Betonfahrbahnen werden heutzutage im Wesentlichen auf eine Nutzungsdauer von 30 Jahren ausgelegt. Betrachtet man nun die Betondeckendicke in Abhängigkeit ihrer Belastungsklasse, so stellt man fest, dass eine Verdreifachung der Verkehrsmenge im zugrunde gelegten Nutzungszeitraum zu einer erforderlichen Mehrdicke der Betondecke von etwa 1 cm führt. Mit Einbeziehung von notwendigen Erhaltungsmaßnahmen der Betondecke und weiteren Sicherheitszuschlägen bedeutet dies, dass mit einer Erhöhung der Betondeckendicke auf 35 cm für eine heutige hoch belastete Autobahn eine dreifache Nutzungsdauer möglich ist. Mittels eines geringen finanziellen und materiellen Mehraufwands kann so die Lebensdauer der Betonfahrbahn sowie die Verfügbarkeit der Straße erhöht und vor allem bei den Kosten und Ressourcen deutlich gespart werden. Das trägt maßgeblich zur Nachhaltigkeit im konstruktiven Straßenbau bei.
Concrete pavements – Targeted dimensioning for sustainable development in road construction
Concrete construction methods can be used to create extremely durable and sustainable road surfaces. Service lives of 100 years can be achieved by ensuring sufficient dimensioning and supplementing the required thickness with a generous allowance for measures to improve evenness and texture. If this is applied to today‘s heavily trafficked motorways with current traffic load figures of > 200 million, the dimensioning for a concrete roadway on a 10 cm asphalt base layer would require a concrete pavement thickness of 30 cm. This also takes into account ample safety margins. In addition, an extra 5 cm thickness should be provided for measures to improve flatness and texture. Since these 5 cm are also helpful from a structural point of view, the fatigue of the pavement system will also be much slower in the first decades than with today‘s systems. These two thickness specifications result in a total thickness of 35 cm of concrete pavement during construction for a highly available, economical, resource-saving and extremely sustainable construction method. Compared to today‘s concrete pavements on asphalt base courses, which should also be produced with a grinding reserve and an average thickness of 27.5 cm as required by the German RStO (Guidelines for the Standardisation of the Surface of Traffic Areas), this results in an additional thickness of 7.5 cm for the concrete surface. Assuming material costs for the concrete of an estimated 80 €/ m³, this leads to additional costs of 6 €/m². However, material can be saved in the thickness of the frost protection layer. Assuming material costs for the frost protection layer of 26 €/m³, this results in an amount of 1.95 €/m². In this respect, the additional costs of a concrete carriageway with a thickness of 35 cm compared to current construction methods amount to only around 4 €/m². If this 4 €/m² is compared to the current renewal costs of an estimated 130 €/m² for a typical concrete carriageway renewal project, the additional cost for a traffic area with an extremely long service life is only 4/130, or around 3 %.