Transforming cement production: UK Calcined Clay hits the market
As the construction industry pushes forward with its decarbonisation efforts, LKAB Minerals is pleased to introduce a new product to the UK market: Calcined Clay. Designed to support the transition to lower-carbon construction, this British-manufactured supplementary cementitious material (SCM) offers a reliable, durable and environmentally responsible alternative to traditional cement blends.
Now available on our website, the new product page provides a full overview of the material’s benefits, applications and technical properties. With its potential to replace up to 35% of Portland cement in concrete, Calcined Clay represents a practical, UK-sourced solution for infrastructure, precast and ready-mix concrete producers looking to reduce embodied carbon without compromising on performance.
A British-made cement alternative
Calcined Clay is a finely ground, pozzolanic material produced by heating clay to a high temperature in a controlled environment, then milling it to a precise particle size. At LKAB Minerals, the raw material used in this process is not newly mined but sourced from fired clay bricks that have been diverted from landfill. This allows us to deliver a genuinely circular product, reclaiming value from what would otherwise be considered waste.
By manufacturing this SCM domestically, we reduce the need for long-distance transport and avoid the emissions associated with imported materials. This makes Calcined Clay a meaningful contributor to both carbon reduction and supply chain resilience for UK concrete producers. It is currently the first Calcined Clay SCM manufactured at commercial scale in the UK.
Performance that meets industry expectations
While its environmental credentials are strong, Calcined Clay is also engineered to deliver the technical performance expected by the concrete industry. The product demonstrates good pozzolanic reactivity, meaning it reacts with calcium hydroxide released during cement hydration to form additional calcium aluminate silicate hydrate (C-A–S–H), improving strength and reducing permeability over time.
Its composition also contributes to improved resistance against common durability challenges such as sulphate attack, chloride ingress, and alkali-silica reaction (ASR). This makes it suitable for a wide range of applications, including mass concrete pours and infrastructure where long-term durability is essential.
In addition, when Calcined Clay is blended with CEM I, it extends the setting time, which can be advantageous in warm weather or during the placement of large concrete volumes. This property makes it especially suitable for use in infrastructure, civil engineering, and precast concrete production.
Built for BS 8500-compliant mixes
Calcined Clay supports BS 8500-compliant cement combinations and can be used in both binary and ternary blend systems. It is suitable for use in CEM II/A-Q, CEM II/B-Q, CEM II/B-Q +SR, CEM II/A-M (with limestone) and CEM II/B-M (with limestone) type mixes.
For specifiers, this flexibility opens up opportunities to reduce clinker content in concrete and meet project-specific carbon targets without significantly altering mix behaviour or requiring substantial changes to plant operations.
A circular material for a low carbon future
At a time when clients and regulators are placing increased focus on whole-life carbon, recycled content and responsible sourcing, Calcined Clay offers a route to more environmentally responsible construction without compromising performance. Because it is produced from fired clay waste, the material diverts potential landfill content and eliminates the need for fresh extraction of virgin materials.
Its production and distribution within the UK also contribute to reduced transport emissions, shorter lead times and more resilient supply chains; factors that are becoming increasingly important in infrastructure and commercial development projects. From a procurement perspective, the use of UK-made SCMs can also support local content targets and align with government-backed sustainability frameworks.
Applications and suitability
Calcined Clay is well-suited to a broad range of applications, including ready-mix concrete, precast elements and large-scale pours. Its technical properties make it especially beneficial in scenarios where durability is a key requirement, such as marine and coastal infrastructure, sulphate-bearing soils or chemically aggressive environments.
In addition, the extended setting time offered by Calcined Clay makes it particularly valuable in summer conditions or in large pours where controlling heat of hydration is important. For design teams and engineers working with modern performance criteria and environmental standards, it offers a practical material choice that aligns with long-term carbon reduction strategies.
Technical information and support
Produced under strict quality control processes, the material demonstrates consistent fineness and chemical composition. The clay mineral contains high levels of silica and alumina, minimal free lime or chlorides, and meets the necessary specifications for use in BS 8500-designated cement blends.
For customers, specifiers or technical teams requiring further guidance, our experts are available to discuss mix designs, compatibility testing and project-specific recommendations. We can also provide sample material for trial blends and early-stage validation.
Learn more
To find out more about how Calcined Clay can support your next construction or infrastructure project, visit our dedicated product page or contact your local LKAB Minerals representative. You can also follow us on LinkedIn for the latest updates, case studies, and product releases!
With rising demand for durable, low-carbon construction materials, and increasing scrutiny on sourcing and performance, Calcined Clay provides a timely and practical solution for engineers, contractors and concrete producers committed to responsible construction.
