Functional Layer Designation of Combined Chip Seal and Slurry Seal in Airport Pavement

With the increasing attention to preventive maintenance and rehabilitation of asphalt pavement, asphalt emulsions have gained popularity. Synchronous chip seal (SCS) and slurry seal (SS) are widely used in pavement preservation due to their low cost and efficiency but are not prevalent in new pavement construction, especially for airport pavement. The objective of this study was to characterize the asphalt emulsions and functional layers of combined chip seal and SS through conventional test methods for asphalt emulsions, asphalt binders, and chip and slurry seals, including setting time, residual amount on sieve of 16 mesh, Engler viscosity, standard viscosity, residue content, penetration, ductility, failure temperature, wet track abrasion test, and load wheel test. Differential scanning calorimetry (DSC) was also conducted to explore the energy differences amongst various emulsions. In addition, trial pavements were also tested in the laboratory and field to evaluate the waterproof performances of the functional layers. The results of material tests showed that SS-1 and SCS-2 were optimum emulsions. The laboratory waterproof test on trial pavement met the requirement of standards and the trial airport pavement emphasized the importance of compaction during construction.