Clitheroe
Shap
Horwich, Bolton
Chorley
Horwich, Bolton
Clitheroe
Shap
Horwich, Bolton
Chorley
Horwich, Bolton
Roads, freight yards, airports and railways all place repeated demands on the aggregates within their surfaces and foundations. Heavy loads are just part of the picture, with braking, turning, friction and vibration creating further wear.
Deterioration can begin before the infrastructure even opens. Aggregate may be damaged during compaction or by construction plant, then continue to face traffic and changing weather throughout its service life.
The aim isn’t just to choose the hardest stone. A durable aggregate is one that can retain the properties its particular layer or mixture relies on. This guide looks at fragmentation, abrasion, polishing and weathering, how they’re assessed and what they can mean for long-term performance.
Aggregate durability describes how well a material keeps its physical integrity and required properties during construction and use.
Depending on the application, this may mean resisting crushing, abrasion or polishing. It can also include the ability to withstand repeated wetting and drying, freeze–thaw conditions or chemical deterioration.
Strength tells us how an aggregate responds to an applied load. Durability takes a longer view, considering whether the material can continue to perform as loading, wear and environmental exposure are repeated.
There’s no single durability score that identifies the best aggregate for every project. A road surface, railway track and buried foundation layer each face different conditions, so the properties that matter most will change with the application.
Our guide to how aggregate density and strength affect structural performance looks more closely at how aggregates respond to loading.
Traffic volume only tells part of the story. A steady flow of cars creates different demands from fewer fully loaded HGVs following the same wheel paths.
Vehicle weight, axle loading and frequency all matter. Braking, acceleration and turning create additional friction and sideways forces, while slow-moving or stationary heavy vehicles can concentrate loads in areas such as bus stations, freight yards and container terminals.
Vibration and impact may add further stress. Aggregate can also experience loading from construction plant before the finished road or site has opened.
Water, frost and temperature changes can then act alongside traffic throughout the material’s service life. This means a motorway, bus station and container yard may each need different aggregate properties, even though they’re all high-traffic environments.
Aggregate can deteriorate in several ways. The main risk depends on where the material is used and whether it’s exposed to traffic, weather or loading within the structure.
Aggregate particles can crack or break during compaction, under construction plant or after repeated traffic loading.
When larger particles break into smaller pieces, the grading changes and additional fines may be created. This can reduce interlock, contribute to settlement or fill the voids within a drainage layer.
Fragmentation doesn’t automatically lead to failure. Its significance depends on how much breakdown occurs, where the aggregate is used and how the complete layer has been designed and constructed.
Abrasion happens when friction gradually removes material from the surface of a particle.
It can affect exposed roadstone, railway ballast and aggregate used in heavily trafficked concrete or unbound surfaces. Excessive abrasion may change particle shape, reduce surface texture and produce finer material.
Polishing smooths the surface of an aggregate without necessarily removing much material.
It matters most in road surfacing, particularly at busy junctions, roundabouts and other places where vehicles regularly brake or turn.
As the aggregate becomes smoother, it may provide less wet-weather skid resistance.
Our guide to how aggregate selection affects road and pavement longevity explains this in more detail.
Water can enter the pores of some aggregates. Repeated wetting, drying or freezing may then contribute to cracking or gradual breakdown.
The level of risk depends on the material and its exposure. Aggregate protected within a structure may face very different conditions from stone exposed to water, frost or de-icing salts.
Chemical compatibility may also need to be considered when aggregate is used in concrete.
Find out more about how aggregate moisture content affects material performance.
No single test covers every form of aggregate deterioration. Different methods are used to answer different questions:
| Property being assessed | Common measure | General interpretation |
| Resistance to fragmentation | Los Angeles coefficient | A lower result generally indicates greater resistance |
| Resistance to wear | Micro-Deval coefficient | A lower result generally indicates greater resistance |
| Resistance to polishing | Polished Stone Value | A higher PSV indicates greater polishing resistance |
| Resistance to surface abrasion | Aggregate Abrasion Value | A lower AAV indicates greater abrasion resistance |
| Weathering resistance | Water absorption or specified freeze–thaw testing | Used where moisture and frost exposure are relevant |
BS EN 1097-1 covers the micro-Deval wear test, while BS EN 1097-8 covers PSV.
These results shouldn’t be treated as interchangeable. A high PSV says nothing about how well an aggregate resists fragmentation, just as a low Los Angeles coefficient doesn’t confirm that it will retain skid resistance.
The required tests and performance categories depend on the application. The specifier may need to consider the aggregate’s position, traffic loading, braking and turning, environmental exposure and the consequences of future deterioration.
Not every test is required for every product, and laboratory results can’t predict an exact service life. The applicable product standard and project specification should set out what needs to be assessed and the categories the aggregate must meet.
Descriptions such as “hard-wearing” or the name of a rock type aren’t enough to confirm suitability. Results should relate to the individual source and product being supplied, while grading, particle shape and the rest of the specification must also be satisfied.
Our guide to aggregate testing methods used in UK construction explains how testing supports product selection and quality control.
When an aggregate can withstand the wear it faces, a surface or structural layer can retain its grading, texture and stability for longer. This may mean longer gaps between repairs, cleaning or replacement.
That’s particularly valuable where maintenance involves closing traffic lanes, restricting railway access or interrupting work at a busy industrial site.
There’s no set lifespan for an aggregate. Performance also depends on the design, drainage, binder or cement system, construction, loading and maintenance. Specifying a higher durability category than the application needs may simply add cost without extending its useful life.
Test results are only useful if they represent the material being supplied. Aggregates are natural products, so geology can vary across a quarry. Weathered feed or changes in processing may also affect the finished product.
Representative sampling, testing, clear product identification and Factory Production Control help identify and manage this variation. Once produced, the aggregate must be stored and handled in a way that prevents mixing, contamination and unnecessary particle breakdown.
Read more about quality control in aggregate production.
Matching durability to the conditions the aggregate will face, then maintaining that consistency throughout supply, supports reliable performance in high-traffic infrastructure. Explore Armstrongs’ aggregate range or contact our team to discuss your project.
Aggregate durability is the ability of a material to retain its required properties when exposed to loading, wear and environmental conditions.
Fragmentation breaks particles into smaller pieces, abrasion wears material away and polishing gradually smooths an exposed surface.
Methods may include the micro-Deval test, Aggregate Abrasion Value and Los Angeles testing. The appropriate test depends on the product and application.
Polished Stone Value measures how well a coarse road-surfacing aggregate resists polishing by vehicle tyres. A higher PSV indicates greater resistance.
Yes. If particles fragment under repeated loading, smaller pieces and additional fines can change the particle-size distribution.
Rock type can provide an initial indication, but it doesn’t confirm performance. Test results should relate to the individual source and finished product.
There’s no universal lifespan. It depends on the aggregate, its application, loading, exposure, construction quality and maintenance of the complete infrastructure.
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