Thermal Conductivity of Fibre Reinforced Porous Calcium Silicate Hydrate-based Composites

Abstract

Steady-state thermal conductivity measurements of the cellulose fibre reinforced calcium silicate insulation boards were carried out. After exclusion of the effects caused by the enthalpy flow and the possible non-linear moisture content distribution the effective thermal conductivity-moisture content relations were determined from the measured apparent thermal conductivity values. The achieved moisture dependences of the thermal conductivity have had in the first approximation the character of a bilinear function for all measured types of calcium silicates. The material structure-based model capturing the essential features of the capillary pressure - strain and the stress - crack width relationships and coupling the water sorption and mechanical behaviour was applied for an explanation of determined courses of the moisture dependent thermal conductivities.