Influência da adição de fibras de polipropileno na resistência e na retração de um concreto compactado a rolo

Abstract

This work aims at evaluating the influence of two different lengths of polypropylene fibers which were added to the Roller-Compacted Concrete (RCC) on its resistance to axial compression, diametric compression, and retraction suffered by the material during its curing and useful life, so as to be used in the basis of paving. To attain the objectives of this study, there was a characterization of aggregates which were extracted from the cities of Passo Fundo and Osório in the state of Rio Grande do Sul, Brazil. The characterization evaluated the granulometry of the individual materials, and the ideal mix for such a composite, besides the checking of physical properties, such as Los Angeles Abrasion Test, absorption, and specific mass. To find moisture content, the method was the same one used in soils: Proctor Compaction Test, with different compaction energies. After the characterization, test specimens were molded to verify the resistances and the retraction. The moldings were made randomly so as to obtain higher reliability in the results, thus decreasing the influence of external factors. For axial compression tests, sixteen concrete mixes with repetition were molded, totalizing thirty two thoroughly randomized concrete mixes. For each concrete mix, eight test specimens were molded so there were four test specimens for axial compression and four test specimens for diametric compression. Retraction tests were performed with the best results of previous tests, considering the most significant factors of compression. For this analysis, three test specimens were molded for each mixture, totalizing three different mixtures and nine retraction tests. There is a greater influence of the cement proportion and of the compaction energy, thus the test specimens which were molded with a higher proportion had better results