Like any profession, pavement engineering comes with its own terms and phrases. If you're working in this area, it's important you understand it all; otherwise, you run the risk of making mistakes that can take time and money to rectify.
To ensure you're fully up-to-speed and that you're not caught out by any paving terms, we've compiled this guide.
What is pavement engineering?
First, let's understand what a pavement engineer is and what they do. Pavement engineering is a branch of civil engineering. The job requires knowledge of soils, hydraulics and how materials react to different loads or weights.
Pavement engineers work on pavements, roads, car parks, driveways or garden paths. Basically, any ground that people can cross.
To effectively create paved areas, engineers need to consider the function of the pavement, its loading demands, the local geography, and budgetary restraints to design a surface that can match the demands that will be placed on it.
Managing these factors and ensuring the pavement's composition is adequate requires great attention to detail and specific knowledge of materials.
42 pavement engineering terms you need to know
Asphalt
- A street paving material made of bitumen and mineral aggregate (such as sand or stone dust). It makes up the large majority of all urban paved surfaces
- The black, viscous form of petroleum, found in natural deposits or made by refining, is used in making the paving material. Commonly known as tarmac or blacktop
Asphalt chip sealing
A layer of aggregate rolled into a base of asphalt emulsion binder improves tyre grip and road wear and can alter the reflectivity of the surface. Using light-coloured aggregates can increase reflectance, reducing warming.
Additionally, locally sourced aggregates can help match the surrounding area and its character or aesthetic.
Base (Road-base)
One or more layers of material placed above the sub-base that constitutes the main structural element of a pavement on which the laying course is placed
Belgian block
Rectangular or cube-shaped natural stone paving unit, also known as setts.
Bitmac
Made from bitumen and macadam, it is primarily used as a basecoat or layer for road surfacing. Although it is not as durable as asphalt, it is less expensive.
Bitumen
Bitumen, sometimes called 'tar' or 'pitch,' is a petroleum-based hydrocarbon. It is used as a binder and is combined with aggregates to create a top-wearing road surface. Bitumen is obtained from crude oil, forming a residue after the distillation process.
Block (concrete)
A block is a paving small element paving unit manufactured from precast concrete that satisfies the following conditions:
- a) at a distance of 50 mm from any edge, any cross-section does not show a horizontal dimension less than 50 mm.
- b) its overall length divided by its thickness is less than or equal to four.
Bound surface construction
A rigid pavement construction where the paving units are laid on and jointed with a cementitious mortar
Capping
Layer of material used to improve or protect the subgrade
Causeway
A raised road or path across water or low-lying land, sometimes including flood arches.
Cobble
A natural stone paving unit rounded by erosion, being between 63 mm and 200 mm in diameter.
Cobbled
Cobbled is a modular pavement paved with natural stone cobbles.
Cube
A cube is a square-shaped sett used on roads, footpaths and other walkways.
Dense Bituminous Macadam (DBM)
A material commonly used as a continuous surface course for roads or driveways and can also be used as a base material.
Dropped kerb
A short stretch of pavement that has been lowered to allow vehicles to drive across the pavement and park in driveways. It can also mean lowering a section of pavement to let people in wheelchairs or buggies cross the road.
Dropper kerb
The type of kerb stones required to create a dropped kerb.
Flags
Larger element paving units manufactured from precast concrete. The maximum length for flags is 1m, and the length divided by thickness is greater than four.
Flag paving tends to have a larger surface area and is more suited to pedestrian areas or lightly trafficked areas. A concrete paving unit becomes a flag once it exceeds the definitions of a block.
Foundation
Lower layers of the pavement consisting of the sub-base and, if used, the capping
Granolithic paving
A screed material composed of cement and aggregates such as limestone, granite and even old building materials. It gives all the strength and durability of concrete with a much smoother walking surface.
Joints
An area connecting two vertical adjacent units (excluding nibs featured) or between a paving unit and edge restraint
Jointing material
A material applied to fill a joint which may be structural or non-structural
Kerb
The edge of a pavement is often marked by a kerbstone, a line of kerbstones where footway and carriageway meet. Kerbs are often raised above the level of a roadway to increase pedestrian safety.
