Trr No. 1323 Materials And Construction, pp. 10-21
The adsorption and desorption behavior of asphalts varied according to their chemical compositions as evidenced by their different isotherm dhapes and adsorption amounts on RH-greywacke. Different chemical functional groups representative of heteroatomic-containing groups in asphalt showed different affinites and adsorption amounts.Benzoic acid and phenylsulfoxide had the highest adsorption affinity, followed by such species as phenanthridine, fluorenone, and napththol. Lowaffinity was shown by the least polar species, indole and napththalene. Different aggregates showed varied adsorption amounts for the same asphalt, indicating that aggregate-asphalt pairs have unique interactions betwen the active sites on the surface of the aggregate and the composition of the asphalt. A similar behavior was observed between the asphaltic models and five aggregates. Some aggregates adsorbed considerably more material that others, whereas some aggregates had more affinity for particular polar functional groups than others. Introduction of AS agent into the system reduced the amount of asphalt adsorbed. Precoating of the aggregate surface by AS agent decrease both the adsorption and desorption of asphalt.