Particle Size Characteristics of Unconventionally Large Aggregate Particles by Stereophotography

In recent years, the use of unconventionally large aggregates for subbase layer construction has become popular. Such aggregates generally require less crushing than conventional size aggregates; therefore, the use of such aggregates can help to achieve energy savings and improved pavement sustainability. The engineering properties of aggregates greatly depend on the particle size distribution; therefore, size characteristics of aggregate particles must be well known. Sieve analysis may not be practical for unconventionally large aggregates due to the limitations of the existing test apparatus. In this study, stereophotography, a digital imaging technique, was evaluated as an alternative to sieve analysis to determine the size characteristics of aggregate particles. Sieve analysis and stereophotography were performed on an unconventionally large aggregate material. Their results were compared and it was concluded that the digital imaging technique was a very useful approach for size characterization of aggregate particles.