Cold-Drawn Wood-Filled Polybutylene Succinate Macro-Fibers as a Reinforcing Material for Concrete

The corrosive behavior of steel reinforcements causes issues in the concrete industry. To overcome this issue, alternative noncorrosive reinforcements such as polymer fibers could be used. However, as environmental protection becomes more important, sustainability must also be considered in the solution. An alternative to polymers based on raw oil is bio-based polymers. This study investigates the suitability of polymer fibers produced from polybutylene succinate together with cellulose and wood fillers as concrete reinforcements. Different mixtures of polybutylene succinate, cellulose, and wood fillers were created, and fibers were produced using a multiple drawing process. The fibers were tested using tensile tests, a single-fiber pull-out test, contact angle measurements, reflected light microscopy, density measurements, and thermogravimetric analysis. The fillers were shown to decrease the mechanical properties as the particle size and filler amount increased, resulting in a reduction in Young's modulus and tensile strength of 55% and 70%, respectively, while adhesion to concrete increased with particle size from 0.31 ± 0.02 N/mm² without filler to 0.90 ± 0.10 N/mm² for the best-performing material combination. Reflected light microscopy images show changes in the fiber surface before and after pull-out. The fiber density decreased from 1.26 ± 0.05 g/cm³ to 0.91 ± 0.04 g/cm³ with an increasing filler amount and particle size for a compound with 10 weight percent of wood filler 1. The fiber thermal stability decreased slightly with the addition of filler. The greatest effect was a reduction in the temperature to ≈58 °C at 1% weight loss when 10 weight percent of wood was added. This study proves the possibility of using bio-based materials as concrete reinforcements.