Estudo do comportamento mec?nico de Comp?sitos Solo - Fibras Vegetais impermeabilizadas com Solu??o de Poliestireno Expandido (EPS) e Cimento Asf?ltico de Petr?leo (CAP).

Programa de P?s-Gradua??o em Engenharia de Materiais. Rede Tem?tica em Engenharia de Materiais, Pr?-Reitoria de Pesquisa e P?s-Gradua??o, Universidade Federal de Ouro Preto.A crescente preocupa??o com o meio ambiente e o uso de produtos naturais tem contribu?do fortemente para o uso de materiais derivados da biomassa, e em particular fibras vegetais. Algumas vantagens s?o atribu?das ao uso de fibras vegetais em muitas aplica??es industriais quando comparado a fibras sint?ticas. A fibra vegetal vem de fontes renov?veis, ? at?xica, de baixo custo e tem menor densidade. Outro aspecto importante a ser considerado no uso de fibras vegetais ? a gera??o de empregos rurais e industriais. Assim, as implica??es sociais e ambientais de seu uso tamb?m devem ser reconhecidas. No entanto, a r?pida absor??o e dessor??o de ?gua e a degrada??o de fibras vegetais podem representar caracter?sticas negativas. Assim, um estudo sobre o efeito do tratamento superficial das fibras vegetais, visando diminuir sua higroscopicidade e aumentar sua durabilidade ? necess?rio para a que estas possam substituir com sucesso as fibras sint?ticas. Neste contexto, o objetivo desta pesquisa foi analisar o comportamento mec?nico de um solo granular refor?ado com a inclus?o aleat?ria de fibras de curau? e sisal, naturais e superficialmente tratadas com solu??es de EPS (poliestireno expandido) e CAP (cimento asf?ltico de petr?leo). Estas fibras foram misturadas ao solo granular para a avalia??o da influ?ncia de tais materiais na melhoria das propriedades mec?nicas da mistura. A fim de caracterizar o desempenho destas fibras foram realizadas caracteriza??o qu?mica, microscopia eletr?nica de varredura (SEM), an?lise din?mico mec?nica (DMA) e an?lises microbiol?gicas. Tamb?m uma s?rie de ensaios geot?cnicos foram realizados sobre as amostras com 0% e 0,50% de teor de fibra e 24, 36 e 50 mm de comprimento. A influ?ncia do teor e comprimento de fibras sobre as propriedades do solo arenoso refor?ado foram estudadas atrav?s de ensaios triaxiais drenados. Os resultados indicaram que a inclus?o de fibras vegetais melhora as propriedades geot?cnicas das amostras. Observou-se que o refor?o fibroso aumenta a resist?ncia ao cisalhamento de pico e os par?metros de resist?ncia ao cisalhamento das amostras de solo em ensaios de compress?o triaxial. Constatou-se que a adi??o de fibras vegetais naturais e tratadas confere melhoria significativa no comportamento mec?nico deste solo, e o potencial das fibras de curau? e sisal como elemento de refor?o. Os pol?meros utilizados foram adequados ? an?lise proposta, cobrindo a superf?cie das fibras vegetais e aumentando sua durabilidade.The increasing concern about the environment and the use of natural products has strongly contributed to the use of materials derived from biomass, and in particular vegetal fibers. Some advantages are attributed to the use of vegetal fibers in many industrial applications when compared to synthetic fibers. The vegetal fiber comes from renewable sources; it is nontoxic, shows low cost and have lower density. Another important aspect to be considered in the use of vegetal fibers is the generation of rural and industrial jobs. Thus, social and environmental implications of their use should also be recognized. However, the rapid absorption and desorption of water and degradation of vegetal fibers can represent negative characteristics. Thus, a study of the effect of vegetal fibers surface treatment in order to decrease its hygroscopicity and increase its durability is necessary for the successful replacement of synthetic fibers by these fibers. In this context, the aim of this research was to analyze the mechanical behavior of a granular soil reinforced with random inclusion of curau? and sisal fibers, natural and superficially treated with solutions of EPS (expanded polystyrene) and CAP (asphalt). These fibers were mixed to the granular soil to evaluation the influence of such materials on the mechanical properties improvement of the mixture. In order to characterize the performance of these fibers, chemical characterization, scanning electron microscopy (SEM), dynamic mechanical analysis (DMA) and microbiological analysis were employed. Also a series of geotechnical laboratory tests were performed on the specimens with 0% and 0.50% fiber content and 24, 36 and 50 mm in length. The influence of fiber content and length of fiber on the reinforced sandy soil properties were studied by drained triaxial tests. The test results indicated that the inclusion of vegetal fibers increases the geotechnical properties of the specimens. It was observed that fiber reinforcement increases the peak shear strength and shear parameters of the soil samples in compression triaxial tests. Through the obtained results, it was observed that the addition of natural and treated vegetal fibers conferred significant improvement to the mechanical behavior of this soil, and it was shown the curau? and sisal fibers potential as soil reinforcement. The polymers used were suitable to the proposed analysis, covering the vegetal fibers surface and increasing their durability