Utilizing Polypropylene Fiber in Sustainable Structural Concrete Mixtures

Polypropylene fiber reinforced concrete (PFRC) is becoming more popular for structural purposes due to its durability, electrical resistivity, and mechanical properties. In this study, the influence of polypropylene fiber on the mechanical properties and ultrasonic pulse velocity (UPV) of fiber reinforced concrete (FRC) were determined. Six different fiber volume fractions of polypropylene were considered in the experimental investigation with varying water–cement ratios and curing conditions. Non-destructive testing methods were utilized to determine the UPV of the PFRC. Available equations in literature for predicting the RFC’s compressive strength based on UPV values were selected. However, the computed values did not show good agreement with the compressive strengths obtained from the compression testing machine. It was confirmed that polypropylene fibers alter the propagation of UPV, and as a result, the existing equations do not accurately predict the compressive strength for PFRC. Therefore, a practical equation is proposed to accurately evaluate the compressive strength of PFRC with regard to UPV.