Bearing capacity of steel fiber reinforced concrete with different fiber types

Abstract

The paper presents study results of the load-bearing capacity of fibroconcrete during dispersed reinforce-ment with steel fiber of three different types - anchor, flattened and corrugated. In all experiments, fiber was added in an amount of 1% by volume, which, as established in the preliminary tests conducted by the authors, is the op-timal percentage of reinforcement. The tests were performed on prisms and cubes measuring 100x100x400 mm and 100x100x100 mm, respectively, aged for 28 days.Four groups of prisms and cubes were manufactured. One - from usual concrete (with the sizes of large aggregate to 10 mm) of the C20/25 class, and three more - with different types of fibers. Each group consisted of six samples. All tests were performed on a press specially prepared for this purpose. Clock-type indicators, one for each, were attached to the side surfaces of the prisms to measure longitu-dinal deformations during loading. The load was applied in equal steps with a holding time of 10 minutes. The test results are presented in the form of graphs of the dependences of the relative deformation on the stress and in tab-ular form. When testing the cubes, only the maximum loads were recorded, due to the impossibility of stable fixing of sensors. It was found that the load-bearing capacity of steel fiber does not depend on the fiber type, but its pres-ence in the concrete changes the nature of the destruction of the sample. Instead of instantaneous brittle destruc-tion, a slow current process is observed, and the prism does not disintegrate into separate parts, but remains a single array with through cracks; fiber fibers keep it from final destruction. Prisms with steel fiber content with-stood loads 11% higher than concrete samples. The use of steel fiber improves not only the load-bearing capacity, but also the deformability. The relative longitudinal deformation of reinforced concrete was on average 36% higher than that of concrete due to the presence of pseudoplastic deformation phase in fibroconcrete.