Tension stiffening behavior of self compacting high strength fiber reinforced concrete incorporating river gravels

This study proposes a comprehensive analysis on the structural performance of reinforced Self Compacting High Strength Fiber Reinforced Concrete members. Particularly, it summarizes the results of an experimental investigation aimed at analyzing the tension stiffening behavior of concrete mixtures produced with different kinds of natural aggregates: crushed granite and two types of amazon river gravels (derived from two different Brazilian regions). The mixtures were proportioned in order to achieve 60 MPa of compressive strength and, moreover, beyond three plain concrete mixtures, 35 mm length steel fibers were added to these mixtures, as spread reinforcing element, in volumetric fractions equal to 0.5% and 1.0%. The results derived from this type of test furnish a comprehensive analysis on the crack formation and propagation on concrete elements as well as distributed cracking mechanisms. The results indicate that the adherence between the steel bar and the concrete is not affected by the presence of the river gravels and that the fiber reinforcement controls crack width leading to a great number of cracks and, this effect is more pronounced for higher volume fractions.