Im Zuge der Umsetzung der Klimaschutzgesetz-Vorgaben gewinnt der Einsatz klinkerreduzierter Zemente im Betonstraßenbau zunehmend an Bedeutung. Bisher wurden diese Zemente vor allem im Unterbeton verwendet, da Zweifel hinsichtlich des Frost-Tausalz-Widerstands bestanden. Ein aktuelles Projekt auf der A9 am Bindlacher Berg zeigt jedoch, dass auch der Einsatz klinkerreduzierter Zemente im Oberbeton möglich ist – ohne Einbußen bei der Leistungsfähigkeit des Fahrbahndeckenbetons. Der Beitrag konzentriert sich auf den Vergleich von Ergebnissen der Erstprüfungen für Fahrbahndeckenbetone mit Portlandzement sowie Portlandkalksteinzement.
Qualification of a road surface concrete using Portland limestone cement
As part of the implementation of the Climate Protection Act, the use of clinker-reduced cements in concrete road construction is becoming increasingly important. Until now, these cements have mainly been used in the base course, as there were doubts regarding their resistance to frost and de-icing salt. However, a current project on the A9 at Bindlacher Berg demonstrates that the use of clinker-reduced cements in the top layer of concrete is also possible – without compromising the performance of the road surface concrete. The test results presented in this article, derived from comparative initial tests carried out as part of the A9 motorway construction project near Bayreuth, impressively demonstrate that a reduction in the clinker content of the top course concrete is possible with CEM II/A-LL, whilst maintaining consistent quality and durability. Both cements tested meet the requirements of the existing regulations. This opens up a promising path for sustainable road construction that meets both environmental and technical requirements. Against the backdrop of the general trend in cement content in Germany, there is further significant potential for decarbonisation in road pavement construction. In future, other alternative, clinker-efficient cements will also gain greater significance in concrete road construction.