Standards Development

Scope

This British Standard specifies requirements for the use of bituminous spray stress absorbing membrane interlayers (SAMIs).

SAMIs act to inhibit crack development in asphalt overlays due to the propagation of cracks from joints or faults in the underlying surface. They are applied between existing surfaces and new asphalt overlays.

NOTE 1 There is a range of different materials and techniques available for SAMIs, including sand asphalt, geosynthetics, and bituminous binders, which can include bitumen emulsion, paving grade bitumen or foamed bitumen.

NOTE 2 PD 6691 gives guidance on the requirements for asphalt which may be used for SAMIs.

NOTE 3 ISO NP TR 18228-10 “Design Using Geosynthetics: Part 10 – Asphalt pavements” gives guidance on design of interlayers with geosynthetics.

Purpose

Currently BS 434-2 written in 2006 has a short paragraph on the installation of bituminous sprays. Since that time new materials and new usages have come onto the market in an uncontrolled way that is not transparent to customers. Other British standards have been produced to replace clauses in BS 434-2 but this clause is still outstanding.

This standard will address both these issues. Quality assurance procedures have become the norm and this standard will support the development of the quality plan to improve consistency between suppliers.