Lalla, ISmailZahraoui, Mohamed IhabDERBAL, Ahlem2025-07-102025-07-102025http://dspace.univ-temouchent.edu.dz/handle/123456789/6568Mortar is a cement-based material widely used in civil engineering. In certain use conditions, especially when exposed to high temperatures (such as fires or extreme environments), its physical and mechanical properties may be significantly affected. Therefore the present experimental study aims to analyze the effect of temperature on the behavior of mortars reinforced with natural plant fibers, particularly those extracted from date palm and marine algae. Special attention was also given to the incorporation of natural perlite from Hammam Boughrara (Maghnia), used as a partial replacement for sand, to improve the thermo-physical behavior of the mortar and lighten its structure. This research focuses on the influence of these natural components in various mortar formulations, using a constant water/binder ratio and exposing them to increasing temperatures of 200, 400, and 600°C. The plant fibers were pre-treated with an alkaline solution (NaOH) to enhance their durability and bonding with the cement matrix. Several tests were conducted on both fresh(workability, entrained air) and hardened mortars (flexural and compressive strength, capillary absorption, thermal conductivity, ultrasound). The results show that the addition of plant fibers and perlite significantly influences the thermo-mechanical behavior of the studied mortars. At room temperature, their performance is improved, but at higher temperatures, the thermal degradation of the fibers becomes a limiting factor. This study highlights the potential of plant fibers and perlite as eco-friendly and efficient alternatives in mortar formulation, while emphasizing the importance of optimal dosage and appropriate treatments to ensure thermal stability.frMortiers, Effet de la température, Fibres végétales, Palmier dattier, Algues, Perlite, Traitement alcalin.Mortars, Temperature effect, Plant fibers, Date palm, Algae, Perlite, Alkaline treatment.Thesis