Recycled concrete aggregate as alternative pavement materials: experimental and parametric study

Recycled concrete aggregate (RCA) is one of the alternatives to virgin material that has engendered interest in recent years, especially as an alternative aggregate. There are limited available studies assessing the suitability of RCA as a base or subbase material in pavements. Therefore, the present research describes different laboratory experiments to determine the possibility of using RCA as alternative subbase material for road pavement in order to conserve natural resources and reduce geoenvironmental effects. Modified compaction tests, particle-size distribution, Los Angeles abrasion, Atterberg limits, specific gravity, California bearing ratio, and repeated load triaxial tests were carried out for that purpose. RCA was also reinforced with both biaxial and triaxial geogrids for material optimization. Shakedown analysis and parametric investigation using some constitutive models were conducted for further assessment. The physical and geotechnical properties showed that RCA is strong enough and fulfills the local road authority requirements to be used as a subbase material. The resilient modulus values of the reinforced RCA with geogrid was higher than the unreinforced RCA; in addition, the permanent deformation properties of reinforced RCA with geogrid was found to be smaller than that of the unreinforced RCA. The shakedown ranges varied from A to B, which indicates that RCA can be used as pavement subbase material when it is compacted with moisture content less than the optimum. The parametric investigation showed that some constitutive models are capable for assessing the behavior of both reinforced and unreinforced materials.