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Choosing the Right Type of Aggregate for Your Construction Project
Whether you’re laying a road, or building a house, there is one constant that remains, and that is the need for aggregates.
With various types available used in construction, each offers its own strengths and limitations, but choosing the right types of construction aggregate based on your project is essential.
A slight miscalculation could lead to problems like cracking concrete, unstable sub-bases or unexpected maintenance in a newly constructed project.
At Storefield Aggregates, we have seen how the right choice of construction material can help a project, and how the wrong one can hold it back. We understand that each project has different needs and the choice of aggregate should always be matched to its specific use. In this guide, we’ll walk you through the different types of aggregates used in construction and how to choose the right one for your specific application.
What Are Construction Aggregates?
Construction aggregates, such as sand, gravel, crushed stone, and recycled concrete, form the backbone of most building materials. For example, concrete is usually 60 - 80% aggregate by volume. Beyond concrete, aggregates are also used for drainage layers, road bases, landscaping and even decorative finishes.
The UK construction industry uses millions of tonnes of aggregates each year, and the demand for them is only growing. To meet the net zero 2050 initiative, contractors are also trying out local suppliers and recycled aggregates in their construction projects.
Where Do Different Aggregates Work Best?
If the various grades of aggregates leave you feeling unsure, it helps to look at them in terms of application, understanding which types of aggregates used in construction work best for specific construction needs.
Concrete Foundations and Structural Work
When it comes to concrete mixes, consistency is key. You should choose high-grade coarse aggregates like crushed limestone or gravel (10 to 20mm) as they provide the required strength and help reduce empty spaces. You could also use fine aggregates like sharp sand to fill in any gaps. If you’re constructing load-bearing foundations or slabs, you should choose primary or high-grade recycled aggregates that meet the BS EN 12620 standards.
Sub-Bases and Road Building
Sub-bases require stability and compaction, making Type 1 MOT, made from granite or recycled concrete, an excellent choice with strong load-bearing properties. For working platforms or haul roads, 6F2 or 6F5 recycled aggregates are often preferred for their durability, cost-effectiveness, and reliability.
Drainage Layers
Drainage projects require aggregates with free-drainage properties like single-size gravel or coarse sand. You could also choose recycled aggregates, provided they are graded at a proper facility. For Sustainable Urban Drainage Systems (SuDs), finer materials are required to maintain water flow and prevent clogging.
Asphalt and Surfacing
For asphalt mixes, you need aggregates that bond well with bitumen. Crushed rock and basalt are popular choices for their ability to resist skidding and wear. Recycled aggregates from old asphalt can also be used to cut costs and promote the circular economy.
Primary vs. Recycled: Which Should You Choose?
The main difference between primary and recycled aggregates is that the primary aggregates are quarried, and the recycled aggregates are derived from construction and aggregate products. The quality of recycled aggregates has improved over the last few years, with Type 1 or 6F5 being comparable with virgin stone in certain applications.
The right aggregate for your project depends on its application. High specification structural concrete or applications requiring exact colour and texture may still call for primary aggregates. Factors such as load requirements, drainage conditions, and compliance standards, should all be considered when you’re making this decision.
Aggregate Grading, Size and Shape: Why It Matters
It’s very natural to wonder what the different grades of asphalt mean. The grading of asphalts is based on certain properties like their size distribution, strength, ability to compact, and water absorption.
For example, coarse aggregates are important when you’re providing structure, and finer aggregates are ideal for filling gaps. There are also angular particles available, which help with stability. Choosing the wrong grading, however, can lead to issues such as segregation, poor compaction, or excessive cement use.
Environmental and Sustainability Considerations
There is no doubt that one of the most sustainable construction materials are recycled aggregates. The UK has been working diligently to meet its net-zero goal by 2050, and choosing recycled aggregates supports this effort by reducing the need for quarrying and diverting waste from landfill. Many public contracts now even mandate recycled materials where performance allows.
At Storefield Aggregates, we process demolition waste into certified products like recycled Type 1 and 6F2, meeting WRAP quality protocols. This gives contractors a greener option without compromising on the quality.
Why Choose Storefield Aggregates for Your Next Project
No two construction projects are alike, and neither are the types of aggregates used in their construction. Whether you’re laying a concrete slab, building a farm road, or laying drainage for a housing development, we’ll help you find the right product for the job.
We have over 30 years of experience in the industry, and we provide both quarried and recycled materials. Storefield Aggregates licensed facilities produce high-quality products that meet UK standards, so you can get the job done for the first time.
Planning your next construction project? Contact Storefield Aggregates on 01536 418121 or email info@storefield.co.uk to discuss the best aggregate options for your needs.
