Untreated date palm fibers for sustainable reinforcement of cement mortars: a comparative study on structural and render applications

The rising demand for low-cost, sustainable construction materials has intensified interest in repurposing agricultural waste fibers for cementitious applications. This study investigates the viability of using untreated date palm fibers (DPFs), a widely available byproduct in arid regions, as reinforcement in both structural and render mortars. Unlike previous studies, this work concurrently examines both mortar types under a unified experimental framework to evaluate the effects of fiber content (0.75–2.5% by volume) and length (5–35 mm) on key performance parameters. The testing program included flexural and compressive strength, water absorption, and scanning electron microscopy (SEM). Results revealed that untreated DPFs significantly enhance mechanical and physical properties when optimally dosed, particularly at 1.5% and 35 mm for structural mortars, and 0.75% and 10 mm for render mortars. SEM analysis confirmed good fiber-matrix interaction despite the absence of chemical treatment. These findings underscore the potential of untreated DPFs as a cost-effective, eco-efficient alternative to synthetic fibers, contributing to circular economy practices and directly supporting UN Sustainable Development Goals (SDGs).