Study of the influence of the instability of toughness tests on the post-cracking response of high-strength concrete made with micro-silica and fibers

High-strength concrete is one that is used in large structures such as dams, bridges, and skyscrapers. This type of concrete, the higher the resistance, tends to be more brittle. Therefore, fibers are added to improve their post-cracking behavior. Recent studies found that concretes with resistant matrices and low fiber dosages tend to present instabilities during the execution of toughness tests. However, these studies did not investigate the occurrence of these instabilities in high-strength concrete and the effects of these instabilities on post-cracking response. For this reason, it is proposed to investigate, first, the influence of several parameters such as the stiffness of the frame, the data processing system, the fiber dosage and the test method in the appearance of these instabilities. Second, the influence of these instabilities on the post-cracking response of fiber-reinforced high-strength concrete will be investigated.

There is research on the influence of instabilities on the post-cracking behavior of normal concrete. However, there is still a lack of research on the appearance of these instabilities during the execution of toughness tests on high-strength concrete made with microsilica and fibers. Do the instabilities produced in the execution of the tests influence the post-cracking behavior of high-strength fiber-reinforced concrete?