Molecular Dynamics Simulation to Investigate the Influence of SBS on Molecular Agglomeration Behavior of Asphalt

Styrene-butadiene-styrene (SBS) modified asphalt has been used in many road projects for its good performance at high and low temperatures. However, there was no final conclusion whether SBS could change the chemical structure of asphalt binders. The objective of this study was to analyze the impact of SBS on the molecular agglomeration behavior of asphalt binders by means of molecular simulation techniques. Two types of modifiers (SBS, MAH-g-SBS) were added into two asphalt models. Results of simulation show that three types of SBS all have impact on the molecular agglomeration behavior of asphalt binders. The impact of modifiers is largely dependent on the molecular structure of asphaltenes. The molecular agglomeration of asphalt with longer asphaltene alkane side branches is more regular. The agglomeration structure of asphalt molecules is more susceptible to SBS when the asphaltene alkane side branches are longer. The difference of influence on asphalt binders among two types of SBS is small. (C) 2014 American Society of Civil Engineers.