Abstract

INGA, Hainer  and  GUTIERREZ, Wilfredo. Implementation of the ramcodes design curves of unsaturated subgrade soils in the design of flexible pavements. Tecnia [online]. 2022, vol.32, n.2, pp.112-126.  Epub Aug 08, 2022. ISSN 0375-7765.  http://dx.doi.org/10.21754/tecnia.v32i2.1388.

The design process for a pavement structure assumes that the subgrade will saturate at some point during the service life. However, the saturation of the subgrade depends on the conditions of the region which is located. Therefore, it is necessary to study the design conditions for unsaturated subgrades. The objective of this research is to implement the spectrum of RAMCODES design curves of unsaturated subgrades for silty clayey sands, applied to the design of flexible pavements under environmental and traffic conditions associated with the Oyón-Ambo highway. To construct the RAMCODES design curves, CBR tests were performed by varying compaction energies and water contents. Likewise, using the OriginPro 2019b program, the curves were obtained, and a mathematical model was used to predict the variation of the degree of saturation in the subgrade over time. Subsequently, the seasonal CBR were obtained and correlated to obtain the resilient moduli. Finally, two flexible pavement structure designs were carried out, one of them using the traditional subgrade characterization methodology and the other according to the proposed methodology. From the results obtained, it is interpreted that the consideration of the unsaturated behavior of the subgrade optimizes the pavement design since the resilient modulus of the subgrade is increased by 28.8%, which means that the thickness of the subbase layer is reduced by 25%.

Keywords : Unsaturated soils; RAMCODES; pavement design; subgrade.

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