度。