Glossary of Terms

Aggregate Abrasion Value (AAV)
The standard measure of an aggregates resistance to abrasion.

Backfill
The material used to provide a solid structural base to receive the surface course material and to hold the ironwork, already bedded onto suitable bedding material, in place.

Bedding Mortar
The material used to fix the ironwork frame to the substrate.

Bond Coat
Bond coats are proprietary materials that are PAS approved, generally formulated to enable heavier application rates than are possible with tack coats and to provide greater cohesion between bituminous layers.

CBGM
Cement bound granular material.

CBR
Californian bearing ratio; a measure of load bearing strength.

Composite Construction
A structure where the road is composed of lean mix concrete or other cement bound granular material, normally with bituminous surfacing layers.

Cut-Back
When the width of the reinstatement of the binder or surface course is wider than the reinstatement below to provide higher resistance to water ingress.

Cycle Track
A highway where the public have right of way on a bicycle only.

Deep Openings
All excavations and trenches where the depth of cover over the apparatus is greater than 1.5 metres.

Emergency Works
Works requiring immediate action if deemed to be dangerous to persons or property.

Flexible Construction
The base can be composed of bituminous, granular or a mixture of the two materials.

Footpath
A way over which the public have right of way on foot only, not being a footway.

Footway
A highway also comprised of a carriageway which the public have right of way on foot only.

Frames/Ironwork
Sometimes called street furniture, this term usually applies to manhole covers and gully tops and chambers installed on a road surface.

Geosynthetic Materials
A generic term used when components of a sheet, or structure, are made of synthetic or polymer, and used in contact with soil and other materials in civil engineering applications.

HAPAS
The Highway Authorities Product Approval Scheme is a Product Certification Scheme for the highways sector enabling products not covered by a Standard to obtain 3rd party product certification to provide evidence of performance and service life.

HBM
Hydraulically Bound Materials.

HD
Highway Design standard within the DMRB.

Immediate Reinstatement
Works finished immediately, usually with cold lay material.

Interim Reinstatement
Works finished with temporary materials in need of a permanent reinstatement.

Intervention
When performance standards are not met; the restoration of a poor reinstatement.

L.A.
Los Angeles abrasion value – measure of resistance to abrasion of an aggregate.

Major Projects
Standard works that have been identified and planned at least 6 months in advance of works commencing.

Modular Construction
A structure made up of setts, concrete blocks, brick pavers or paving slabs.

MSA
Million Standard Axles. The number of commercial vehicles that would be occupying the road at the end of the design life of road.

Narrow Trenches
Trenches with 300mm surface width or less, with a surface area greater than 2 metres.

Overbanding
Usually associated with using bituminous or resin based sealants, applied hot or cold to seal narrow cracks or joints usually less than 5mm wide on a road surface. The maximum width is normally less than 40mm.

PAS Approval
Product Accdeptance Scheme Approval. An independent test house which tests, monitors and quality checks materials to ensure compliance to standards.

PCSM
Permanent Cold Lay Surfacing Materials (PCSM’s) are manufactured and laid at ambient temperatures and are used for reinstating around ironwork, utility trenches and filling potholes. These materials remain workable (useable) for several weeks post manufacture, which facilitates their delivery in small loads, tubs and bags which is ideal for hand lay work.

PEN
The penetration grade of a bituminous binder.

Permanent Reinstatement
A repair which has been saw cut into a square, rectangle or diamon, and has properly compacted reinstatement layers up to, and including, finished level.

Permitted
An allowable alternative to the preferred material.

PMMA – Polymer Modified Mastic Asphalt
Mastic asphalt manufactured using a polymer modified binder to impart additional beneficial properties aimed at improving end performance and durability.

Preferred
The favoured choice of all options.

PSV
Polished Stone Value.

PTV
Pendulum Test Value.

Rigid Construction
Usually comprised of pavement quality concrete that has been reinforced.

Road and Footway Structure
Includes the surface course, binder course, base and sub-base.

SHW
Specification for Highway Works – published as volume 1 of the Manual Contract Documents for Highway Works (MCHW).

Small Excavations
All openings with a surface area of 2sqm or less.

SROH
Specification for the Reinstatement of Openings in Highways fourth edition May 2020.

SRV
Skid Resistance Value

Surface Course
The surface course is the very last layer of road construction (prior to markings). It is the part of a road that endures direct contact with traffic.

Stepped Joint
The width of the reinstatement of the binder or surface course is wider than the reinstatement below to provide higher resistance to water ingress.

Street
Any highway, road, lane, footway, alley or passage. Also any square or court.

Tack Coat
Bituminous emulsion used to enhance adhesion or bituminous layers. Tack coat is a sprayed application of an asphalt binder upon an existing asphalt or Portland cement concrete pavement prior to an overlay, or between layers of a new asphalt concrete.

The Act
Refers to the New Roads and Streetworks Act 1991 (NRSWA).

Trim-Line
The cut surface that defines the outer edge of the reinstatement.

Trimback
The area between trim-lines excavated around a fixed feature to permit an adequate reinstatement.

UKAS
National Accreditation Body that has introduced a national scheme for the accreditation of laboratories used for the testing of materials.

Undertaker
Usually the holder of a streetworks license or someone who has a statutory right to execute works.

Urgent Works
Works which fall short of emergency works but require immediate action to prevent further deterioration of a situation.

Wheel Tracking
A test to determine the deformation of surface courses.