Characterization of Granular Materials Treated with Fly Ash for Road Infrastructure Applications

This paper presents the results of an experimental investigation carried out to evaluate the effects of fly ash (FA) on the coarse-grained soils compaction response and shear characteristics for the purpose to valorize their utilization as local materials in road infrastructure applications. A series of compaction and direct shear tests was performed on three different classes derived from natural Chlef sand having different maximum grain sizes mixed with fly ash according to percentages ranging from 0% to 15%. The sand-fly ash mixture samples were reconstituted with water content varying between 4% and 14% for the whole experimental compaction testing program. The obtained data confirmed that the particle size and fly ash content have a significant influence on the mechanical performance (in terms of compaction response and shear strength characteristics) of sand-fly ash mixtures. Indeed, the increase of the maximum particle size and fly ash fraction induced a noticeable increase of the maximum dry density and decrease of the optimum water content for the tested sand-fly ash mixture samples. On the other hand, the obtained test results indicated clearly the impact of D-max and FA on the shear strength response of the sand-fly ash mixtures for the fly ash content range (0%-15%) under study. The newly introduced particle size characteristics appeared as pertinent parameters to predict the compaction response and shear strength characteristics of the tested materials.