Case-study on lime stabilization of soils for tracks: circuito de velocidad de Los Arcos

Abstract

Soil stabilization with lime has been assumed to be a good technique for constructing transportation infrastructures. In several conditions, it has been proved that the values of the deformation modulus obtained with these mixtures have greatly exceeded the minimum values specified in design criteria, resulting in supporting layers of roads and railway tracks with characteristics well above the ones necessary for such structures. In these situations, it would be more adequate to take into account this increase in stiffness in the design of upper-level layers, or, alternatively, to consider the decrease in the percentage of lime, in order to optimize the costs of the structural system. Usually, this is not possible since common technical specifications are prepared by default, without taking into consideration an adequate quality control of constructed layers. This optimization could turn this stabilization/treatment technique much more appealing and more economically competitive. Therefore, it seems to be adequate, for quality control purposes, to rely on performance based specifications dully supported by in situ tests aimed to evaluate the mechanical properties of compacted layers, in particular of lime-treated materials, hence enabling an optimization of track design. This paper presents the studies that have been done by taking into consideration in situ tests performed on soils stabilized with lime, during the recent construction of a specific race track in Spain: Circuito de Velocidad de Los Arcos, in the Province of Navarra. The numerical analysis of the results of the tests performed by the Portable Falling Weight Deflectometer (PFWD), on compacted layers of available soils, with and without lime mixing allowed to evaluate the deformation modulus of constructed layers.