Influence of the instability of the double punch test on the post-crack response of fiber-reinforced concrete

Abstract

The characterization of the post-crack behavior of fiber-reinforced concrete (FRC) is essential in order to properly design and apply this composite. Although beam tests (3 and 4 points) are standardized for this purpose, a simpler methodology is necessary to be designated as a regular quality control method. In this context, the research presented in this paper focuses on the evaluation of the double punch test (DPT) as an alternative method to control the mechanical behavior of FRC. Tests were performed in open and closed-loop test machines to verify if the instabilities caused after the matrix cracks compromise the determination of residual strength. Results showed that when open-loop test machines are employed, post-crack instability is greater. However, it does not influence the determination of residual strength negatively. Therefore, the DPT performed in open-loop test machines may be used for the routine analysis and characterization of FRC.