Use of Waste Raw Materials in the Form of Hemp Shives and Waste Sheep Wool to Produce Composites Dedicated to Thermal Insulation

Abstract

The aim of this research was to develop composites dedicated to thermal insulation, developed on the basis of natural raw materials. The composites consisted of mixture of lime, cement, water, and two biodegradable materials: a local mountain sheep wool treated as troublesome waste and hemp shives obtained by processing decorticated hemp straw of the Białobrzeskie variety. On a laboratory scale, blocks were produced with varying percentages of shives with a fraction of 10 and 30 mm. Sheep wool used was in two ways: (1) mixed in the mass or (2) arranged in a layer between lime. The basic parameter – thermal conductivity of the composites was determined. The research showed that making a composite of lime with hemp shives decreased the thermal conductivity coefficient of the material. The addition of hemp shives reduced the thermal conductivity coefficient by an average of 36% and 45%, when using shives crushed into 10 mm fractions or 30 mm fractions, respectively. The addition of 20% and 40% sheep wool decreased the λ coefficient by approximately 40%. The λ coefficient of the composite formed using hemp shives and wool is 0.0738 W/mK. The proposed composites might be a good alternative to commonly used thermal insulation materials.

Keywords

• Hemp shives
• wool
• insulating material
• waste management
• thermal resistance
• lime