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What Makes an Aggregate ‘High Quality’? A Breakdown for Contractors

If you’ve ever faced problems like soft spots in your sub-base or a concrete pour that won’t set right, it’s possible that the quality of construction materials you’re using is to blame. 

You might not realise just how much of a role aggregate quality plays when it comes to your construction projects, and that’s when everything can start to fail structurally. With this in mind, it’s essential that you look beyond the costs and consider other factors, too, when you’re selecting aggregates for your construction projects.

At Storefield Aggregates, we work closely with contractors like you, providing certified materials that meet industry standards and perform reliably on the job. For all our potential contractor partners, we’re sharing a brief guide on what makes a ‘high quality aggregate’, what signs to look for, and why it’s important to work with a reliable supplier like us. 

Why Aggregate Quality Matters More Than You Think

As a qualified contractor, you might already know that aggregates make up around 60 - 80% of concrete by volume. You’re putting your entire structure at risk if you end up using aggregates that are poorly graded or contaminated. 

In the UK, you need to ensure that your aggregates meet British Standards, such as BS EN 12620 for concrete. If you’ve been facing problems like cracking, reduced load-bearing capacity, or poor drainage, it might be time to take a second look at your aggregate supplier.

Understanding Aggregate Types and Their Applications

Once you understand the importance of aggregates, you need a deeper understanding of the types of aggregates used in construction and which is right for you. 

There are three aggregate types, and each has its own applications.

1. Natural Aggregates

Natural aggregates are extracted from quarries or pits. They’re available as sand, gravel, or crushed rock, and can be used in concrete, asphalt, or drainage applications.

2. Recycled Aggregates

The aggregates obtained by processing construction or demolition waste like concrete, brick, or asphalt are known as recycled aggregates. These offer a cost-effective solution for sub-base layers, access roads, or working platforms.

3. Secondary Aggregates

Secondary aggregates come from industrial by-products and are often also called “slag” or “fly ash”. They’re mostly used when projects have certain technical or environmental requirements.

There’s an additional way to classify aggregates, and that’s by size - coarse aggregates (5mm - 40mm) are used in concrete and load-bearing layers and fine aggregates (under 5 mm) are used for mortar, screeds, and for filling voids.

Storefield Aggregates supplies a full range of both quarried and recycled aggregates, which are tested according to industry standards before dispatch.

What Defines High Quality Aggregates?

A standard aggregate used in the wrong place can negatively affect your project, which is why we always stress the importance of using high quality aggregates. 

With that in mind, you’re probably wondering what makes high quality aggregates. Let’s find out.

1. Grading Consistency

High quality aggregates have uniform particle size, which can be confirmed through tests like sieve analysis. A uniform size is essential for proper compaction and bonding in concrete.

2. Cleanliness

These aggregates should also be free from other matter, like silt or clay. A batch of aggregates that hasn’t been cleaned properly will hamper setting time and even bonding strength.

3. Durability and Strength

There are certain tests, such as AIV (Aggregate Impact Value) and ACV (Aggregate Crushing Value), and all aggregates must pass to demonstrate their ability to withstand pressure and load.

4. Shape

It might seem like a minor point, but shape also plays an important role in the quality of aggregates. Angular particles tend to provide better bonding in concrete compared with rounded ones.

5. Moisture Control

A good batch of aggregates shouldn’t retain excess moisture. Moisture could potentially alter the water-cement ratio, leading to inconsistent mixes. There are tests available to determine the moisture quality of aggregates.

If you want to understand more about the quality of aggregates and what suppliers do to deliver the best quality of aggregates, get in touch with our team. 

How to Check the Quality of Construction Materials on Site

If you want to make sure you’re getting high quality aggregates, you don’t need a lab to spot a weaker quality material. There are a few tests you can carry out on your site to check the quality of construction materials. 

Here’s what to do:

1. Visual Inspection

Start by looking for visible dirt or clay to understand the quality of your aggregates. Also look for discolouration or a damp, clumpy texture.

2. Check for Segregation

If your aggregates weren’t handled properly, they might be contaminated with fine, coarse particles, which you’ll need to separate and could potentially lead to uneven mixes.

3. Request Certification

A good supplier will provide you with a declaration of performance and test results for their aggregates. It’s essential to ask for and read through these documents, especially if you’re buying recycled aggregates.

4. Assess Moisture Levels

You could also do a basic squeeze test to determine whether your batch of aggregates has any moisture content. If your aggregates are overly wet, you’ll need to make the necessary adjustments to your mix.

When in doubt, it’s best to talk with your supplier so you can understand the quality of aggregates you’re receiving.

Contact Storefield for High Quality Aggregates 

Even the best construction plan can be undermined by poor quality materials. That’s why, as a contractor, you should always source aggregates from reliable aggregates industries in the UK. These companies are in a position to guarantee that the aggregates will do their job properly.

At Storefield Aggregates, we’ve been supplying natural and recycled aggregates for over 30 years. Whether you’re building roads, laying foundations, or preparing landscaping projects, we provide the fully tested materials you need from our licensed facilities across Northamptonshire.

Our team runs in-house grading and compliance tests, offering rapid delivery through our tipper and grab fleet. Get in touch with our team today by calling 01536 41821 or emailing us at info@storefield.co.uk to discuss your aggregate requirements.