An Essential Guide To Construction Aggregates

Written by| Janine Hughes - Product Manager

Aggregate, is a broad word that describes a “granular material used in construction” (granular meaning particles that do not stick together).

Typically, aggregate material is extracted from quarry sites using heavy machinery, and crushed to produce varying sizes. This can be filtered out by size to be used in various applications that we use every day, from the houses we live in, to the roads we drive on.

What are construction aggregates?

Construction aggregates are simply those hard, granular materials, used specifically within the construction sector. They are the fundamental elements that help build our cities, roads and homes, and form the basis of a number of other construction materials – which could not be made without aggregates.


What are they used for?

The variation of aggregates both in material, source and size, allows for a range of applications. Including:

  • Asphalt for road construction
  • Concrete
  • Precast concrete including paving, bricks and blocks
  • Drainage systems
  • Cement
  • Sub-bases


Outside of construction, aggregates can also be used to produce items such as:

  • Glass
  • Water filtration
  • Ceramics
  • Pharmaceuticals
  • Foundries
Our Aggregate product mix

Read more about our Aggregate mixes 

How are construction aggregates produced?

The Earth formed approximately 4.6 billion years ago. The surface was very hot and when it eventually cooled, the earth’s crust formed. The process of erosion, weathering, chemical and biological action has been happening over the history of the Earth resulting in the formation of rock.


The most common sources of aggregates in the UK are limestone, sandstone and igneous rock. Construction aggregates are then generated through processing these rocks - using extraction, crushing and screening methods - to produce the sizes required.

Extraction – aggregates are first extracted from a quarry using an excavator. Sometimes aggregates can also be extracted from building sites, such as demolished buildings for recycled aggregates.

Crushing – once excavated, the rocks are much larger than the final aggregate needed for construction projects. Aggregate crushing is the process of breaking down the large pieces into smaller particles.

Screening – different sized aggregates are required for different types of construction projects and materials – thus they need separating. Construction aggregates can also be produced from naturally occurring deposits such as sand and gravel.


the different types of aggregate materials

There are four types of aggregates within construction. These are:


Natural aggregate

Natural aggregates, or primary aggregates, are virgin materials that are typically sourced from a quarry or dredged from marine locations. The material has not been subject to anything other than mechanical processing e.g. rock crushing.

This includes crushed rock, sand and gravel.


Secondary aggregate

Secondary aggregates, like Aggneo, are usually by-products of other industrial processes that have not previously been used in construction. This includes both manufactured slag (blast furnace, steel) and naturally occurring aggregates (china clay), depending on their source. China Clay is a virgin aggregate, the surrounding rock (such as a granite deposit) that is excavated to acquire the desired material (china clay) is the secondary aggregate.


Recycled aggregate

Recycled aggregates come from reprocessing inorganic or mineral material that have previously been used in construction. Examples of recycled aggregate include:

  • construction demolition waste (CDW)
  • reclaimed asphalt (otherwise known as RAP)
  • crushed glass
  • spent railway ballast. 


What are recycled aggregates?

In our growing need for sustainable construction, the demand for a circular economy rather than extracting virgin material, is increasing. The use of recycled aggregates provides an opportunity for the construction industry to build sustainably. This could be secondary aggregates through non-industrial processes, or recycled aggregates through construction specific processes.

Circular economy starts by reducing waste. Using a linear approach, circularity can be increased through three principles Reduce, Reuse and Recycle. Within the construction industry, we can learn to build more with less through these principles. Secondary and recycled aggregates offer benefits by providing a Reuse and Recycle option. Giving aggregates a new lease of life once their original purpose has been fulfilled.



In conclusion, construction aggregates come in varying sizes and types, ideal for a wide variety of materials, applications and projects.

The versatility offered by aggregates allows us to design and build roads, public spaces, domestic premises, and buildings that last for generations. Their strength and durability provide opportunities unlike any other widely available resource.

Progression in the production of aggregates has also enabled us to be more sustainable, ensuring full circularity in the construction process. We can do this by creating aggregates from reclaimed asphalt or construction demolition waste, which is reprocessed to create new aggregates for the supply chain.

Frequently Asked Questions

3 Results

Driveway FAQs Asphalt


Answer 1

Driveway FAQs Asphalt

How often should I sweep my asphalt surface?

Sweeping your surface at least once a month will get rid of any debris and help to remove any risk of staining or damage

Is it necessary to fill cracks in my asphalt surface?

Asphalt is a hardwearing material and cracks shouldn’t appear if the product has been installed correctly and not ill-used. For those cases where damage has resulted in a crack, our experts would always recommend repairing it as early as possible before it worsens. In addition, we would encourage you to seek advice from your installer as a crack may indicate a fundamental problem with the installation. In these cases, simply filling a crack may not address an underlying issue.

Can I park my caravan or boat on my asphalt surface?

Asphalt driveways should not be trafficked with heavy vehicles or point loading from heavy objects. Therefore, you should try to park these in a different place or add additional protection appropriate to the load.

How can I protect my asphalt surface during the summer?

During heatwaves, dousing the surface with cold water will help it weather the extreme temperatures.

Frequently Asked Questions on Aggregates

What is Type 1 Aggregate?

Type 1 aggregate, also know as MOT Type 1, is typically used a base layer for highways, pavements, and patios. It is made from different types of aggregates including limestone and crushed concrete, from larger 40mm to granular dust size.

What is Type 2 Aggregate?

Type 2 aggregate is graded from 50mm to finer dust and once compacted, makes the ideal sub-base for both domestic and commercial applications, as well as to fix potholes and as a backfill material.

What is Type 3 Aggregate

Type 3 aggregate is a very popular construction material as the moment with a greater desire for SuDS materials. Type 3 is a 40mm-down product that has been screened to create a reduced fines sub-base and is used commonly as a sub-base for driveways, car parks, paths and many other construction projects where drainage and full permeability is required.

What is coarse Aggregate

Coarse aggregate is any aggregate greater than 4mm in size, including gravels, hardstones and limestones for example.

What is Aggregate Sand?

Sand and gravel material is formed when the parent material has been transported from another location by the flow of water e.g. rivers (fluvial), or ice (glacial) activity forming deposits of natural sand and gravel. The weathering process wears away the softer minerals leaving hard silica rich (quartz) deposits of sand fine aggregate in the same location.

Gravel is composed of various kinds of rock, the most common constituent being the mineral quartz.

What is Aggregate in concrete?

Aggregates, both fine and coarse, constitute about 60 -80% of the concrete formula. Mixed together with cement and water, the aggregate element helps make concrete more compact, provide strength, durability and workability. These properties make concrete one of the most widely used materials across the world. It is used to construct skyscrapers, houses and bridges. Builds cities, connect towns and creates some of the most iconic monuments around the world.

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