Influence of fine content and water content on the resilient behaviour of a natural compacted sand: Fid-Bau Portal

Influence of fine content and water content on the resilient behaviour of a natural compacted sand

Ho, Xuan Nam / Nowamooz, Hossein / Chazallon, Cyrille / Migault, Bernard

Granular materials are often used in pavement structures. The influence of fine content and water content on the mechanical behaviour is very important. In this work, first, we present the resilient behaviour of compacted clayey natural sands with two different fine contents using the repeated load triaxial tests. The samples were compacted at different water contents with the same dry density. It can be stated that an increase in the fine content (from 4% to 7.5%) causes an increase in the volumetric strains and shear strains for all the water contents. The influence of water content can be considered negligible comparing to the influence of fine content. Then, the experimental results were simulated using the nonlinear elastic model (modified Boyce model) generally used for the resilient behaviour of the unsaturated granular soils. The results show that the model can correctly predict the variation of the volumetric strains and the shear strains with the mean stress for all the stress paths. Finally, finite element calculations carried out with CAST3M were performed to compare the deflection of a low traffic pavement with sub-base layers containing two different fine contents. The surface asphalt concrete layer and the base layer were taken the same for both structures. The modelling results show that the sub-base soil with higher fine content produces 37% higher deflection in the whole structure and that the effect of the water content is lower than that of the fine content.