01373747

Component

Pavement recycling is growing in the US. At 2.7 million miles of paved roads, the United States has the largest network of roads in the world. The mainstream approach to pavement rehabilitation has been to mill the deteriorated asphalt and replace with new asphalt mix. The hot in-place pavement recycling process has the potential of replacing the milling and resurfacing process with substantial financial and environmental savings. Those savings are in the 30%-50% range of the cost of milling and resurfacing. In addition, emission reduction of about 70%, and 100% reuse of existing material can be realized. Material obtained from a large hot in-place recycling project in Florida was used to conduct laboratory testing to evaluate the binder PG grade and the mixing effectiveness. The Superpave mix design uses performance graded (PG) grade to quantify the binder properties and select the binder that is appropriate for the local temperature The PG grade test subjects the binder to heat and pressure to simulate short and long term aging of the binder. Therefore, the PG grade should reflect the long term performance of the recycled pavement. How is the binder PG grade impacted in the recycling process? This paper addresses recycled binder properties and mixing charts. The results reported here suggest that mixing the binder with recycling agents can restore the original binder PG grade. In fact, the recycled binder PG grade can exceed the PG grade of the original binder. Another important challenge for the hot in-place pavement recycling is the mixing effectiveness. The in place milling, rejuvenating and mixing takes place in a minute or so. It is happening on the go. How effective is the mixing process and what are the best ways to measure its effectiveness. This paper proposes a methodology to measure mixing efficiency by comparing the dynamic modulus of the mix to the theoretical modulus and use the deviation as a measure of mixing effectiveness. The results reported here showed good mixing capability for the equipment used.

This paper was sponsored by TRB committee AFK20 Characteristics of Asphalt Materials

01362476

12-0768

English

14p

2012

Transportation Research Board 91st Annual Meeting

Digital/other

Figures; References; Tables

Binders; Case studies; Evaluation; Hot in-place recycling; Pavement performance; Recycled materials

Performance Graded Binder System

Florida

Highways; Maintenance and Preservation; Materials; Pavements; I31: Bituminous Binders and Materials; I52: Construction of Pavements and Surfacings; I60: Maintenance

Transportation Research Board Annual Meeting 2012 Paper #12-0768

TRIS, TRB

Feb 8 2012 4:57PM