High-strain rate compressive behavior of concrete with two different substituted recycled plastic aggregates: Experimental characterization and probabilistic modeling

This paper presents a pilot study on the characterization of the high-strain rate compressive behavior of a novel concrete with two different substituted recycled plastic aggregates. A reference mix with an average compressive strength of about 55MPa is considered. Recycled PolyEthylene Terephthalate (PET) powder and recycled mixed plastic (composed of PolyPropylene (PP) and PolyEthylene (PE)) granules were adopted to substitute fine and coarse aggregates. Two different substitution strategies are employed. In the first one, the PET powder is used to substitute the fine sand by volume. In the second one, the PET powder is used to substitute the fine sand while the recycled mixed plastic granules are used to substitute the coarse sand and fine coarse aggregates by volume (50% for PET powder and 50% for recycled mixed plastic granules). Four total replacement levels (5%, 10%, 20%, and 30%) by volume were considered. The fresh concrete properties (slump and density) and quasi-static compressive behavior, are investigated. The micro-scale characterization of the material using SEM scans provided a complete understanding of the observed macro-scale behavior. Tests were performed using conventional quasi-static loading with a compressive testing machine and high-strain rate tests with a Φ80-mm Split-Hopkinson Pressure Bar (SHPB) for strain rates up to 200s−1. The dynamic tests revealed the marked strain rate dependency, although specimens with large plastic volume substitution were more sensitive to the strain rate effect. A probabilistic data-driven model for the Dynamic Increase Factor (D I F) is also proposed based on the test data. Ultimately, this study indicates that the proposed material has a good high-strain rate compressive behavior and can be a promising material to be employed for protective techniques against impact and blast loads.