Asfaltstabilisering

Asfaltstabilisering is a pavement engineering technique in which existing road materials, such as granular base or recycled asphalt pavement (RAP), are treated with binding agents to improve stiffness, strength and durability. The goal is to create a more load-bearing, moisture-resistant layer that can serve as a stable foundation or, in some cases, as a surface course. Stabilizers include bituminous binders (asphalt emulsion, foamed bitumen, or neat asphalt), cement, lime, fly ash, polymers, or combinations thereof. Stabilization can be performed on site (in-situ) or at a central plant, and typically involves pulverizing the material, adding binder in controlled proportions, and compacting to the desired density.

In-situ stabilization mixes the binder with the existing material directly on the road, often after milling; central plant stabilization produces a managed mix that is transported and placed as a base or subbase layer. Bituminous stabilization is common for weaker subgrades and can serve as a partial replacement for conventional granular layers. Recycling of RAP is a common variant, reducing material waste and resource use.

Design considerations include performance dependence on traffic, climate, drainage, moisture content, gradation, and the chosen stabilizer. Tests such as CBR, resilient modulus, or stiffness assessments help determine optimum binder content and workability.

Advantages of asfaltstabilisering include increased bearing capacity, reduced thickness of new layers, reuse of existing materials, improved moisture resistance, and potentially shorter road closures. Limitations encompass higher initial costs, need for specialist equipment and quality control, curing time for cementitious stabilizers, and the risk of cracking if drainage is poor or materials are poorly matched to loads. It is not suitable for fully saturated subgrades or highly reactive soils.