Utilization of recycled concrete aggregates for light-stabilization of clay soils

•Recycled concrete aggregates are a sustainable replacement for cement in stabilization of clay soils.•Recycled concrete aggregate inclusion in clay soil leads to higher compressive and shear strength.•Recycled concrete aggregate addition to clay soil reduces deformability and settlements.•Clay soil modified with 15% recycled concrete aggregate is strong enough to be used as subbase of rigid pavements. Due to the abundance of urban building constructions and renewals in developing and developed countries, there is a continuous increase in the amount of construction and demolition (C&D) wastes that is landfilled. Recycling and reuse of construction and demolition materials, in applications such as in pavement constructions and non-structural building elements, results in preserving natural resources and reducing environmental pollution. This experimental study evaluates the viability of using recycled concrete aggregates (RCA) for improving the shear/compressive strengths and deformation properties of clay soils. A comprehensive series of compaction, uniaxial compression and direct shear tests were performed on carefully proportioned mixtures of RCA and a clay soil. Test results and observations indicate that the introduction of RCA to clay soils results in lower dry density and higher unconfined compressive strength (UCS) which increases with moist curing. Clay soils mixed with RCA have higher tendencies for dilative behavior (during shear) and enhanced shear strengths compared to the parent clay soil. Mixing RCA with clay soils results in stronger, stiffer and less compressible blends that are particularly suitable for construction purposes such as sub-base/subgrade of road pavements.