Performance evaluation of polyamine anti-stripping additives

Polyamine anti-stripping additives in asphalt mixes are chemical chains that bond chemically with an acidic siliceous aggregate at one end and an asphalt binder at the other. They help to prevent the hydro-oxide of siliceous aggregates from reacting with water molecules, which can lead to a breakdown of the asphalt mix. The effect of two proprietary polyamine-based anti-strippers, Wetfix and Tackamin-200, on moisture susceptibility, the resilient modulus and rutting performance were evaluated at percentages from 3 to 6% with increments of 0·1%. Wet and dry indirect tensile strength, the indirect tensile resilient modulus and dynamic creep tests were used to assess the moisture susceptibility, structural response and rutting resistance of treated asphalt mixes. The results indicated that 0·5% was the optimum dosage for both additives with respect to all performed tests, with Wetfix being more efficient. Overall, it was found that the impact of the anti-stripping agents on moisture susceptibility was significant.