Effect of Diss fibers on the mechanical and thermophysical characteristics of unfired clay bricks for use as construction material

This paper investigates the effect of incorporating Diss fibers on the physical, mechanical, and thermal performance of unfired clay bricks according to the Moroccan testing standards in the building sector. The used clay, extracted from Oulad Azam in the Taounate region in Morocco, was found of type illite with non-swelling characteristics and a dominant SiO2 content, 39.3%, following X-ray diffraction and fluorescence tests. Various Diss fibers proportions (0%, 1%, 3%, 5%, 7%, and 10%) were used. Collected findings showed an increase in linear shrinkage level reaching 0.73% at 10% additive content compared to 8% of reference samples. In addition, brick samples with 10% Diss fibers content reflected a bulk density of 1.17  g·cm⁻³ compared to reference samples of 1.26  g·cm⁻³. This reflects prominent lightweight properties. Mechanical conducted tests reflect a decrease in both compressive and flexural strength with Diss fibers reinforcement incorporation compared to reference values. Produced specimens were classified as Earth Blocks Class 4 (EB4), Earth Blocks Class 3 (EB3) and Earth Blocks Class 2 (EB2) according to their recorded compressive strength. It can be deduced that higher Diss fiber additive content produced good functioning brick samples, following Moroccan and international testing standards, with decreased shrinkage, a lightweight structures, more insulating properties and decreased compressive strength.