High Friction (Anti-Skid) Surfacing
High Friction Surfacing (HFS), commonly termed Anti-skid, usually consists of 1-3mm calcined bauxite aggregate (PSV70+ & SRV65+). It is applied to a bituminous surfacing in two ways, as `hot’ applied or a ‘cold’ applied system.
- `Hot’ applied is a thermoplastic resin screed, consisting of a pre-mixed resin binder matrix incorporating calcined bauxite aggregate.
- ‘Cold’ applied is when a ‘scatter coat’ of calcined bauxite aggregate dressing is laid upon a layer of thermosetting resin.
Either buff coloured or mid to dark grey bauxite can be used, however pigmentation is not recommended if wishing to achieve a coloured HFS surface. As grinning/shadow usually results in time within the wheel tracks of the natural bauxite colouration.
N.B.Coloured Traffic Calming, Demarcation/Delineation Surfacing is covered in a separate section.
[Other types of performance proven high PSV aggregates can be used in the ROI]
HFS due to its cost, is installed as directed by the DESIGN MANUAL FOR ROADS AND BRIDGES document `HD 36/06’, in minimum lane lengths of 50m and especially `Table 3.1’ regards specific locations.
[ROI; TII Publications, Surfacing Materials for New and Maintenance Construction, for Use in Ireland; DN-PAV-03023 & Table 4.1 (formerly NRA HD 36/15)]
Northstone is the sole agent in Ireland for Ennis-Flint (formerly Prismo) surface treatments. Ennis-Flint Products have been developed for use on safety sensitive, high stress sites, such as busy junctions, sharp bends, roundabout approaches, pedestrian crossings and accident black spots. They are also used for surfacing pedestrian footbridge decks, approach ramps and stair treads.
Zebraflex® Type 1 (Hot Applied)
A highly durable skid-resistant HFS incorporating a premium grade thermoplastic resin binder and 100% aggregate content of calcined bauxite. Buff or Dark Grey colour available. It is hand applied to provide a 3-5mm thick SRV70+ HFS. Zebraflex Type 1 was the first thermoplastic material to obtain a Type 1 BBA/HAPAS* Roads and Bridges High Friction Surfacing System Certificate No. 00/H043.
*British Board of Agrément/Highways Authority Product Approval Scheme
Typegrip®HFS Type 1 (Cold Applied)
A more durable hand-applied system over Hot applied, also SRV70+ and conforms to the Specification for Highway Works Clause 924 regards a resin bonded HFS. But only laid during April – Sept, pending cold-wet weather and dew in the air as the resin is sensitive to moisture before curing. The system comprises of a two component modified epoxy binder and a specific graded 1-3mm calcined bauxite aggregate (Buff or Dark Grey colour available). It is recommended to be applied to asphalt for optimal results, but can with addition of a seal coat be applied to SMA & asphalt concrete/macadam, or to a suitably brush finished & primed concrete. Installation of the system should only be carried out when the road surface temperature is between 5 to 35°C. The system is BBA/HAPAS approved, Certificate No. 05/H115.
Tyregrip resin may also be pigmented and dressed with natural or pigmented aggregates to provide a decorative stone finish with good slip resistant properties (see the RESIN-BONDED Decorative Surfacing section for full details).Back