| Abstrakt: |
To improve the foaming properties of foamed asphalt and the strength of the cold recycled asphalt mixtures, different types of foaming agents were incorporated for modification. The effects of foaming agent types and contents on the foaming properties, strength and microscopic physical-chemical properties of asphalt mixtures were investigated using asphalt foaming, mixture mechanical properties, electron microscope scanning and infrared spectroscopy tests. The results show that the foaming agent can effectively improve the foaming properties and the mechanical strength of the recycled mix. With the increase of the amount of the foaming agent, all the properties first increase and then decrease. The best solution is to mix the cetyl trimethyl ammonium bromide (CTAB) foaming agent with 0. 5% of asphalt weight. The asphalt expansion rate increases by 21.4%, and the half-life extends by 1. 1 times. The unconfined compressive strengths, dry and wet splitting tensile strength, low-temperature flexural strength of the recycled mix, and failure strain increase by 14.7%, 13.9%, 29. 0%, 27. 8%, and 31. 4%, respectively. The addition of the foaming agent results in a more adequate coating of the aggregate particles by the asphalt film, ad the newly generated chemical functional groups can improve the stability of the foamed asphalt and its adhesion to the recycled asphalt mixtures. [ABSTRACT FROM AUTHOR] |
