Abstract: In wood structures, the elements subjected to bending stresses, such as the beams, present a fracture initiated in the tensile region, and under these conditions, the use of laminated composite materials is presented as an alternative solution in the form of repair or reinforcement. This research aimed to evaluate the influence of the use of carbon fibers laminated composites in tensile reinforcement in the direction parallel to grain of Pinus elliotti and Manilkara huberi wood species. The Viapol two-component epoxy adhesive was used in the lamination and fixation of the unidirectional carbon fiber in the wood species. Ten specimens with no defects (reference) and 10 specimens were prepared for each crack length (25 and 50mm) with and without the reinforcement (60mm × 50mm) by the laminated composite. The tensile tests were performed in accordance with the requirements of the Brazilian standard. From the results of the statistical analysis, the use of the carbon fiber composite was able to restore the tensile strength of the cracked samples (partial or total) in relation to samples without defects, demonstrating the potential of the laminates in carbon fibers as an alternative solution in repair for both wood species.

Mechanical recycling is utilized to reuse waste and obtain other plastic products via the reprocessing of a material in industrial equipment. Natural fiber composites have become more popular in recent years; however, these composites' mechanical behavior remains less well-understood than single polymers’ behavior after recycling. Therefore, the objective of this work was to study the degradation of different sugarcane fibers/polypropylene composites using new grinding and injection processes and to evaluate the mechanical properties of these materials using analysis of variance (ANOVA). This work reveals the mechanical behaviors of recycled natural fiber composites that contain thermal stabilizer additives. Polypropylene composites reinforced with differently treated bagasse and straw fibers (10 and 20 wt%/PP) were obtained through melt mixing using a high-intensity thermokinetic mixer and were subsequently injected. The recycled composites exhibited decreased tensile strength relative to the original composites. However, when thermal stabilizers were added, the mechanical properties were maintained or increased, depending on the fiber and additive types.