100% Hot Mix Asphalt Recycling: Challenges and Benefits

TLDR: In this article, the authors investigate the concept of 100% recycling, determine whether such mixtures can perform as well as conventional asphalt mixes and if yes, develop a mixture design method for 100% recycled asphalt.

Abstract: Dramatically rising asphalt binder cost, dwindling budgets, growing traffic loads, and the desire to find more sustainable paving practices are forcing agencies to seek ways for maximizing the re-use of Reclaimed Asphalt Pavement (RAP). While most of the academic and industrial institutions have been focused on the development of procedures to recycle hot asphalt mixes with up to 40% RAP content, a few industry innovators have refined 100% recycling technologies over the past four decades to a level where routine production of 100% recycled mixes is in clear sight. The main hindrance in the widespread use of 100% recycling is the unproven performance of 100% RAP pavements and lack of a unified and rational system for selection of materials and mix design. The objective of this research was, therefore, to critically investigate the concept of 100% recycling, determine whether such mixtures can perform as well as conventional asphalt mixes and if yes, develop a mixture design method for 100% recycled asphalt. This article presents a summary of the research, demonstrating that with adequate mixture design 100% recycled asphalt mixtures can perform equally to conventional asphalt. The available production technologies are also shortly summarized. Finally an environmental effect and cost calculation is performed demonstrating reduction of emission by 35% while reducing the costs of materials by half.