Before you choose / Nine questions
What the specification still needs to answ
A material label is a beginning. These questions help turn it into a brief that can be checked.
Is lower-carbon concrete the same as sustainable concrete?
No. Climate impact is one indicator. Resource use, water, pollution, durability, safety and whole-life performance also matter. A carbon claim should state its scope and reference.
Is less cement always better?
Not automatically. The concrete must meet the intended performance and service life. Compare suitable mixes and check whether other material demands or construction requirements change.
Our binder chapter separates clinker reduction from the performance questions it still has to answer.
Can I compare two EPD headline numbers?
Only after checking compatibility: product function, declared unit, lifecycle modules, calculation rules, data period and geography. An EPD is not a universal product ranking.
Review what is excluded as carefully as what is reported. A production-only result should not be presented as a complete building lifecycle comparison.
Are alkali-activated materials all geopolymers?
No. Terminology varies, and alkali-activated systems include different chemistries. Ask for the actual precursor, activator, curing regime and performance evidence rather than relying on a category name.
Read the activation chapter for production and acceptance questions.
Does mineralisation make a product carbon-negative?
Not by itself. Measured storage must be assessed alongside capture, transport, energy, processing and the rest of the product system. Carbon origin and accounting rules also affect the claim.
The mineralisation chapter distinguishes storage, avoided emissions and net balance.
Does recycled aggregate replace the binder?
No. It changes the aggregate supply. Binder content and chemistry require a separate assessment, including any mix adjustments needed to maintain performance.
See reclaimed stock for moisture control, traceability and lifecycle questions.
Can these materials be used in reinforced concrete?
Some systems can, subject to appropriate design, exposure-specific evidence, standards and approvals. A generic label or compressive-strength result is not enough to establish suitability.
What should a supplier evidence pack contain?
Request product identity, composition controls, conformity or approval route, relevant performance and durability data, curing instructions, production experience and environmental data with declared boundaries.
Which intervention should a project consider first?
First avoid unnecessary construction and material demand. Then define the performance brief and compare locally available, technically suitable options. There is no universal ranking of the four material routes.