Enhancing the mechanical and thermal insulation properties of clay-based construction materials with neutral carbon footprint through the use of Doum fibers

Abstract

The construction industry is currently experiencing robust global growth. With the advancement of technology, real estate development is evolving through the adoption of new strategies. The present study aims to identify the optimal formulation for unfired bricks made from clay and Doum fibers sourced from the Taounate region in Morocco. To achieve this, six brick samples were produced with varying amounts of Doum fibers (0 %, 1 %, 5 %, 7 %, 10 %, and 12 %), and their performance was assessed through tests for bulk density, linear shrinkage, compressive strength, and thermal conductivity. The results indicate that the resulting bricks are lightweight, with a bulk density not exceeding 1.75 g/cm3, in accordance with the NM EN 772-16 standard. Furthermore, there was a notable reduction in linear shrinkage, reaching up to 80 %. The reference brick without fiber additions exhibited a shrinkage of 5.86 %, whereas the brick containing a high fiber content of 12 % demonstrated a linear shrinkage of 1.12 %. The strength of the brick decreases with increasing fiber content, but the thermal insulation properties improve significantly. Considering these variations, the optimal enhancement in thermal and mechanical performance was determined to be 41.5 % in terms of compressive strength and thermal conductivity, corresponding to a 10 % inclusion of Doum fibers. The optimal brick is classified as EB6 according to the German standard DIN 18945 (2013–08), with a thermal conductivity of 0.31 W/m.K and a compressive strength of 8.26 MPa, rendering it suitable for use in earth construction. This study also concludes that the production cost for the optimal brick is half that of the conventional bricks available in the building materials market. This holds promising implications for the future of harnessing local natural resources in the field of eco-construction, as it positively impacts the economy and environment of the region.