Research of physical properties of straw for building panels

Abstract

The development of new thermal insulation materials needs to evaluate properties and structure of raw materials, technological factors that make influence on the thermal conductivity of material. One of the most promising raw materials for production of insulation material is straw. The use of natural fibres as insulation is closely linked to the ecological building sector, where selection of materials is based on factors including recyclable, renewable raw materials and low resource production techniques. In current work results of research on structure, thermal conductivity, water vapour permeability and short term water immersion of triticale straw for production of thermal insulating straw panels are presented. Straw panels withdifferent densitywere prepared for thermal conductivity measurement. It was determined that lowest thermal conductivity of straw is reached when straw density ranges from 80kg/m3 to 120 kg/m3. It was found that the macrostructure that changes with density increase has the great effect on thermal conductivity of materials. At the density range of 120-190 kg/m3 increase of thermal conductivity values are observed. Water vapour permeabilitywas analysed at the density ranges from 80 kg/m3 to 156 kg/m3. Vapour permeability values grew with density increase from 2 to 2.5. Short term water absorption was evaluated by two parameters - as water absorption coefficient due to capillary action and short term water absorption by partial immersion. Water absorption coefficient shows sudden mass increase within the first 10 minutes and subsequent slow mass increase. Short term water absorption values show significant weight increase during 48 hours, which reaches 100 percent by mass.