...An Old Product That's New
Asphalt emulsions came into general use in the 1920's, primarily for spray applications and use as dust palliatives. The use of emulsions and range of their applications continuously grow as emulsion and construction technologies are improved. Currently, virtually any paving technique can be done using asphalt emulsions. Choosing the right emulsion and application technique can yield significant economic and environmental benefits.
There are several reasons for increasing interest in the use of asphalt emulsions:
- Energy Savings. Emulsified asphalt does not require a petroleum solvent to make it liquid. (However, some medium-setting grades contain limited amounts of solvent to enhance mixing qualities.) Asphalt emulsions can also be used in most cases without additional heat.
- The ability of certain types of asphalt emulsions to coat damp aggregate surfaces. This reduces the fuel requirements for heat for drying aggregates.
- Availability of a variety of emulsion types. New formulations and improved laboratory procedures have been developed to satisfy design and construction requirements. Polymer modification has allowed the use of emulsions for techniques not previously considered, such as Ralumac® micro-surfacing NovaChip® ultrathin bonded wearing course, RoadArmor® High Performance Chip Seal, EncoreTM emulsion hot in-place recycling and chip seals on high traffic volume highways.
- The ability to use cold materials at remote sites.
- The ability to handle asphalt emulsions at lower temperatures, and the lower flammability of water based materials.
- The ability to increase the service life of slightly distressed existing pavements. Preventative maintenance is a more cost-effective use of highway dollars.
- The ability to recycle. Asphalt emulsions are being used extensively in a variety of recycling systems. They are particularly suited to in-place recycling. Pavements constructed with asphalt emulsions will also be able to be recycled in the future.