Natural fibers as reinforcement of mortar and concrete: a systematic review from central and south American regions

Abstract

This study examines recent research on mortar and concrete reinforced with natural fibers (NF). NF are a sustainable, eco-friendly alternative to conventional fibers, offering a way to reduce waste that would otherwise end up in landfills. The diversity of environments across continents provides a wide range of NF to study, and examining representative regions advances the knowledge obtained by enabling comparisons among varied global conditions. A key challenge with NF is their susceptibility to aggressive environments, thus necessitating pretreatment, with alkaline treatment being the most common method to enhance NF properties. As it has been reported, the workability of concrete and mortar decreases as NF content increases, yet this can be mitigated by adding more water or superplasticizers. Despite their benefits, it is advised not to use more than 0.5 % vol. of NF, as higher amounts typically lead to a reduction in the mechanical properties of the result. The durability and microstructure of NF-reinforced materials varies in accordance with test conditions and fiber types, moreover, testing in saline or accelerated aging environments often yields poor results. Further research on NF durability, particularly regarding dry-wet cycles and chloride penetration, is crucial. Environmental analyses show that concrete with NF offers lower energy requirements and reduces carbon footprints. Given the global complexities of NF, systematic studies in other regions are needed for comparative analysis. Nonetheless, using NF as reinforcement helps reduce agricultural waste by diverting it from landfills, aligning with circular economy principles, and promoting sustainability.