Comparison between Direct Tension, Four-Point Flexure, and Simplified Double-Punch Tests for UHPC Tensile Behavior

Abstract

As ultra-high-performance concrete (UHPC) becomes more widely used, the need for good concrete tensile tests for fiber-reinforced concrete has become apparent. However, there is not yet one universally used test method. This research compares the results between standard direct tension, four-point flexure, and double-punch tests. Each test method was run on batches of UHPC made with two fiber types each at five different doses by percent volume, resulting in a testing matrix of 10 different mixes. The results of each test method were plotted to see how well different outcomes, such as peak strength and toughness, would reflect differences in fiber content. The results of the two indirect tension tests were then compared to the results of the direct tension test to see how well they correlated. Results showed that the average maximum stresses of each test method did not have good correlation but that measures of toughness or postcracking strength did have reliable correlation between the direct tension test and both of the simpler test methods.