Roads & Paving
Producing high quality asphalt mixes with RAP
By Andrew Snook
December 1, 2016 – The Ontario Hot Mix Producers Association’s (OHMPA) 25th Anniversary Fall Asphalt Seminar focusing on producing quality hot mix asphalt kicked off this morning in Vaughan with approximately 425 people in attendance.
Donn Bernal, OHMPA’s 2016 president, welcomed attendees before introducing the first speaker of the day, Jim Musselman, asphalt performance manager for Atlanta, Ga.-based Oldcastle Materials, a division of CRH.
Musselman’s presentation focused on producing high quality asphalt mixes with high RAP contents.
He told the crowd that 75.9 million tons of RAP are used in new pavements every year in the U.S. and that 99% of the materials removed from an old pavement are reused in new pavements. About $2.3 billion is saved annually in the U.S. when compared to the cost of raw materials
Musselman stressed the need to establish goals and expectations for RAP mixtures, stressing that producers need to know the intended applications and anticipated loadings. He added that it is important to care about having high quality mixed RAP and that it’s not just “the owner’s problem.”
“It will do a lot to change the mindset of people for the use of recycled materials,” Musselman told the crowd.
Speaking specifically to contractors, he told them to make sure they keep up to date on the RAP-related specifications for their projects.
“Make sure you understand what’s allowed so you can maximize the opportunities,” Musselman told the crowd. “Be very familiar with what the specifications of a project are, because they change.”
*Average RAP content used in Ontario is between 15% and 20%, which is close to the average RAP content in the U.S., which is about 21%.
Steps for high quality
Musselman offered the crowd the basic steps to produce high quality asphalt using high RAP content:
- Establish goals and expectations for the mixture.
- Understand the specifications.
- Properly evaluate the materials.
- Engage in good materials management practices.
- Develop a high quality mix design.
- Produce the mix as designed.
- Properly construct the pavement.