Physical and mechanical properties of unfired clay bricks with saw palmetto fibers additive as a construction material

Abstract

With the aim of obtaining construction bricks with improved properties, this paper provides a design of unfired clay bricks based on extracted clay from Oulad Azam village in the region of Taounate in Morocco and fibers additive of saw palmetto (Chamaerops Humilis). The main objective is to study the influence of saw palmetto fibers dosage on the physical and mechanical properties of unfired bricks. First, the soil underwent a treatment process starting with the elimination of organic matter, drying for 24 h and retention of the 0/200 µm fraction by sieving after grinding the soil. Saw palmetto additive was incorporated in the form of fibers of sizes ranging from one to four centimeters produced manually using a scissor by cutting the leaves and rejecting the stem, considering a variation of the percentage by weight of the additive (0 %; 1 %; 5 %; 7 %; 10 % & 12 %). The measurements of the bulk density according to NM EN 772–16 showed that the bricks obtained are light since their bulk density does not reach 2.75 g/cm3 as the limit value prescribed by the aforementioned standard. The results of the compressive strength according to NM EN 772–1 showed a noticeable decrease as the percentage by weight of the additive exceeds 1 %, which is explaining by the fact that the dosage of 1 % provides a better consistency between the layers of clay, prevent deformation of the brick, causes homogeneity and uniforms distribution within the clay brick. On the contrary, the measurements of flexural strength according to NM EN 772–2 showed a notable decrease in bricks resistance following a direct increase in the dosage of saw palmetto additives. According to the German DIN 18945(2013–08) standard, a dosage of 12 % of the additive produces Earth Blocks Class 5(EB5), while bellow this dosage the bricks obtained are classified EB6 as a higher class prescribed by the aforementioned standard, that can be used in all types of earth construction. Hence, a positive impact on the local socio-economy and ecology of the region is envisioned thanks to the valorization of its natural resources.