Bio-based construction panels for low carbon development

Abstract

Over the last years there has been an increase in demand for construction materials that fulfil the high-level energy efficiency requirements while ensuring reduced impact on environment compared to the traditionally used materials. The hemp-lime concrete as a self-bearing thermal insulation material with low thermal conductivity and neutral CO2 emissions is one of such materials that can ensure it. However due to its limited strength the use of this material is problematic in projects of industrial scale. Magnesium oxychloride binders are of considerably higher strength level and better bio-compatibility compared to the lime-based binders, hence in this research the former were used in combination with a hemp filler to produce composite materials to be used in production of construction panels for industrial scale. These panels consist of an outer and inner border layer and a middle thermal insulation layer, that can be provided by magnesium-hemp concrete with varied amount of the binder added. To evaluate impact on environment of such panels, the Life cycle assessment was performed, analyzing amount of CO2 produced by them and comparing it to the traditionally used materials with similar thermal transmittance properties. Results of the research showcase that the magnesium-hemp concrete can be used in production of bio-based construction panels because strength of their outer layers can reach up to 1.2 MPa at 450 kg/m3 density and that of the inner layer – 0.06 W/m·K at 200 kg/m3 density. It was proved in the research that the magnesium-hemp panel represents reduced impact on environment because a panel, 370 mm thick, that ensures the U value of 0.18, emits 12.7 kg/CO2 eq. m2, that is 5 times less compared to the traditionally used materials.