Punch test for the assessment of fracture energy on concrete mixed to natural plant fibers

Ductility of a material that collapses because of the propagation of cracks depends on elastic properties of the material, on the fracture energy as well as on the structural dimensions. In this paper, we discuss the use of the punch tests for the assessment of both the tensile strength and the fracture energy of cylindrical concrete specimens with different volume content of natural fibers derived from a very common plant of Sicily (agave). For the validation of the experimental results a numerical simulation of the test was also carried out a FEA using models in which tensile strength and fracture energy value, obtained by punch test, are an input of the material so that the failure load P can be obtained. A good accordance between numerical and experimental data permits us to support the use of the Punch Test (PT) as a more attractive testing method for the evaluation of the mechanical proprieties of the materials. PT, in fact, is much simpler to perform than the split cylinder test method. Besides, the study shows the improvement of the post cracking behavior of concrete element reinforced by the use of natural and renewable fiber.