Asfaltslager

Asfaltslager is a layer of asphalt material used in road and airfield pavement construction and maintenance. The term most often denotes the outermost layer, the wearing course, which provides a smooth, skid-resistant surface and protects underlying layers from moisture and wear. In some contexts the term can refer to any asphalt layer within the pavement structure, including base or subbase courses where asphalt is used as a binding or structural layer.

Materials and forms: Asphalt layers are typically asphalt concrete, a mixture of bitumen binder and aggregates such as stone and sand. Variants include dense-graded asphalt for general use, porous asphalt for drainage, and sometimes modified binders or stone-mastic asphalt for higher performance. The choice depends on traffic, climate, and cost considerations.

Construction: The substrate is prepared, including drainage and compaction. Asphalt is heated and laid with a paving machine, then compacted with rollers to achieve target density. Temperature control is critical to ensure proper compaction and minimize defects. Joints between runs are sealed or overlapped to create a continuous surface.

Standards and service life: In Sweden and many countries, asphalt layers are designed and installed according to national and European standards, with specifications for binder content, gradation, thickness, and compaction. The wearing course is designed for load-bearing capacity and friction, while the underlying layers provide structural support.

Maintenance and rehabilitation: Worn asphalt layers develop cracks and raveling; maintenance includes milling and resurfacing, crack sealing, or full reconstruction. Reclaimed asphalt pavement (RAP) can be incorporated into new mixes to improve sustainability.