Asphalting in the rain - is that possible?

Again and again it is underestimated how much asphalt companies depend on good weather. What problems would arise when asphalting in the rain, and why rain has equal impact in several areas, read in detail in our post.

Significance of the weather for installation

The weather is crucial when installing asphalt. It is also always taken into account in the planning work directly before installation. An important role is played by 3 factors:

  • Weather (rain / no rain)
  • Outside temperature and
  • Temperature of the underlay (floor temperature)

All three factors also have a significant influence on the degree of compaction of the asphalt.


Asphalt today is still being built "hot on hot" or "hot on warm". The temperature of the individual layers has an important influence on the layer connection and thus on the compaction. The better the individual layers connect, the more resilient the asphalt will be.

The problem is, however, when individual layers cool very quickly. Then the desired connection of the layers can not be achieved, and the required asphalt quality also not.

The working speed can not be increased arbitrarily, since the individual members of the installation chain must work together:

  • the deliverers
  • the pavers
  • the roller drivers

As a rule, even on roads no more than around 150 t / h can be installed. If the outside temperature or the bottom temperature is too low, then the required layer connection can no longer be achieved.

Rain also comes into play here: impinging rainwater would, even at suitable temperatures, cool the layers to such an extent that a sufficient layer connection is no longer possible. The rainwater drips on the hot asphalt and absorbs the heat contained in the asphalt practically completely when evaporating.

Measures in the rain

In most cases, it is not necessary to install the asphalt when it rains. For a reduced layer adhesion and a deviation from the planned compaction, there are today at least in road construction also deductions in the payment, since the life of the asphalt is lower. Therefore, most companies refrain from installing under problematic weather conditions.

Tips & Tricks

But rain is also problematic for the substructure. If a compacted substructure is "rattled off" and only after some time the asphalt pavement comes on the substructure, it may be that the substructure is "too soft". This leads, for example, to the fact that traces of heavy vehicles are clearly visible in the asphalt.

Video Board: Asphalt paving in the rain