Relationships among compressive strength and UPV of concrete reinforced with different types of fibers.

This paper determines the effect of steel, glass, and nylon fibers on the compressive strength and ultrasonic pulse velocity (UPV) of fiber reinforced concrete. The influence of different fiber types, fiber volume fraction, and water to cement ratios on the compressive strength of fiber reinforced concrete was tested using the compression test machine (CTM) and ultrasonic pulse velocity tester. Experiments were carried out at different ages on more than 100 cylindrical specimens. A comparison between the experimental results and equations available in the literature for prediction of compressive strength in terms of UPV was conducted to better evaluate the accuracy of available methods, when the type and volume fraction of fibers change. A new empirical equation that accounts for the presence of different types of fibers and fiber volume fraction is proposed to better estimate the compressive strength of steel, glass, and nylon fiber reinforced concrete.