Controle tecnológico do concreto reforçado com fibras de PET pelo ensaio Barcelona

Abstract

Conventional concrete behaves in a fragile way, being unable to withstand any load after its rupture. This behavior changes by adding fibers to the blend, providing residual strength and toughness to the composite. These properties, as well as the change in compressive strength and tensile strength of concrete, depend directly on the fiber material used, length, section and fiber content employed. In the presented research, the influence of PET (polyethylene terephthalate) fiber on concrete is evaluated in three different concentrations (0 kg/m³, 3,5 kg/m³ and 7,0 kg/m³) with a size of 4x50mm. The incorporation of this kind of fiber into concrete aims at reducing material that would be discarted, reusing it in a new field. The following properties were evaluated: workability, axial compressive strength, diametral tensile strength, tensile strength by Barcelona test, residual strength and toughness. The Barcelona test is already a standardized method in Spain for obtaining these properties in fiber reinforced concrete (FRC), showing consistent results over JSCE-SF4. The compressive strength results obtained demonstrated that the addition of PET fibers did not change this property. However, from the Barcelona test, a reduction in the tensile strength of the composite with the addition of fibers was verified. In addition, there was an increase in residual strength and toughness with the incorporation of PET fibers, increasing about 17% of toughness in the composite with 7,0kg/m³ of fiber compared to the 3,5kg/m³ content.