Cementitious materials under uniaxial loads

The failure of cement-based materials is associated to a development of a damaged zone in the form of a more or less large region of microcracking. The development and the evolution of the damaged zone has a fundamental importance for defining the mechanical response in terms of both structural behavior and peak strength. For geometrically similar specimens under uniaxial tension of different sizes, this paper presents and discusses experimental evidence from interferometric measurements of the damaged zone development. The cement based materials had an aggregate/binder ratio of 2, a microsilica/binder ratio of 0.1 and a water binder ratio of 0.22. Specimens made with (2% by volume) and without steel reinforcing microfibers were considered. It is shown that the size effects appear reduced in the fiber-reinforced materials.