Estudo de dosagens de concreto para aumento da resistência à tração na flexão

Abstract

Brazil has in recent years a big jump in civil construction, where it was possible to observe works of small, medium and large sizes. This fact coupled to the fact that concrete is the main product of construction, increased the intake to levels never seen before. Concrete has different characteristics due to different types of cement, aggregates and additives used; However the main characteristic remains the compressive strength. With increasing demand, also increased rigor to properties of concrete, and one of these properties is tensile strength, which if less than the amounts stipulated in the project, can compromise the structural integrity of the piece and even generate pathological manifestations. Given the above, this paper presents a comparative of concrete dosages to obtain a higher tensile strength and a greater relationship between compressive strength and traction. The dosages were made varying the levels of cement content and mortar content in compositions with crushed gravels 0 and 1, plus the addition of steel and polypropylene fibers in order to evaluate its behavior. Prismatic samples of 500x150x150mm were molded for disruptions in traction in flexion according to NBR 12142:2010, and cylindrical samples to disruptions in compression according to NBR 5739:2007. Was also made a comparative of disruptions of dry and saturated prims. The results showed that the addition of fibers alters the resistance to traction and also that concrete compositions only with gravel 1 and gravels 0-1, have different behaviors. In line, the dry and saturated disruptions showed distinct behaviors.