Date of Award

12-2011

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Civil Engineering

Advisor

Putman, Bradley

Committee Member

Bridges , William

Committee Member

Poursaee , Amir

Committee Member

Rangaraju , Prasad

Abstract

This study was conducted to determine the effect of warm mix (WMA) modifiers on asphalt mixes containing high percentages of reclaimed asphalt pavement (RAP). Mixes were created using three aggregate sources, four RAP percentages (0%, 20%, 35%, and 50%), and three warm mix modifiers (HMA, zeolite, and Sasobit®). Base binders from the same source (PG 64 -22, 58 -28, 52 -28) and one rejuvenator were used for each mix to ensure the final blended binder grade was at least PG 64 -10.
Specimens were created at HMA or suggested WMA temperatures and tested for rut depth, indirect tensile strength (ITS), tensile strength ratio (TSR), and fatigue life. Additionally, mixtures from one aggregate source were tested for resilient modulus. Selected binders were then examined using Fourier transform infrared spectrometry (FTIR-ATR) to examine the IR absorbance at wave numbers 1700 cm-1 and 1030 cm-1 to quantify binder aging to determine if exhibited properties, namely fatigue life, were an effect of oxidative aging.
The study found that, for a given RAP percentage zeolite often produced mixes with less favorable properties than HMA and Sasobit® often produced mixes with nearly equivalent or better properties than HMA. FTIR analysis showed RAP mixes to increase in oxidation as RAP percentage increased, and Sasobit®-modified base binders did not show increased aging over HMA base binders. Fatigue life was found to be more strongly correlated to oxidation of the binder's sulfoxide group, while resilient modulus at 5°C was found to correlate to oxidation of the binder's carbonyl group.

Share

COinS