Superstructure (road construction)
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Superstructure ceiling base course |
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possibly solidified - - - - - - - - - |
Substructure (with dam position) |
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possibly solidified - - - - - - - - - |
Underground | |
The superstructure (also called road paving) forms the uppermost part of the road structure . It is applied directly to the previously created substructure or on the grown subsoil, with the subgrade between the substructure and the superstructure . When producing the superstructure, different building materials and different layer sequences can be used. Basically, a frost-proof superstructure (so-called frost protection construction ) is to be implemented in order to protect the paved traffic area from frost and swap damage. Therefore, depending on the soil and frost conditions, it may be necessary to install a frost protection layer as the lowest layer of the superstructure.
The dimensioning of the superstructure depends primarily on the function of the traffic area and its traffic load. Furthermore, the local location and the soil conditions influence the construction method. These framework conditions allow a classification of various standard construction methods with regard to the load class and the load relevant to the design.
Construction methods
A distinction is made between the following two types of construction:
Superstructure
The superstructure consists of a ceiling (surface course), possibly a binder course and one or more base courses .
Fully bound superstructure
The fully bound superstructure can be made with asphalt or concrete . With asphalt superstructures, the asphalt surface and the asphalt base course are applied directly to the subgrade . The concrete superstructure consists of the concrete ceiling, nonwovens and a base layer with hydraulic binders, which are also applied directly to the subgrade.
Top layers
The following variants are possible as a ceiling:
- Asphalt surface
- Concrete ceiling
- Pavement
- Paving
- Base course
- unbound or water-bound ceiling
Base courses
The base courses are divided into
- Base layers without binders and
- Base courses with binders.
Base courses without binding agents (TOB)
Base layers without binding agents or unbound base layers consist of natural sand, gravel, crushed stone (broken rock) or recycling material (e.g. broken concrete). The layers are compacted and consolidated mechanically using rollers or vibrators, if necessary with the addition of water. There are three types:
- Frost protection layer (short FSS )
- Gravel base layer and water-bound surface with or without sieving
- Gravel base
- Combined frost protection and gravel base layer ( KFT for short )
Base courses with binders (TMB)
Base courses with binders or bound base courses are additionally added to the base course material. Primarily cement or bitumen are used as binding agents. A distinction is made between the following variants:
- Solidification with hydraulic binders
- Hydraulically bound base course ( HGT for short )
- Concrete base
- Drainage concrete base layer
Norms
- Germany: General regulations on the superstructure can be found in the RStO (guidelines for the standardization of the superstructure of traffic areas, 2012). In some regions, however, there are additional and / or alternative specifications from the responsible road construction authorities (civil engineering offices, etc.)
- Austria: Directives and regulations for the road system (RVS)