Laying of all Asphalt Courses in One Step

Abstract

Typical asphalt pavements consist of two or three asphalt layers which are installed successively. Construction and road closure times could be reduced, if those layers were built simultaneously. As part of the project “Construction Time Reduction by Optimized Asphalt Pavement” concepts were developed to enhance the compact asphalt pavement method in terms of installing thick asphalt layer packages by a single paver passage. For this purpose, a new base/binder course mix AC 45 B/T S was designed that can be installed in thicknesses of 20–22 cm and serve as a base for a simultaneously built, very thin surface course. Furthermore, paving and compaction equipment as well as roadwork processes were adjusted to the new method. First tests on proving grounds have shown paving results that were technically equivalent to conventional asphalt structures. Computational analyses have shown a lower fatigue sensitivity for the structures built by the new method. Paving test tracks on the German federal road B 68 and German motorway A 96 has proven that laying of all asphalt courses in one step is viable even under real site conditions and that it effects a significant reduction in construction time. Although reclaimed asphalt material was used for the base courses of both projects (up to the amount of 60M.-%), most technical requirements were achieved. Evenness turned out to be the only critical factor. Compaction loads on hot and thick layer packages evoke deformations, especially in the edge zones. The stability of the edges has to be improved by the development of new compaction modules.