For the election of the bituminous binder the Strategic Highway Research Program SHRP, a new concept in the USA and Canada has been introduced. Here, the binder is determined by the following temperatures for a particular object
- Maximum temperature of the top layer: the average daily maximum temperatures of the covering of the hottest 7-day period at a depth of 2 cm
- Highest temperature for base courses: average of daily maximum temperatures of the covering of the hottest 7-day period at a depth of 7 cm.
- Deepest first temperature for top and base course: the deepest daily average temperature on the surface measured.
For the USA and Canada the aforementioned critical temperatures were shown in tables, thus, the road builders can make the choice of the bituminous binder, among others due to the climatic data.
In the research project are similar tables for Switzerland developed. Based on 440 stations and taking into account the different climates and the local climatic locations (buildings, forest, bridge), climatic basics for Switzerland is to be drawn up.
A detailed evaluation of the climatic basis for classification of bituminous binders are prepared in accordance with SHRP. There are formed maps of Switzerland, from which the climatic conditions are defined as in the SHRP program can be read out.
Under the Strategic Highway Research Program (SHRP), a brand new approach has been chosen. Faithfully the principle of SHRP ''beyond methods empirical'', the choice of the bituminous binder should result based on the constraints which they will be submitted in the roadway. Thus the requirements of the materials and coatings are determined by the coating conditions of use.
Climatic conditions on an object are important, this is nothing new. However the identification and systematic processing of climate data, and their delivery to the road builders, is a new idea. The purpose of this research mandate is to develop climate data for solicitation high and low temperatures throughout Switzerland, and put at disposal. Under the classification of bitumens according SHRP, information climate must be developed.
Hourly values of the air temperature to two meters above the ground, from weather stations of the Swiss Meteorological Institute ISM, are known to 31 stations. Supported by 64 other stations where hourly values are not known, it has been possible, thanks to a design program for facilities Solar METEONORM, regenerate hourly values for these other 64 stations. Through an interpolation model, the temperatures throughout Switzerland were calculated. During this operation, it was noted that the dependency of the temperature with respect to the altitude above sea level, is very different depending regions of Switzerland. For this reason, Switzerland has been divided into eight climatic regions, for each of which a corresponding interpolation model was developed.
ASTRA Report 473.