Avaliação de desempenho de argamassas modificadas com areia de pet e fibras de polipropileno

Abstract

The use of fibers in civil construction is currently increasing, and the most used in cementitious matrices are polymeric fibers, mainly due to their mechanical, physical and chemical properties and their low cost. In recent decades, there has also been a growing concern about the scarcity of natural resources, such as sand, a material widely used in the construction industry. The validation of new materials has motivated some researchers to seek sustainable alternatives for the production of cementitious matrices. This work was developed to evaluate the technical feasibility of coating mortars produced with partial replacement in volume of natural sand (15%) by PET sand and with the incorporation of polypropylene fibers in the contents of 0.10% and 0.20% in in relation to the total volume of the mortar. In the fresh state, the properties of consistency index, mass density, incorporated air content and water retention were analyzed. In the hardened state, the mechanical properties of tensile strength in bending and resistance to axial compression, and water absorption by capillary action, which is indicative of durability, were evaluated. The results found indicate that polypropylene fibers and PET sand at the levels studied were incompatible, as they promoted an increase in the incorporated air content and void index in the mortars, decreasing the mechanical capacity of the mixtures (resistance to axial compression and resistance to flexion traction). However, a positive point observed was that the polypropylene fibers favorably influenced the rupture form of the mortars, contributing to a less fragile rupture and, in relation to absorption, the mortars with PET sand and polypropylene fibers increased the capillary coefficient and they carried a capillary absorption proportional to time.