Estudo da aplicação de argamassa de alta resistência como reforço estrutural de vigas em concreto armado

Abstract

Reactive Powder Concrete (CPR), classified as an UHPC (Ultra High Performance Concrete), has high visibility and attention in the area of concrete technology, due to its promising properties and performance such as high strength and durability. However, despite its great scientific prominence, it is still not common to see its use in real civil construction applications. Initially, the work was intended to analyze the performance of CPR in structural reinforcement applications in concrete beams. However, in the production stage of the specimens, more water was added than the expected mix and the wet curing stage was not performed, causing the material produced not to reach the desired characteristics, especially of high resistance. Then, the reinforcement used was disqualified as reactive powder concrete and classified as a high-resistance mortar. With this new definition, the objective of the study was to evaluate the behavior of the material regarding its mechanical strength, deformability and adhesion to the structure to be reinforced, to study the feasibility of this application in a real scenario. The methodology used was experimental research. As a study model, beams were made in conventional reinforced concrete, which after adequate curing time received a reinforcement composed of high-strength mortar. For comparison purposes, a proportion of the samples were not reinforced. From the specimens, three-point bending and axial compression tests were performed on samples of the produced mortar. The mortar compressive strength results had an average of 25 MPa, compared to the fck of 20 MPa of the conventional concrete produced. In the bending tests, the material presented a positive performance in the structural reinforcement of the concrete beams when positioned in the element’s compression region, increasing the bending strength by 40.38% when compared to the reference samples. Tests were also carried out with the reinforcement positioned on the underside of the beam, to analyze its behavior in the structure’s tensile region. In this case, the strength values were lower than the reference samples, indicating that the mortar layer ruptured by traction tension.