Influence of concrete strength on crack development in SFRC members

Tension stiffening is still a matter of discussion into the scientific community; the study of this phenomenon is even more relevant in structural members where the total reinforcement consists of a proper combination of traditional rebars and steel fibers. In fact, fiber reinforced concrete is now a worldwide-used material characterized by an enhanced behavior at ultimate limit states as well as at serviceability limit states, thanks to its ability in providing a better crack control. This paper aims at investigating tension stiffening by discussing pure-tension tests on reinforced concrete prisms having different sizes, reinforcement ratios, amount of steel fibers and concrete strength. The latter two parameters are deeply studied in order to determine the influence of fibers on crack patterns as well as the significant effect of the concrete strength; both parameters determine narrower cracks characterized by a smaller crack width.