Abstract
This study evaluated the viscoelastic properties of a performance grade (PG) binder blended with different percentages of binders recovered from reclaimed asphalt pavement (RAP) for conditions (materials, climate, and specifications) prevailing in Oklahoma. The viscoelastic properties of the blended binders were then used to estimate dynamic modulus ( E ∗ ) values of the new mixes with RAP by using the Witczak model through time-temperature superposition (TTS) principles. The recovered binder from RAP was found to be significantly stiffer than the virgin binder (PG 64-22). The addition of RAP increased the complex modulus ( G ∗ ) of the base binder, so did the E ∗ of the corresponding mix. The creep stiffness resistance of the asphalt binder at low service temperatures decreased with the addition of RAP. With up to 10% RAP binder, no notable changes were observed in the viscosity and PG grade of the virgin binder. With 25% and 40% RAP binder, the PGs of the blended binders were found to be PG 70-16 and PG 76-16, respectively. It was observed that the E ∗ master curves predicted from PGs of the blended binders were in close agreement with those estimated from the laboratory-measured E ∗ data. The dynamic shear rheometer (DSR) data of rotational thin film oven (RTFO)-aged blended binders predicted significantly lower E ∗ values compared to the measured ones. The E ∗ values predicted from rotational viscosity (RV) test data were found to be higher than the measured E ∗ values. The findings of this study are expected to provide transportation professionals with a better understanding of new mixes with high RAPs.
Highlights
Introduction and BackgroundAsphalt concrete (AC) is the most recycled product in the US due to its beneficial effects on reducing the consumption of virgin materials and providing increased environmental stewardship
It was observed that the E∗ master curves predicted from performance grade (PG) of the blended binders were in close agreement with those estimated from the laboratory-measured E∗ data. e dynamic shear rheometer (DSR) data of rotational thin film oven (RTFO)-aged blended binders predicted significantly lower E∗ values compared to the measured ones. e E∗ values predicted from rotational viscosity (RV) test data were found to be higher than the measured E∗ values. e findings of this study are expected to provide transportation professionals with a better understanding of new mixes with high reclaimed asphalt pavement (RAP)
The major objectives of this study are as follows: (a) evaluating the effects of high RAP on rheological and mechanistic properties of different RAP-blended binders and mixes and determining their corresponding Mechanistic-Empirical Pavement Design Guide (MEPDG) input parameters for conditions prevailing in Oklahoma; (b) estimating the E∗ master curves of RAP mixes from viscoelastic properties of blended asphalt binders
Summary
Introduction and BackgroundAsphalt concrete (AC) is the most recycled product in the US due to its beneficial effects on reducing the consumption of virgin materials and providing increased environmental stewardship. Significant efforts have been made by federal and state agencies as well as various focus groups to promote the use of high reclaimed asphalt pavement (RAP) content by working with state Departments of Transportation (DOTs) on field projects, which demonstrate the performance of high RAP mixes [1]. Even though the beneficial effects are high, several state agencies including the Oklahoma Department of Transportation (ODOT) do not allow the use of “high RAP” in mixes for their roadways. In the hierarchical approach of the MEPDG, laboratory test data of asphalt binders and asphalt mixes are required to obtain the highest reliability (Level 1).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