Laying course
The layer of material on which paving units are installed, laying course materials for an unbound construction should contain nothing which acts as a binder and/or could detract from the flexible nature of the pavement, e.g. cement, lime, bitumen or resin. The laying course material should be free-draining, clean, hard and durable, containing no deleterious materials such as wood, plastic or soil.
The laying course materials for a bound construction should be a cementitious mortar which should be a blend of fine aggregates and a cementitious binder. A Type 25 or Type 35 bedding mortar may be used depending on the construction method.
Laying/bond pattern
The arrangement of paving units to form specific patterns for either structural requirements or visual effect.
Ledger
Ledgers are flat stone slabs that are typically made from granite, marble or sandstone and can be inscribed.
Macadam
- A type of road construction with a smooth, hard surface in which layers of compacted, crushed stone are bound with stone dust
- A similar type of road construction but with the addition of tar as a binder. See also bitmac and tarmac
Metalled road
A metalled road is one surfaced in 'road metal,' which is what the crushed rock that was used to seal and waterproof road surfaces was known as. This technique was pioneered by the engineer John McAdam.
Modular pavement
A pavement having a surface course comprising of paving units with joints between them.
Movement joint
A designed break in the pavement structure to allow the pavement to expand, contract or flex
Pavement
Any paved area subject to pedestrian and/or vehicular traffic
Paver
A manufactured or naturally occurring unit used to form the surface course of a modular pavement also known as a paving unit.
Pebble paving
Pavement structure that has been made from pebbles set in cement or another binder.
Permeable pavement
A permeable pavement is constructed from either a continuous porous material that enables rainwater to flow through it or more commonly non-porous blocks that are specially designed and manufactured to allow water to flow through the joints and into the sub-base where the water is stored and attenuated before it disperses at a controlled rate either into the ground below or via a discharge pipe.
Sand joints
Jointing sand is a material commonly placed between block paving units within an unbound construction and creates frictional interlock between adjacent paving units.
Scoria block
A particularly durable and robust block, used for building and paving, made (from the eighteenth century onwards) from scoria (the residue of metal-smelting processes).
Sett
Small element paving units are formed using natural stone by cutting or splitting it. The length must not exceed twice the width, and the width must not exceed twice the thickness. Typically used in a bound construction and designed to take moderate levels of traffic.
Slab
Larger element paving units formed from natural stone by cutting or splitting in which the width exceeds two times the thickness.
Typically used in a bound construction and designed to take moderate levels of traffic.
Stable-block paver
A durable paving brick indented with a grid of lines to shed liquid and provide a good grip.
Standard axle
A metric used to describe trafficking for the purpose of pavement design in the UK based on the typical load applied by a standard HGV axle of 8200kg or 80kN. The axle load of a wheeled vehicle is the total weight bearing on the roadway for all wheels connected to a given axle.
Sub-base
The layer of material placed above the subgrade or capping (if used) which distributes the loading from the upper pavement layers down to the subgrade
Sub-grade (grade)
The ground the paving, walkway, or roadway is being built on.
Race
Fresh concrete foundation for kerb lines
Tactile paving
Tactile paving is the term given to paving units that bear a distinctive, raised surface profile such as ‘ribs’ running across the paving, or ‘spots’ that create a bumpy surface to be detected by both sighted and visually impaired pedestrians. Tactile paving is commonly found at roadsides such as crossings, by and on flights of stairs, and on station platforms.
Tarmac
- A generic name for asphalt surfaces
- A patented type of road-surfacing material composed mainly of compacted tar and aggregate. The word is a shortening of tarmacadam, a word combining tar with the name of the engineer and road-builder John McAdam, who invented a process for building roads with a smooth, hard surface.
Unbound surface construction
A pavement construction where the paving units are laid on and jointed with selected unbound aggregate, sometimes referred to as flexible surface construction.
Plan your next commercial project with Marshalls
Now that you know the key terms and phrases, you'll be ready to ensure that the paving provisions on your next project are compliant and of high quality.
Remember, if you're unsure which type of bricks, paving, or drainage system is best for your project, you can contact our team of product experts to help you make the most suitable choice.
For more advice and information, check out the Marshalls Commercial Blog.
Here, you'll find expert insight on maintaining an ethical and accountable supply chain, navigating urban flood management, and the regulations relating to tactile paving.