A5 and B1 for Ready-Mixed Concrete: What to Do When You Don't Know the Final Use

Ready-mixed concrete producers rarely know how their concrete will be placed, or where it will end up. Yet a cradle-to-grave EPD asks for both. This article explains how the GCCA EPD Tool handles modules A5 and B1 when that information is missing.

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Module A5: construction and installation

Is there a default scenario?

Yes. The tool provides a default A5 scenario for ready-mixed concrete, per cubic metre. It is meant for producers without site-specific data.

What does it cover?

The tool pre-fills these A5 inputs:

• concrete installation losses, set at 3%;
• water consumption and the matching wastewater;
• electricity consumption; and
• diesel for construction machinery.

You can see the current default values on the "A4-5. Construction" screen of the tool. Pumping, placing and compaction are not entered separately. They are covered by the default energy and fuel inputs. Concrete losses follow the same end-of-life scenario as the product itself.

Where do the defaults come from?

The defaults are based on representative background LCA data and industry input on typical installation losses. They are documented in the LCA Model report provided with the tool.

Can I change them?

Yes, but only if you have better data, such as project or regional figures. Any values you enter yourself need to be justified to your verifier.

Module B1: carbonation during use

Concrete slowly absorbs CO₂ from the air during its life. This is called carbonation or recarbonation. The tool models it in line with EN 16757 and offers three approaches.

• Default value (less detailed). For when little or nothing is known about the final use. It relies on default assumptions and is generally conservative.
• Calculation (more detailed). For when the use is known. You enter the service life, the exposed surface per cubic metre and the exposure conditions. If the exposure is unknown, the tool applies a conservative default.
• User-specific recarbonation. You enter a CO₂ uptake value from your own calculation or from an applicable standard or national method.

In the default approach, you only select the type of structure. Service life, exposed surface, exposure and carbonation rate are not inputs. The properties of your concrete, such as its cement content and composition, come from the product description you have already entered. The default approach is intended for elements with a relatively high exposed surface.

Our suggestions when the final use is unknown

• For concrete likely to go into typical building applications, use the default value approach.
• If the exposed surface is likely to be low, or the application is very uncertain, use the user-specific option with the conservative reference values in EN 16757 for your strength class.
• Whatever you choose, describe the A5 and B1 scenarios clearly in your EPD. Your verifier will check that they are realistic for your market.
• If you want to show other scenarios, PCR 2019:14 allows them in a separate results section.

Learn more

For background on carbonation, read Recarbonation of Concrete: From EPDs to Whole-Life Carbon Accounting. To see the tool in action, request a demonstration.