Lightweight Composites Based on Technical Hemp Hurds in Construction Industry

Abstract

This article discusses about the possibility of using technical hemp as a source of natural fibres for purpose of construction. The technical hemp (Cannabis Sativa) is the source of two types of fibres; bast fibres (used mainly in the paper and textile industries) and woody fibres - hurds. In recent decades hemp hurds have experienced a renaissance in use in the construction industry. This material is waste resulting from the processing of hemp stem on bast fibres. For the purposes of construction, it has potential thanks to their exceptional thermal insulation, antiseptic, acoustic and mechanical properties. One of the aspects of using hemp products in building industry is its environmentally friendly properties in comparison to the conventional materials (such as insulating materials with polymer matrix or based on mineral wool). Due to the low density and high porosity of the hemp fibres, the combination of hemp and binder creates high-quality products such as hemp concrete, fibre boards and lightweight composites. In this paper, the physical and mechanical properties of lightweight composites based on pre-treated hemp hurds and alternative binder MgO-cement are studied after their hardening in indoor condition for 28 days. The results of the parameters (density, density changes after thermal stress, water absorbability, thermal conductivity coefficient, compressive and tensile strength) of composites presented with emphasis on their usage as thermal insulation material show some differences which are determined by properties of modified filler (hemp material) as well as by properties of filler/binder interface.