Efeito da adição de fibras sintéticas e naturais nas propriedades físicas e mecânicas de argamassas autonivelantes com metacaulinita

Abstract

This research presents the development and physical-mechanical characterization of cement-based composites reinforced with polypropylene, jute and mallow fibers. In order to increase the durability of plant fibers in composites, a matrix was developed with partial replacement of Portland cement by 50% of metakaolin to decrease calcium hydroxide levels, which degrade these fibers. The fibers were characterized in terms of their mineralogical composition and morphology by X-ray diffraction (XRD), thermogravimetry (TG / DTG), scanning electron microscopy (SEM), water absorption test. The matrix was characterized by physical tests (TG / DTG and rheology) and the characterized composites passed mechanical (compression and flexural tensile) and physical (dimensional variation and water absorption) tests. It was verified from the SEM tests that the polypropylene fiber has a standard morphology, while the natural fibers presented a structure of fibrocells, lumens and medium lamella. TG / DTG results showed that partial cement replacement decreased calcium hydroxide content by 100%. Metakaolin matrices had gains of up to 47,61% in flexural tensile strength in relation to the reference matrix (R). As for the flexural tensile behavior, the fiber matrices had an increase of up to 22.03%, compared to R. The dimensional variation tests confirmed the viability of the use of plant fibers and metakaolin as a solution to combat the problems of shrinkage in self-leveling floor mortars.