Compaction-Induced Particle Breakage of Recycled Concrete Aggregate

ABSTRACT Recycled concrete aggregate (RCA) is a sustainable alternative that can replace or be mixed with natural aggregate used in railway applications. This requires a comprehensive understanding of the geotechnical properties, such as density, particle breakage, specific gravity, and water absorption, which are critical for assessing RCA’s durability of railway infrastructure. To date, there is a lack of research investigating RCA properties and behavior in conditions such as railway environments. To bridge this gap, this article examines RCA under such conditions. Furthermore, it proposes a novel vibratory compaction method that can be easily implemented using a sieve shaker apparatus. Testing was undertaken on a granitic natural aggregate and two different RCA mixes, and the analyses were carried out to assess (i) the density and particle breakage of aggregates with controlled particle size distribution and (ii) the specific gravity and density of RCA based on railway acceptance criteria established for natural aggregates. Results show that vibratory compaction with a 1.2-kPa vertical stress surcharge produced RCA densities that meet railway ballast requirements. The particle breakage induced by vibratory compaction of RCA was 14 % to 38 % of the particle breakage imparted by modified Proctor compaction. These results substantiate the potential of RCAs as a viable, sustainable alternative for use in railway infrastructure, offering comparable results to conventional natural aggregates.