The Use of Automated Flocculation Titrimetry and SARA Analysis to Predict the Performance of Bituminous Binders in Asphaltic Hot Mix and Bitumen Emulsions

Bitumen is complex chemically, but its composition determines rheology. The Strategic Highway Research Program 1 (SHRP) developed a bitumen microstructural model that relies on the thermodynamic compatibility of the fractions (based on polarity) to create a thermodynamically stable continuum. This stability determines the performance of any bitumen in hot-mix and emulsion applications. Automated Flocculation Titrimetry (AFT) developed by the Western Research Institute (WRI) USA measures Heithaus parameters that define this stability. Chromatographic analysis, known as SARA (saturates, aromatics, resins and asphaltenes) provides a broad compositional analysis that may be used with hiethaus parameters to predict the performance of bitumen in mixes and emulsions. The methodology is based on work from the Western Research Institute at the University of Wyoming Laramie (USA) to measure the known Heithaus (stability) parameters accurately and reproducibly and is detailed in ASTM 6703. In this work, Reclaimed Asphalt Pavement (RAP) binders and virgin binders were examined by SARA analysis and AFT. The properties of the mixes made with these binders are determined and compared to the predictions. A set of emulsion binders with different SARA analysis were also examined for emulsability and the results compared to the AFT results.