Adaptation of road infrastructure to climate change

Project 5
Study to review standardised asphalt pavements under changed temperature boundary conditions
Source: Federal Highway Research Institute (BASt)


Asphalt displays elastic-plastic-viscose characteristics that are highly temperature-dependent. During asphalt pavement construction, the chance of cracks forming at low temperatures as well as permanent malformations in ruts due to high temperatures has to be taken into consideration. Unilateral optimisation of asphalt composition mostly ends up in reduced performance in terms of each of the contradicting temperature ranges.

The currently used types of asphalt with their individual layer thicknesses are the result of decades of experience gathered in the use of this material. With careful construction, the desired lifespan of a road can be insured in terms of today’s temperature spectrum. What is still uncertain, however, is by which means the current road usability periods can be attained if the temperature range is increasing due to climate change.

Therefore, an investigation following the „Guidelines for the mathematical dimensioning of the superstructure of road surfaces with asphalt paving" (RDO Asphalt) has been carried out to explore up to which increase of the annual mean temperature and traffic development the standard asphalt designs and dimensioning can be used to reach the usual road usability periods.


Climate model data from the Federal Environmental Agency (Model: REMO) was used to calculate to which extent standardised asphalt pavements could attain the planned term of use, even under changing temperature conditions. This data was entered into a thermal bal-ance equation in order to determine surface temperatures of carriageways. At the same time, emerging traffic burdens on carriageway construction were integrated within the calcu-lation as a dimensioning -relevant parameter.

Finally, standardised asphalt pavements were tested according to RStO / ZTV Asphalt with findings from RDO Asphalt 09 on the basis of temperature and climate parameters.


Emerging climate changes only have a minimal impact on routes that have a term of use ending before 2050, meaning there is no course of action necessary. In terms of carriage-ways that have a planned term of use extending beyond this period, a significant reduction is to be expected if the usual, current dimensionings continue to be implemented. Using higher quality asphalt, in particular regarding properties in high temperatures, should be taken into consideration.

It can, on the whole, be confirmed that the constructions carried out in the years to come and dimensioned in compliance with RStO will be still sufficient. However, in the long-term, adaptation to increasing temperatures will be necessary. Due to the fact that constructions have a greater forerun period and roads have an anticipated term of use amounting 30 years, there will already result a need for action within a few years.

Project data


Term of project: 01/02/2012 – 28/11/2014

primia GmbH

BASt unit Z5
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