Boudissa samah nihedAttou WafaaABDELHADI Houari2026-10-012026-10-012026https://dspace.univ-temouchent.edu.dz/handle/123456789/7712In the context of sustainable construction and the valorization of bio-based materials, this study investigates the use of cork waste as lightweight aggregates in plaster mortars. The main objective is to evaluate the influence of different pre-treatments applied to natural cork aggregates on the physical, mechanical, thermal, and acoustic properties of plaster mortars, with the aim of developing a more efficient and environmentally friendly building material. Three pre-treatment methods were studied: hot-water treatment (T1), hornification treatment (T2), and lime treatment (T3). Cork aggregates were used as a partial replacement for sand at different substitution rates (0%, 25%, 50%, 75%, and 100%). Several tests were carried out in both fresh and hardened states, including workability, bulk density, surface hardness, ultrasonic pulse velocity, flexural and compressive strength, thermal conductivity, water absorption, porosity, durability under wetting–drying cycles, and acoustic insulation. The results showed that the incorporation of cork leads to a progressive decrease in mortar density, producing lighter materials. It also significantly improves thermal insulation due to the low thermal conductivity of cork. However, increasing the cork content results in higher water absorption and porosity, accompanied by a reduction in mechanical strength. The comparative analysis revealed that the hornification treatment (T2) provides the best compromise between mechanical performance, durability, and fresh-state behavior, whereas the lime treatment (T3) offers the best thermal insulation performance. Acoustic tests also highlighted the potential of cork to improve sound insulation at specific frequencies. This study confirms that plaster–cork mortars represent a promising eco-friendly solution for the construction sector. The choice of cork pre-treatment makes it possible to tailor the material properties according to the requirements of the intended application.frPlaster mortarnatural corkbio-based aggregatespre-treatmentmechanical propertiesthermal insulationacoustic insulationdurability.Thesis