Análisis comparativo de la evaluación de esfuerzos y deformaciones en pavimento asfaltico mediante teorías lineales elásticas y viscoelásticas
Córdoba Acosta, Carolina María
Heilbron Buelvas, Julio Ignacio
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AbstractIn this research, it is intended to evaluate and compare the calculations of the stresses and deformations in asphalt pavement using linear elastic methodology and viscoelastic methodology, taking into account that currently in Colombia most pavement designs are carried out with the AASTHO 93 methodology and later A rational methodology analysis is carried out in which stresses and deformations are calculated at the bottom of the asphalt layer and above the subgrade in order to estimate the useful life of the pavement due to fatigue and rutting respectively. However, these analyzes to determine the stresses and deformations in the structures designed by AASHTO 93 are carried out with softwares and linear elastic models, which simulate the asphalt material as a material with linear elastic behavior, described with a constant modulus of elasticity. However, in real life it is known that asphalt has a viscoelastic behavior characterized by a dynamic modulus through a master curve, this behavior is different from that currently assumed under linear elastic methods. Thus, in the present investigation 3 different pavement structures based on 3 levels of traffic were analyzed; and for these structures the design was carried out using the AASHTO 93 methodology to determine the thicknesses and then proceeded to determine the deformations at the bottom of the asphalt layer (fatigue) and above the subgrade (rutting), obtaining as a result that in the In the case of fatigue, the linear elastic analysis gives similar results to the viscoelastic analysis when the latter is analyzed at speeds similar to 60 kph. However, when the viscoelastic analysis is carried out at low speeds, a greater deformation is obtained in the viscoelastic system compared to the elastic system, since, at a lower speed, the asphalt performs with a lower dynamic modulus and therefore is generally more deformations. In this case, the behavior of the pavement would be underestimated if we have low speeds and we carry out the analysis with the elastic linear model. In the case of rutting, the elastic analysis gives a lower value than any viscoelastic analysis, which means that in all cases the rutting under the elastic analysis is underestimated, since simulating the real behavior of asphalt (viscoelastic) the values still give mayor. Therefore, when it comes to designing asphalt pavements, it is important to obtain a characterization of the speed of the road and perform a viscoelastic analysis because it represents the real behavior in the field.