@article{HerzMuscatStruebbe2025, author = {Herz, Jonas and Muscat, Dirk and Str{\"u}bbe, Nicole}, title = {The Influence of Fillers on the Reinforcement Capabilities of Polypropylene Based Mono-Material and Core-Shell Fibers in Concrete, a Comparison}, series = {Polymers}, volume = {17}, journal = {Polymers}, number = {13}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/polym17131781}, pages = {24}, year = {2025}, abstract = {Noncorrosive concrete reinforcement, such as polymer fibers, is needed to overcome the current issues caused by corroded steel reinforcements. Fibers made of polypropylene show a low bonding behavior in concrete. Fillers can help to overcome this issue but often lead to reduced mechanical properties. Core-shell fibers, which split the mechanical properties and the bonding behavior between the core and the shell component, could be a solution. This study investigates mono-material and core-shell fibers produced with calcium carbonate and bentonite fillers and compares their behavior in tensile tests, density measurements, contact angle measurements, topography measurements, single fiber pull-out tests, reflected light microscopy, and thermogravimetric analysis. The fillers caused an increased drawability, resulting in higher mechanical properties. Further, in the core-shell fibers, the calcium carbonate increased the surface roughness, which led to a better anchoring of the fiber in concrete, which was also visible in the deformation during pull-out observed in reflected light microscopy pictures. The thermogravimetric analysis showed a delay in onset of degradation for fibers containing bentonite.}, language = {en} } @article{HerzSchusserMuscatetal.2025, author = {Herz, Jonas and Schusser, Verena and Muscat, Dirk and Str{\"u}bbe, Nicole}, title = {Cold-Drawn Wood-Filled Polybutylene Succinate Macro-Fibers as a Reinforcing Material for Concrete}, series = {Polymers}, volume = {17}, journal = {Polymers}, number = {3}, publisher = {MDPI}, address = {Basel}, doi = {https://doi.org/10.3390/polym17030403}, pages = {21}, year = {2025}, abstract = {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.}, language = {en} } @article{SigruenerMuscatStruebbe2021, author = {Sigr{\"u}ner, Michael and Muscat, Dirk and Str{\"u}bbe, Nicole}, title = {Investigation on pull-out behavior and interface critical parameters of polymer fibers embedded in concrete and their correlation with particular fiber properties}, series = {Journal of Applied Polymer Science}, volume = {138}, journal = {Journal of Applied Polymer Science}, number = {28}, pages = {50745}, year = {2021}, abstract = {A crucial problem in concrete engineering is the corrosion of steel reinforcements. Polymer fibers as alternative reinforcement material can prevent corrosion; however, high adhesion to concrete and good fiber mechanics are necessary for polymers to be considered as an alternative reinforcement. This study tested different thermoplastic polymer materials to evaluate their level of adhesion to concrete. The adhesion properties of different self-drawn polymer fibers were analyzed by extracting the fibers from concrete using single fiber pull-out test (SFPT). To determine the adhesion mechanism, different polymer properties were analyzed and correlated to SFPT. Strong evidence was found that the fibers mechanical properties correlate with SFPT. Roughening the fiber surface increases the SFPT results significantly. While highly polar materials can support the adhesion process, a clear correlation could not be found. This study identifies high stiffness and roughness as the crucial properties of polymer fibers used in concrete engineering. If these factors can be engineered into the fiber, polymer fibers can present an alternative to steel in concrete reinforcement.}, language = {en} }