Francis C. Turner Lecture - Quarry By-Products and Their Sustainable Pavement Applications

Aggregates are ubiquitous in every American’s life, whether they are aware. According to the U.S. Geological Survey, the U.S. produces around 1.5 billion tons of crushed stone and 1.0 billion tons of sand and gravel each year. In transportation, considering the interstate highway system alone, aggregates comprise 94 % of materials used during construction.  Aggregate production in quarries are faced with challenges of utilizing 100% of their product, as inevitably material by-products are generated as screenings, pond fines, and/or baghouse dusts, and the amount of unused by-product may increase as gradation requirements become stricter, especially when cleaner products are blended with recycled aggregates. In fact, depending on the rock and crusher types, upwards of 20 % to 25 % of the final aggregate product may end up as quarry by-product with an estimated national production 175 million tons per year. The talk will cover research efforts undertaken at the Illinois Center for Transportation (ICT) in the last two decades focusing on how to build sustainable pavements with quarry by-products/fines, which are generated in excessive amounts from stone quarries.