Effect of lime stabilization on the mechanical and micro-scale properties of recycled demolition materials

Abstract

Sustainable reuse options for Construction and Demolition (C&D) materials in civil engineering applications have been an emerging topic in recent years. Crushed Brick (CB), Recycled Crushed Concrete (RCA) and Reclaimed Asphalt Pavement (RAP) comprise a major fraction of the wastes going to landfills. This research investigates the performance of lime stabilized C&D materials as road materials. Tests were undertaken on unbound and lime stabilized C&D materials with 1% to 5% hydrated lime. The laboratory investigation included particle size distribution, California Bearing Ratio, modified Proctor compaction, Repeated Load Triaxial (RLT) test and Unconfined Compressive Strength (UCS) tests. The effect of temperature curing, up to 40°C was investigated and compared to ambient temperature. The resilient modulus results indicated that the lime stabilized RCA and CB were viable options for construction of subbase layers of pavement while RAP did not meet the requirements of a road construction material. UCS values of RCA and CB met the minimum requirement for cementitious materials after 7days of curing. In addition to evaluating the mechanical properties, micro-scale analyses were also conducted using Scanning Electron Microscope (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) to understand the behavior of the lime stabilization of C&D materials.