High Friction Surfacing
High Friction Surfacing
WJ Group are the leading UK contractor providing an extensive range of High Friction Surfacing (HFS) surfacing with the experience to recommend and deliver the best solution to meet the specific needs of the client.
HFS affords highway engineers with one of the most cost effective road safety solutions. Designed to reduce braking distances at critical locations, especially in wet conditions, HFS surfacing systems are proven to significantly reduce killed and seriously injured (KSI) accidents.
Origins
HFS was originally developed by the London County Council, the Police and Shell in the 1960s in response to high rates of skid related collisions causing injury and death in London. The first HFS system was based on a 2 component bitumen extended epoxy binder and subsequently named ‘Shellgrip’.
The aggregate selected for use was calcined bauxite because of its unique properties of high polished stone value (PSV), which determines skid resistance, and its extreme hardness, making it more resistant to wear and to polishing through traffic action than any natural aggregate.In the 1990s, performance standards for HFS were established with British Board of Agreement (BBA) certification system and continues to be successfully used today.
‘HFS has been found to reduce wet weather accidents by 57% and could reduce the overall number of accidents on our roads by 5.5%’ – TRL Research – BRF Road fact 1997‘1,700 sites treated in one year with HFS at a cost of £3 million saved us £24 million through accident prevention’ – The London Accident Analysis Unit
Standards
In the UK, CD236 Surface course materials for construction, part of the Design Manual for Roads and Bridges, gives the requirements for the use of surfacing materials.
CD236 defines HFS as ‘specialised high friction surfacing conforming to clause 924 of the Specification for Highway Works (MCHW1)’.
Clause 924 currently requires that both the HFS system and the installer have HAPAS or equivalent product acceptance scheme certification. Certification for HFS systems under the HAPAS scheme operated by the British Board of Agrement (BBA) are available here, whilst the installer requirements under the scheme can be found here.
Our capability
WJ Group companies are certified by the BBA to install several different HAPAS approved Type 1 HFS systems from across the industry. This unique position allows us to select, from a full range of technologies, the most appropriate solution that satisfies your budget, performance, weather and local site conditions.
WJ’s experienced crews install HFS systems nationally delivering essential road safety measures and we are available to provide impartial advice on your best option.
Types of HFS System
There are several different types of high friction surfacing. The main difference is that some systems are applied hot and others at ambient temperatures, leading to the generic terms ‘hot-applied’ and ‘cold-applied’.
Hot-applied systems
Hot-applied systems employ resin binder and a graded blend of calcined bauxite and finer aggregates which are pre-mixed as part of the manufacturing process.
When heated in specialist equipment on site, they become molten, are installed by skilled operatives using the screed method and harden upon cooling.
Contact us for more information and adviceCold-applied systems
Cold-applied systems comprise two or more chemical components including at least one liquid. The components are mixed together and once blended, a cure or hardening process is activated.
This blended binder is applied by squeegee or spray onto the substrate and calcined bauxite aggregate is broadcast onto the wet film, to excess. The binder curing process adheres the aggregate and bonds the system to the surface. Once complete, the excess aggregate can be swept off and is available for re-use.
There are different types of chemistry used within cold-applied HFS systems but the fundamental method of installation is the same.
Contact us for more information and adviceWeatherGrip Type 1
WJ WeatherGrip type 1 is a proprietary HFS system based on modified MMA technology fully complying with the requirements of a type 1 system in accordance with the BBA Certification and the BBA HAPAS Guidelines Document for the Assessment and Certification of High-Friction Surfacing for Highways.
WeatherGrip when used in an appropriate location as defined in the BBA HAPAS Guidelines Document should have a service life of between 5 and 10 years
Contact us for more information and advice