Estudo das propriedades e fatores que influenciam o comportamento resiliente e a deformação permanente de misturas de solo-agregado granítico

Abstract

This work aims to understand the behavior of soil-aggregate mixtures used in the southern region of Rio Grande do Sul and to evaluate the main factors that influence the mechanical and deformational properties of said mixtures. The studied soil constitutes young residual soil, little weathered, belonging to the 'C' horizon of the local geological profile, commonly called gravel. The aggregate, on the other hand, originates from a granitic acid igneous rock, belonging to the Batólito de Pelotas geological formation. The methodological procedures used in the work consist of the physical and mechanical characterization of the soil and aggregate and the proposition of three mixtures within the C range of the main standards that designate the use of soil-aggregate in the composition of base and sub-base layers pavement structures. For this purpose, ISC, MR and DP tests were carried out for the soil and mixtures. The ISC and MR tests were carried out in the optimum moisture content and in the humidity variations established in the norm, pre and post compaction, in addition to the variation in the compaction energy, in the optimum moisture content. In turn, the DP tests were performed at the optimum moisture content at a frequency of 2Hz. Finally, the degradation of the aggregate and the influence of suction on the deformational behavior were determined. Regarding the ISC, even with increased energy, the compacted specimens in the variations of the optimum content showed less carrying capacity than in the content. In the MR test, the values were higher the lower the moisture content, particularly when the compaction was performed at the optimum level and the specimens were subjected to drying. The increase in humidity in both compaction conditions promoted a simple reduction in the MR. That said, it was identified that the models that best represented the resilient behavior were the composite and universal, considering that both considered the joint action of the tensions confident and deviation. Regarding the permanent deformation, both the soil and the mixtures, presented satisfactory performance in relation to the ATR and the accommodation tendency, being classified in types A, AB and B, with no rupture of the materials. With these results, there was also a good correlation with the parameters of Guimarães (2009). The suction measures showed that the parameter has an inverse relationship to the percentage of aggregate of the mixtures, highlighting the model by Liang (2008), which showed a good correlation between the parameter and the resilient properties of the materials. Finally, when evaluating the use of mixtures in the constitution of base layers, through design carried out by the methods of DNER (1981) and by MeDiNa (2019), it was found that the structures proposed by the current method would suffer rupture due to fatigue from the end of the project period, on the other hand, the structures proposed through MeDiNa (2019) meet the criteria of fatigue and permanent deformation, demonstrating the potential use of these soil-aggregate mixtures in the composition of base layers.