Model for estimating the flexural performance of concrete reinforced with hooked end steel fibers using three-point bending tests

摘要

The behavior of fiber reinforced concrete (FRC) depends on the characteristics of both the concrete matrix and fibers. Previous studies have concluded that the number of hooked ends increases the contribution of steel fibers to the tensile performance of concrete. ACI 318 code, MC10 fib code and RILEM TC 162-TDF standard permit the use of steel fiber reinforced concrete (SFRC) for example, the minimum shear reinforcement made of deformed steel bars in flexure-controlled elements. Other investigations have demonstrated the suitable performance of SFRC in shear-controlled members and for seismic rehabilitation applications. It has become apparent that the adequate use of SFRC depends on the knowledge and prediction capabilities of its tensile performance. The results of three-point bending tests on SFRC beams using the test procedure established by the European standard EN-14651 are presented and discussed herein. Tests were executed with 20 standardized beams made of concrete with a nominal compressive strength of 24 MPa and hooked end steel fibers with an aspect ratio of 65 were applied. Variables were the fiber dosage (0, 20, 40, 60 kg/m(3)) and the number of fiber hooked ends (1, 1.5, and 2). A numerical model aimed at estimating the residual flexural tensile strength of the SFRC is developed. The proposed model was calibrated using a database of 256 tests, 20 from this study and the remaining 236 from 15 other studies.