The adsorption behavior of asphalt and functionalities representative of those present in asphalt on aggregates precoated with antistripping agents was investigated. The amount of adsorption obtained was compared with that of uncoated aggregate. The aggregates used were a high-surface-area synthetic silica and low-surface-area actual siliceous aggregates; warrior river sand from alabama; and greywackefrom california. The aggregates were precoated with commercial polyamine antistripping agents. The acidic functionalities benzoic acid and phenol demonstrated enhanced adsorption with the antistripping agent precoating, whereas the nonacidic functionalities phenylsulfoxide, benzylbenzoate, benzophenone, quinoline, and pyrene did not. Theadsorption of ac-20 asphalt onto precoated silica and warrior riversand showed decreased adsorption compared to that on the uncoated aggregate. The adsorption of ac-10 on precoated greywacke also showeddecreased adsorption compared to uncoated greywacke. The ranking ofthe ac-20 adsorption on different uncoated aggregates when aggregate surface area was taken into account was warrior river sand > silica > greywacke. Likewise, ac-20 adsorbed more on precoated warrier river sand than on precoated silica. Desorption of ac-20 asphalt from precoated silica using distilled water appeared to be less than thatfrom uncoated silica. This paper appears in transportation researchrecord no. 1269, Asphalt mix materials and mixtures 1990.
Abstract