Microsurfacing

Microsurfacing is a thin, tough layer of asphalt emulsion containing aggregate (rocks), water and mineral fillers. It is used to seal cracks and prevent moisture from penetrating the road base. It is primarily used for preservation of existing hot-mix roadways, which is important as transportation officials look for cost-effective ways to stretch their pavement funding. Typically half a road is closed for microsurfacing at a time. The length of time the road is closed depends on air temperature and humidity and whether one or two passes of microsurfacing is applied. Once this material is applied to the road, plan on approximately an hour delay before it can be ridden or walked on.

This process is often most effective when the existing hot-mix surface is five-seven years old and showing minimal signs of distress. Residents may wonder why a road is being rehabilitated when it appears to be in good condition, but this is the ideal time to do a preservation technique that will further extend the life of the underlying pavement and decrease the maintenance cost over the lifetime of the roadway. If the roadway does exhibit signs of distress, patching and crack-sealing will be done prior to the microsurfacing layer. Microsurfacing is being used on roads throughout Delaware and provides a smoother road surface and less loose material than traditional surface treatment (a.k.a tar and chip). When a road is first microsurfaced, it may present an initial rougher driver surface. This somewhat abrasive surface creates a more skid-resistant surface, thus increasing the safety of the road itself. However, as cars travel over the road, the stones and materials become compressed and smoother, ultimately resulting in a road surface that is nearly as smooth as traditional asphalt hot-mix overlay, but still course enough to improve skid resistance.

The microsurfacing material is also being used to patch rutted roadways in Delaware. The material creates a smoother surface on the road without having to do a large scale and costly asphalt overlay project. In addition, this material is typically applied during daytime hours but can be applied during nighttime hours and on roads with high traffic volumes.