On 1 January 2008 the existing British Standards for asphalt paving (BS 4987-1 and BS 594-1) were withdrawn and replaced by a new European Standard in several parts:
- BS EN 13108:— Bituminous mixtures, material, specifications
- BS EN 13108–1 Asphalt concrete
- BS EN 13108–2 Asphalt concrete for thin layers
- BS EN 13108–3 Soft asphalt
- BS EN 13108–4 Hot rolled asphalt
- BS EN 13108–5 Stone mastic asphalt
- BS EN 13108–6 Mastic asphalt
- BS EN 13108–7 Porous asphalt
- BS EN 13108–8 Reclaimed asphalt
- BS EN 13108–20 Type testing
- BS EN 13108–21 Factory production control
Products typically used by UK specifiers, and covered in NBS work section Q22, are asphalt concrete (formerly macadam), hot rolled asphalt and stone mastic asphalt (mainly laid in the UK as proprietary systems under the BBA HAPAS approval scheme). The products covered by other parts of this standard are typically used in other member countries of the EU.
The transition to the new standard will be eased by the publication by BSI of PD 6691:2007 Guidance on the use of BS EN 13108 bituminous mixtures – Material specifications. This document provides guidance on specification to the new standard based on the requirements of the old standards.
Although the products traditionally used in the UK asphalt industry will still be available under the new European Standard, the terminology describing these products is changing. Macadam, used widely throughout the UK, will now be called asphalt concrete (AC). The binder penetration designation previously expressed as a single number will now become a range e.g. 125pen will now be referred to as 100/150. Product descriptions will now be generally structured by mixture, aggregate size, use and penetration range, e.g. Asphalt concrete with a maximum aggregate size of 10 mm for use as a surface course with 40/60 penetration bitumen will be ‘AC 10 surf 40/60’. For further details on product designations see annexes B, C and D to PD 6691.
The introduction of the new European standard includes a significant improvement with the addition of specific provision for the specification of reclaimed or recycled asphalt in part 8. Currently the recycling of asphalt is common, and is encouraged in the Highways Agency Specification for highway works, but there has never been provision for it’s use in the old standards. PD 6691 recommends a max. 10% recycled content in surface courses and 50% in base and binder courses.
As in all new ENs, the new standards include the requirement for the supplier to issue a declaration of conformity with a CE mark. The two parts of the conformity procedure are covered in parts 20 and 21 of the standard but the requirement to comply with these conformity standards is included in each of the parts of BS EN 13108.
January 2008 also saw the introduction of a new standard for the transportation, laying and compacting of asphalt. BS 594987 replaces BS 594-2 and BS 4987-2. A full revision of the Highways Agency Specification for highway works is also in progress.
Changes to NBS worksection Q22 are currently being incorporated and are included in update 2008-1, March 2008. In the interim, PD 6691 annexes B, C and D will provide valuable guidance to specifiers on how to specify the new products in accordance with BS EN 13108.