Avaliação das características mecânicas de compósitos de cimento Portland reforçados com fibras de polipropileno aditivadas com modificadores de superfície

Abstract

The application of polymeric fibers as reinforcement in cement based composites is a highly developed technology in various applications in construction. The use of polypropylene fibers have been widely used, but with some technological limitations, mainly because of them present low interaction with the cement matrix when compared with other polymeric fibers. For this work, we sought to evaluate polypropylene fibers doped with surface modifiers, with emphasis on mechanical and microstructural characteristics of composites. Different amounts of fiber with and without surface modifying additives in matrices of Portland cement mortar after 35 days of age were evaluated. The physic-chemical interactions of the fiber with the matrix were evaluated by pullout tests and through reviews of scanning electron microscopy. Some specimens were subjected to accelerated aging tests and these samples were analyzed by electron microscopy to observe the behavior of the interaction of the fiber with the additive, but also for assessing the behavior of the fiber with the matrix after exposure to aging. The results obtained by the mechanical resistance measures uniaxial compression and scanning electron microscopy showed that a mechanical reinforcement occurs independent of incorporation of additives in fiber to additions of 1.2 kg/m3. On the other hand, the surface-treated fiber exhibited higher degree of adhesion to the matrix.