CEN Master's Thesis Presentation Natalie Youstos
CIE Conference room
: Virtual using teams
Walaa Mogawer
508-910-9824
wmogawer@umassd.edu
Abstract
Development of a Balanced 100 Percent Reclaimed Asphalt Pavement Mixture Using Cracking and Rutting Performance Tests by Natalie Youstos
The use of reclaimed asphalt pavement (RAP) at high contents can reduce the demand for virgin aggregate and binder, lower construction waste, and support more sustainable asphalt pavement production. However, 100% RAP mixtures are challenging because the aged RAP binder can improve stiffness and rutting resistance while reducing workability, compactability, and cracking resistance. Therefore, 100% RAP mixture design requires a balanced performance approach that evaluates both cracking and rutting resistance. This study evaluated 100% RAP asphalt mixtures produced with fractionated RAP materials from a RAP source in New York. The main objective was to identify an additive system capable of meeting the New York State Department of Transportation (NYSDOT) balanced
mix design criteria. In this thesis, an additive system refers to a combined modification approach that may include added binder, polymer-modified binder, crumb rubber, asphalt-rubber binder, recycled asphalt shingles (RAS) pellets, and/or recycling agents. The evaluated recycling agents were coded as R1 and R2. R1 represents a petroleum-based rejuvenator, while R2 represents a bio-based oil rejuvenator. Cracking resistance was evaluated using the Indirect Tensile Asphalt Cracking Test (IDEAL-CT), with the Cracking Tolerance Index (CTIndex) used as the cracking performance parameter. High-temperature rutting resistance was evaluated using the High-Temperature Indirect Tensile Strength test (HT-IDT). The selected NYSDOT-based performance criteria were CTIndex ≥ 135 and HT-IDT ≥ 30 psi. The results showed a clear cracking–rutting tradeoff among the evaluated mixtures. Several mixtures satisfied either the cracking criterion or the rutting criterion, but only one mixture satisfied both requirements. The most promising mixture contained 1% polymer-iii modified binder (B3), 0.85% R1, 65% RAP sand, and 35% 9/16 in. RAP stone. This mixture achieved an average CTIndex of 189.14 and an average HT-IDT strength of 31.07 psi. The B3 mixtures showed that increasing R1 dosage improved cracking resistance but reduced high-temperature strength, indicating the need for careful dosage control. Overall, the balanced mix design framework was effective in identifying a candidate 100% RAP mixture that satisfied the NYSDOT cracking and rutting criteria. Additional validation through aging, moisture susceptibility testing, plant production, and field monitoring is recommended before implementation.
Keywords: 100% RAP, reclaimed asphalt pavement, balanced mix design, IDEAL-CT, Cracking Tolerance Index, HT-IDT, NYSDOT, recycling agent, polymer-modified binder,cracking-rutting balance.