Behavior of flexible pavement structures with cement-treated bases

Abstract

In pavement engineering, treating base layers with cement improves aggregate cohesion and strength, generating semi-rigid pavements. To evaluate the impact of the elastic modulus of the treated base, sections with varying cement contents and base thicknesses of 15 and 20 cm were designed. Using an empirical mechanistic approach, using ALIZE LCPC under the AASHTO axis, stresses and strains in the asphalt layer, base, and subgrade were simulated. For each configuration, tensile stresses and tangential strains were calculated using ICAFIR models adapted to the Manabí climate and available materials. The results showed that tensile stresses in the base are almost independent of its strength and thickness. However, as the elastic modulus of the base increased, it was necessary to thicken the asphalt layer to maintain allowable stresses. With a 15 cm base, increasing the modulus involved increasing the asphalt layer from 13 to 20 cm, slightly reducing tangential deformation and increasing tensile and compressive stiffness. In contrast, with a 20 cm base, the increased stiffness allowed the layer thickness to be reduced from 14 to 7 cm without exceeding the allowable stress, in addition to reducing surface deformations. These findings suggest that, on thin bases, reinforcing the asphalt layer is advantageous by improving the stiffness of the treated base. On thicker bases, surface thickness can be optimized, achieving material savings without compromising structural performance.