The next great thing in the Asphalt World is Balanced Mix Design (BMD).  New York has a version of that called Performance Engineered Mixtures (PEM). Currently it isn’t doing a true balanced design, but more utilizing test thresholds to qualify mixes for rutting and cracking.  The ultimate goal of PEM mixes is to give industry an opportunity to innovate.  This could mean increasing reclaimed asphalt pavement (RAP) percentages, or introducing other additives (rejuvenators, plastics, warm mix additives, etc.)  Rubber could potentially be on that list too as rubber is already allowed by spec as a liquid binder modifier to replace SBS/SB polymers.  When polymer pricing was volatile, liquid suppliers may look at rubber as an option.  But there has been little movement in that direction. In the 90’s and during the rubber mandates, rubber has been used as an aggregate replacement (crumb rubber) in several states (e.g., New York and Massachusetts) with limited success. This project aims to develop BMD using innovative additives to asphalt and solid waste (e.g., RAP, slug, fly ash) to substitute aggregates for sustainable and low carbon highway and airport pavement.