Control of the ultra-high performance fibre Reiforced concrete (UHPFRC) concerning to postcracking performance

UHPFRC presents great advantages. However, there are some drawbacks concerning to quality control process: Non-uniform fibre distribution (content/orientation) and variation of post-cracking performance. Regarding the first, the high number of fibres complicates the homogenization of the mix. On the other hand, the toughness control, which depends on the content of fibres incorporated, as the conventional process described by the ASTM standard (beam test), is labour demanding and requires large specimens to be tested. Besides, this test is not suitable to be performed using specimens prepared with cores extracted from the structure and the variability of the result is high. In order to minimize drawbacks, an experimental study is presented analysing the suitability of using the inductive method and the Barcelona test to control UHPFRC. In that sense, six UHPFRC are analysed. The results of the inductive method are used to know the real fibre contents in the mixes and how this parameter is related to the residual strength of the material. The experimental results are statistically analysed and a correlation equation is obtained to determine the UHPFRC residual strength class using only the results from the Barcelona test. The last proves to be a feasible alternative to the beam test.