Contribuição ao estudo da permeabilidade e das características mecânicas de um solo laterítico estabilizado com cimento.

Abstract

This dissertation investigates the evolution of the behavior of a lateritic soil, stabilized with different cement contents and submitted to water percolation. It analyzes not only the mechanical aspects, but also those related to the permeability of the system. Samples were cast at concentrations of 0, 2, 4 and 6 percent cement; and subjected to a percolation system under constant hydraulic load for periods of 0, 3, 7, 14 and 28 days, after which they underwent the triaxial test, at the confining pressures of 100, 200 and 300 KN / m2. In the analysis of the mechanical behavior of the mixture, the aspects of shear rupture, deformation modulus, brittleness, residual strength and volumetric variation were focused. The results obtained were compared with values ​​proposed and indicated by different authors or institutions. When studying the permeability, the behavior of the permeability parameters for the different concentrations as a function of time was analyzed. The results clearly show that, for the material studied, the addition of 2% of cement became practically unimpressive, as far as the modifications introduced in the system were observed from all angles analyzed. At higher concentrations, a significant strength gain, generalized increase of the deformation modulus and less plastic behavior for the material were obtained. Non-confined resistance values ​​were calculated from the results achieved during the triaxial tests. Based on these values, and at a concentration of 61, the material meets virtually all specifications which set a minimum strength limit as a criterion for material acceptability. In general, the increase in cement concentration led to an increase in the cohesion values ​​and the friction angle of the material. The increased cure time contributes to the increase of the strength characteristics of the material; however it does so less intensely than in concrete cases. At 7 days of cure, the material already showed 78 to 841 resistance at 78 days. The permeability study showed that, for contents of 2 and 4% of cement, there was an increase in the permeability coefficient values ​​in relation to the natural, unstabilized soil. At a higher concentration, ie 6%, There was a substantial reduction in permeability. This fact was attributed to a cementation process, developed in the sample voids and promoted by the larger amount of the mixture additive. A detailed interpretation of all these phenomena, is presented in the present work.