The mechanical behavior of thermally enhanced polypropylene concrete

Abstract

This article presents the investigation of the change of mechanical properties of reinforced and non-reinforced beams produced by using a constant amount of polypropylene (PP) instead of 50% of fine aggregates by volume as a result of exposure to high temperatures (170° C) for different periods (1, 3, and 5 h) of time. The thermal enhancement procedure is applied after the 28 days of curing period. Bending, shear and torsion tests were applied to the beams. In this study, torsional moment capacity, flexural, and shear strengths were evaluated according to the American Concrete Institute (ACI318-19) and Eurocode-2 standards. These theoretical values are compared with experimental results. The polypropylene aggregate, which is used instead of fine aggregates in reinforced or non-reinforced groups, caused a decrease in flexural and shear strength compared to the control samples. The ductile fracture tendency was increased with the exposure time of PP containing samples to high temperatures. The ultimate torsional moment and critical torsional moment are reduced except for the samples that have been heat-treated for 3 h in groups with and without reinforcement. The results show that none of the existing formulas according to the relevant standards is adequate for prediction of torsional moment, flexural and shear strengths of the beams with PP concrete.