Emulsifiers for Asphalt & Refined Coal Tar
Asphalt and refined coal tar (RT) emulsions are delicate colloidal systems that are dependent on the emulsifier chemistry used for both stability and end-use performance. All applications require the emulsion to remain stable when stored, transported, pumped and mixed, but once applied to the road, it must quickly “break” or separate back into its original disparate oil and water phases. It is when this separation occurs that the road begins the process of developing adhesive and cohesive strength, eventually becoming capable of supporting and withstanding the stresses of traffic loading.
The paradoxical features emulsions must possess can present challenges for emulsion producers and the industry as a whole. Unstable emulsions cost the producer money spent on emulsion reprocessing, tank clean-up, and customer refunds and credits. Emulsions that do not build strength quickly enough after being applied cost the contractor money as a result of reduced production rates, extra traffic control and unnecessary repair work.