Fig. 1. CA growth of asphalt binders at four temperatures in 1 atm air pressure (data: symbols; model calculation: dash lines): (a) Sobetirome binder; (b) emulsion WMA binder; (c) zeolite WMA binder; (d) chemical WMA binder.Figure optionsDownload full-size imageDownload as PowerPoint slide
3.2. Kinetics model optimization
According to the fast-rate, constant-rate oxidation kinetics model , asphalt oxidation, represented by carbonyl area (CA) growth, can be described by the following equations reflecting the combined fast-rate, constant-rate parallel reaction processes:equation(1)CA=CAtank+M(1-e-kft)+kctCA=CAtank+M(1-e-kft)+kctequation(2)kf=Afe-EafRTequation(3)kc=Ace-EacRTwhere CA is motor (efferent) pathways the carbonyl area of asphalt sample, CAtank is the carbonyl area of unaged asphalt, M = CA0−CAtank (CA0 is the zero-time intercept of the constant rate reaction), kf is the fast-rate reaction constant, kc is the constant-rate reaction constant, Af and Ac are pre-exponential factors for kc and kf, Eaf and Eac are the apparent activation energies for kc and kf, and R is the idea gas constant (8.314 J/mol/K).