Bio-based cementitious composites reinforced with natural fibers derived from Cedrus libani A.Rich. acicular leaf: Extraction, microstructural characterization, and mechanical performance after thermal exposure

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Şamdan F., ŞAMDAN C., CANBAZ M.

Challenge Journal of Concrete Research Letters, cilt.17, sa.2, ss.162-176, 2026 (Scopus, TRDizin)

Özet

This study investigates the physical and mechanical performance of bio-based cementitious composites produced with natural fibers obtained from dried, fallen acicular leaf of Cedrus libani A.Rich. The fibers underwent a multi-stage pre-treatment prior to composite production, including hot water extraction, alkaline treatment (NaOH), and Ca(OH)₂ mineralization. Changes in surface morphology and chemical composition were confirmed by SEM and EDS analyses, and significant calcium enrichment and increased roughness were observed on the fiber surface after mineralization. Specimens produced with aggregate-and additive-free mixtures were exposed to temperatures of 20, 200, and 400 °C for 3 hours at the end of the curing periods. Unit volume weight, ultrasonic pulse velocity, compressive, flexural, and splitting tensile strengths were determined, and the dynamic modulus of elasticity was calculated. The results showed that limited losses in mechanical properties occurred up to 200 °C, while more significant reductions in strength and stiffness occurred at 400 °C due to microcrack formation and weakening of the fiber-matrix interface. It was determined that mixtures with a high fiber/cement ratio partially limit crack progression and reduce strength loss in certain temperature ranges. The findings reveal the mechanical properties of Cedrus libani acicular leaf fibers as reinforcement in cementitious composites after thermal exposure.