Semi-rigid surface
The so-called semi - rigid surface (semi - rigid surface layer) or mortared surface is a bitumen-bound floor surface . It is usually installed on an asphalt base course and asphalt binder course instead of an asphalt concrete surface course.
The semi-rigid surface consists of the two components:
- bitumen-bound shoring (e.g. ATG 11 or ATG 16) with a voids content of> 25% and a
- thin, high-strength (≥ 100 N / mm² ) mortar , which was specially developed for this purpose.
When properly executed, the surface combines the flexibility of the asphalt with the strength of the concrete. The binder is shrinkage-compensated and quick-setting. Due to the rapid development of strength , the semi-rigid covering can be used after 12 to 24 hours, depending on the temperature (at approx. 20 ° C ). The compressive strength of the finished covering is approx. 10 N / mm².
The semi-rigid paving is mostly used as a jointless paving for heavy traffic, where conventional asphalt is not sufficient or where the joints in concrete are problematic. It is suitable for long-term loads and for areas of application with very large temperature fluctuations and is resistant to road salt and frost . Usually, only the upper layers of a traffic area are designed in the form of a semi-rigid pavement, since this is primarily intended to increase the resistance to permanent deformation (e.g. development of ruts or impressions from containers). The base layers underneath, on the other hand, are usually designed as asphalt or cement-bound base layers, which results in a “mixed support system” that is specially designed for the respective application.
Semi-rigid coverings can be sanded to give them a terrazzo-like surface. Since semi-rigid pavements are mainly used on heavily used and / or industrially used traffic areas, design aspects play a subordinate role. By grinding, a negative change in the grip of the surface is achieved; it must be tailored to the use.
application
- Bus stops
- Installation areas in front of traffic light systems
- Garages
- Truck parking
- Transshipment points
- Warehouses and workshops
- Airports
- Ports
- similar areas with high demands on the stability of the surface.
The semi-rigid top layer places an increased duty of care on those involved in the construction during planning and production. Since it is a concrete-like surface layer, many well-known principles from concrete construction apply. These are u. A .: do not plan / build triangles, an even, homogeneous installation and adaptation to the ambient conditions (weather, load). Particular emphasis should be placed on aftercare (especially in summer).
Increased grip requirements can be met by surface treatments (shot peening, grinding). Untreated, semi-rigid surfaces are unsuitable for traffic at higher speeds.
Due to the lack of long-term reliability of structures with semi-rigid cover layers, these are not included in the guideline for the standardization of the superstructure of traffic areas (RStO) .
Norms and standards
- Leaflet for the production of semi-rigid top layers
Individual evidence
- ^ Gütegemeinschaft Halbstarre Deckschichten e. V. - What is a semi-rigid top layer - product. Retrieved July 19, 2019 .