Static and dynamic mechanical properties of eco-friendly polyvinyl alcohol fiber-reinforced ultra-high-strength concrete

An eco-friendly polyvinyl alcohol (PVA) fiber-reinforced ultra-high-strength concrete (PFR-UHSC) was designed and mixed to evaluate its static and dynamic mechanical properties in this study. A lower water-to-binder ratio of 0.22 and a superplasticizer were used to guarantee the performance of PFR-UHSC, while several industrial by-products were involved to reduce the negative environmental impact of concrete. Four volume fraction of PVA fibers (V-f=0, 0.5, 1.0, and 1.5%) were included in the experiment and steel fiber-reinforced ultra-high-strength concrete (SFR-UHSC) with V-f=1.0% was also tested as a comparison. Experiment results show that although less ductile than SFR-UHSC, PFR-UHSC exhibits relatively good ductility, toughness, and deformability under static loadings. Namely, splitting tensile and flexural strengths as well as flexural toughness of PFR-UHSC are significantly improved by the incorporation of PVA fibers while no obvious variation is viewed for Young's modulus. And even, the compressive strength of PFR-UHSC decreases slightly with the increasing PVA fiber dosage. When subjected to dynamic loadings with lower strain rates, PFR-UHSC displays a better performance than SFR-UHSC in terms of failure patterns, while a reverse behavior is observed for high strain rate. Affected by introduction of PVA fiber, the enhancement of strain rate for compressive strength of PFR-UHSC is lower than that for ordinary concrete but higher than that for SFR-UHSC. Besides, although having a slightly lower compressive toughness, the energy absorption capacity of PFR-UHSC is similar to that of SFR-UHSC.