Análise da influência das microfibras de polipropileno no controle da retração hidráulica no concreto autoadensável

Abstract

Within the area of materials and structures, self-compacting concrete emerged as a material that combines mechanical properties already presented by conventional concrete to the rheological characteristics of fluidity and homogeneity, properties required during the execution of concrete structures. Despite many advantages of using this material, there are still some manifestations caused by shrinkage. This is the case of cracking resulting from the hydraulic shrinkage process. The objective of this research is to evaluate the influence and consequences of the retraction mechanism in the early ages of self-compacting concrete, proposing the addition of polypropylene microfibers to combat the effects of retraction. Proportions of 0.05%, 0.10%, 0.15% and 0.20% and polypropylene microfibers of different relation aspect. In order to evaluate the characteristics resulting from this addition, the test method of ASTM (2013) C1579 was chosen. After the tests and analysis, the results showed that the longer fibers, with a volume of 0.20%, obtained higher efficiency, reaching at a rate of reduction of the cracking area of about 99%. It has also been shown that an increase in the relation aspect reflects an increase in fiber efficiency.