Porous asphalt

Porous asphalt is gaining popularity on many markets. The main benefits are less water spray in wet conditions as well as a significantly reduced risk of aqua planning. An additional bonus is a significantly lower tire noise. Reductions of up to 9 dB compared to conventional asphalt has been recorded. Drainage asphalt has a high air void content, often as much as 20 %, which means that is has to be compacted with care. Over-compaction means that the drainage properties are lost and under-compaction will cause premature failure of the pavement. A wearing course of drainage asphalt requires more maintenance than a standard wearing course. It will need cleaning to avoid clogging the drainage channels and will need to be replaced after around five years.  

Joint making and compaction

Joints are the most common point of failure for asphalt wearing courses. The first paved lane will have an unconfined edge where it is difficult to get adequate compaction. Rapid cooling of the asphalt as well as the fact that the asphalt is laterally displaced when compacted causes this phenomenon.  Using an edge compactor on the roller will improve the quality of the joint, it is also important to have enough material to compact when the second lane is paved. If the second lane is too thin it will be impossible to achieve the correct density in the newly paved asphalt.