Asphalt Over Concrete
Asphalt overlay is an option for some asphalt surfaces that are in disrepair but paving asphalt over concrete comes with some catches.
Asphalt over concrete. In fact many miles of concrete roads are paved over with asphalt every year. Asphalt lasts 20 25 years while concrete lasts 30 40 years. An asphalt overlay is cheaper to install than replacing concrete and can provide a smooth ride over deteriorating concrete. Concrete itself is very stable and strong so no matter what it is poured over the slab is going to be solid when it hardens.
Homeowners can benefit from this whitetopping technique to reduce labor costs and time when replacing worn asphalt driveways. When concrete deteriorates it draws and holds moisture. However it is important that you understand there are potential side effects and things to watch out for when paving over concrete. Take a look below.
It will however require a little more maintenance than a typical asphalt overlay. Laying asphalt over concrete creates two layers to worry about. But there are issues as you might expect. Unfortunately when asphalt driveways are poured over concrete resting on an unstable base the resulting asphalt pour is prone to instability.
To save time and money many states and municipalities use a road repair technique known as whitetopping the process of pouring concrete over asphalt rather than removing the existing asphalt. Asphalt paving contractors frequently use asphalt over concrete on interstates state highways and city streets concrete provides an excellent base for the asphalt which must have a well compacted stable foundation to yield superior results. Does concrete provide a solid base. Applying an asphalt overlay to a concrete surface is a common practice.
If something is wrong with either of these layers it will show through the asphalt. One positive aspect of installing blacktop over concrete is the concrete provides a firm base for the flexible asphalt paving. Laying asphalt over concrete will likely lead to this new asphalt forming cracks in the same spots that the concrete expansion joints have cracked below. Concrete is a great base material because it is stable and allows for excellent compaction of the asphalt above.
Blacktop can be successfully installed over concrete. This will most commonly occur during expansion and contraction due to heat and or freeze thaw cycles. Therefore concrete is often used as a bridge over unstable ground. The unprepared sub base.
Concrete paved surfaces are not compressed and compacted like asphalt is rather the concrete adheres and fills voids and irregularities with the soil and subgrade beneath it. In addition you do have an alternative paving method that may surprise you. Asphalt requires a well prepared stable subbase otherwise the resulting pavement will be subject to instability and cracking.