Development of Wood-Crete from Hardwood and Softwood Sawdust

Abstract

Wood-crete, a new building material has previously been developed from sawdust, inorganic binder and addition of waste paper, finding its use mainly for wall panelling or other non- and semi-structural applications with good thermal insulating properties. In this study, the properties of wood-crete were investigated based on the type of wood sawdust – hardwood (beech and oak) and softwood (pine and cedar). The results showed that (1) the compressive strength of wood-crete was closely related to the wood species, with the compressive strength of 3.93MPa being for hardwood wood-crete compared to 1.37MPa and 0.26MPa of wood-crete from softwood and mixed wood respectively; (2) wood-crete from hardwood sawdust had a higher density than those made from softwood sawdust and mixed wood; (3) particle size had a significant influence on the strength properties and density of wood-crete with wood-crete made from 1mm particle size recording a higher compressive strength and density compared to 2mm and 3mm particle size. The optimum size for wood-crete was dependent on the wood species; (4) thermal conductivity of wood-crete was closely related to the chemical composition of various wood species, with softwood wood-crete having about 20% lower thermal conductivity compared to hardwood wood-crete; (5) a ratio of 1:2 of sawdust to binder was found advisable for the production of wood-crete for various wood species and particle sizes investigated. The compressive strength of wood-crete made from sawdust of both softwood and hardwood was similar to or higher than that of hempcrete, indicating their suitability for wall panelling or other non- and semi-structural applications. The results of this study provide an important foundation for choosing what wood species, particle sizes and combinations of sawdust to be used for the production of wood-crete.