01625632

Component

The objective of this study is to determine the optimum rejuvenator dosage for a High Reclaimed Asphalt Pavement (HRAP) mixture (50% RAP) based on the rheological testing of the binder, gradation and optimum binder content of a preapproved Job mix formula of Low RAP (LRAP) (15% RAP) mixture. The two mixtures were compared through both rheological and mixture performance. Paraffinic rejuvenator was added to the HRAP mixture design to compensate the effects of aging on the RAP binder. The optimum dosage of the rejuvenator was determined based on the rheological testing completed on binder blends prepared to represent the low and high RAP mixtures. Based on the results of this testing, an 8% (based on total RAP binder) dosage of the rejuvenator was chosen for the final HRAP mixture design. The rheological testing indicated that the HRAP mixtures dosed at 8% rejuvenator would behave similarly to the LRAP mixture in terms of rutting resistance and cracking susceptibility. While the HRAP mixture did perform as well as the LRAP mixture in the rut susceptibility test, it showed a lower fracture energy and secant stiffness in the semi-circular bend geometry (SCB) fracture energy test. It was found that this may have been due to the absorption of rejuvenator into the aggregates pores, leading to a lower effective rejuvenator dosage available to the RAP binder, or due to other fundamental reasons such as voids in mineral aggregate (VMA). Further investigation demonstrated that a higher oil dosage may be necessary to improve cracking resistance.

This paper was sponsored by TRB committee AFK30 Standing Committee on Non-Binder Components of Asphalt Mixtures. Alternate title: Methodology to Determine Optimum Rejuvenator Dosage for 50% High RAP Mixture.

01618707

17-04683

English

18p

2017

Transportation Research Board 96th Annual Meeting

Digital/other

Figures; References; Tables

Cracking; Mix design; Optimization; Paraffin; Reclaimed asphalt pavements; Rheological properties; Rutting

Rejuventors

Highways; Materials; Pavements

Transportation Research Board Annual Meeting 2017 Paper #17-04683

TRIS, TRB, ATRI

Dec 8 2016 11:47AM