Chip Seal Treatment

When selecting an aggregate type and size and binder types, local availability should be considered along with type of traffic. When working in areas where the streets are used by pedestrians, bicyclists, and roller bladers you may want to use a smaller size aggregate.

In order to increase the chances of success of a chip sealing project, a best practice would be to have a short training session before the projects starts with the contractor and agency representative on the project to ensure that everyone is on the same page.

If patching occurs within 60 days before construction, a fog seal should be placed over the patching to seal it off.  If not sealed, rock loss could occur in the area of the patch due to chip seal emulsion soaking into the patch and not being able to hold the aggregate.

Remember, that the design application rate is a starting point and adjustments will need to be made as the surface conditions change throughout the project.

If sweeping is specified right after rolling, it should be a light sweep in order to avoid dislodging aggregate.

Make sure that haul truck wheel paths are staggered when backing up and exercise caution when turning.

Follow the nozzle manufacturer's recommendation for proper nozzle selection.

Rule of thumb is that the spray bar height is 12 inches from surface.

Please note that the embedment depth of the aggregate should be greater in the colder climates due to snow plow damage.  For example, 50% embedment would be satisfactory for Georgia but 70% embedment depth is the goal for Minnesota.

Before taking samples, draw and dispose of 1 gal and then take two 1/2 gal samples.

Temperature, humidity and wind conditions affect the break and cure times for chip seal emulsions.