Choosing the right aggregate starts with understanding two closely related, but distinct concepts: standards and specifications. While they are often referenced together, they serve different purposes in defining how materials are classified, tested, and ultimately used in construction.
This overview explains the difference and highlights the most relevant standards and highway specifications for aggregates supplied by Day Aggregates.
What is a Standard?
A standard defines how a material is tested, classified, and verified. It sets out consistent methods for assessing properties such as grading, strength, durability, and composition.
Standards are typically broad and application-neutral, they ensure materials meet a recognised minimum level of quality, regardless of where they are used.
Key Aggregate Standards
Across the aggregates industry, the following British and European Standards are most relevant:
- BS EN 13242 – Aggregates for Unbound and Hydraulically Bound Materials
Covers aggregates used in subbase, capping, and drainage, as well as hydraulically bound mixtures used in civil engineering and road construction. - BS EN 12620 – Aggregates for Concrete
Defines requirements for aggregates used in structural and non-structural concrete. - BS EN 13043 – Aggregates for Bituminous Mixtures
Specifies aggregates for asphalt used in roads, airfields, and other trafficked surfaces. - BS EN 13139 – Aggregates for Mortar
Covers sands and fine aggregates used in mortar, plaster, and screed applications.
In simple terms: Standards define what the material is and how it performs.
What is a Specification?
A specification defines how a material is used in a specific application. It sets out the requirements for performance in a real-world construction context, including placement, layer thickness, and engineering function.
In the highways sector, specifications are primarily set out in the Manual of Contract Documents for Highway Works (MCHW), specifically the Specification for Highway Works (SHW).
Unlike standards, specifications are project- and application-specific.
In simple terms: Specifications define how and where the material is used.
The MCHW and SHW: What’s Changed?
In September 2025, the MCHW was restructured to improve clarity and usability.
Key Changes Relevant to Aggregates
- The traditional SHW “Series” structure has been replaced by a new “CC” numbering system.
- Information is now more clearly organised, with materials and construction requirements consolidated.
- Each clause now addresses a single requirement, reducing ambiguity.
New vs Previous Structure
| SHW Series | New MCHW Reference | Typical Application |
|---|---|---|
| Series 500 | CC 500 – Drainage | Pipe bedding, filter drains |
| Series 600 | CC 601 – Earthworks | Fill materials, capping |
| Series 800 | CC 201 – Pavement Foundation Construction | Sub-base and foundation layers |
What Has Stayed the Same?
- The materials themselves and their performance requirements remain largely unchanged.
- Familiar products such as Type 1 subbase still perform in the same way, even though clause references have changed.
This means customers can continue to specify materials with confidence while being aware that documentation and terminology may differ.
Most Relevant Specifications for Day Aggregates
Day Aggregates supplies materials aligned with key highway applications, including:
Drainage (CC 500)
- Aggregates for pipe bedding, surrounds, and drainage systems
Earthworks (CC 601)
- General and structural fill materials (e.g. 1A, 6N)
- Capping materials (6F1–6F5) used in foundation layers
Pavement Foundations (CC 201)
- Subbase materials such as Type 1 and Type 3
- Hydraulically bound mixtures
- Integrated pavement foundation solutions
Notably, CC 201 now brings together subbase, capping, and foundation design, representing a broader, more integrated approach than the previous Series 800.
Standards vs Specifications: A Simple Comparison
| Standards | Specifications |
|---|---|
| Define minimum material properties | Define application requirements |
| Based on testing and classification | Based on project needs |
| Universal across industries | Project- or sector-specific |
| Example: BS EN 13242 | Example: CC 201 (formerly Clause 803 Type 1) |
Why This Matters to Customers
Understanding both standards and specifications ensures:
- Correct product selection for the intended application
- Compliance with contract requirements
- Confidence in material performance and consistency
For Day Aggregates customers, the key takeaway is simple:
The standards confirm quality, while the specifications confirm suitability.
Even with the 2025 MCHW updates, the materials you rely on remain the same, the main difference is how they are referenced, structured, and specified within project documentation.
