Clay-LCA: Clay in Concrete-Environmental & Economic Assessment

Enhancing sustainability in Swedish concrete industry

Cement and concrete industries in Sweden have faced significant pressure and made efforts to enhance their production efficiency while minimizing environmental and economic impacts. One of the promising solutions has been the use of Supplementary Cementitious Materials (SCM), like fly ash. These materials have pozzolanic properties that make them ideal candidates for partially replacing conventional cement in concrete mixes.

Unlocking the potential of local materials

However, the effective use of these materials as cement substitutes relies on factors such as their local availability and technical viability. One of the materials that is available in large amount in Sweden and at the same time is technically feasible to be used as SCM is clay. An ongoing project at RISE has demonstrated that clay can be activated via calcination at temperature of 600°C and serve as a binder combining with Portland cement and limestone in concrete mix.

Aim and Purpose

Our project’s core objective is to determine whether integrating calcined clay as a partial replacement for cement in concrete aligns with circular economy principles and sustainability goals. This entails reducing resource demand, decreasing waste, and mitigating environmental and economic impacts associated with concrete, as an essential building material in construction sector.

Navigating complex challenges

Yet, the journey is not without its complexities. Clay, being a natural resource, requires to be extracted, leading to both economic and environmental consequences. In addition, clay needs to be activated by calcination, which this in turn introduces additional environmental impacts. Unfortunately, a comprehensive environmental life cycle and life cycle cost assessment has not been conducted in Sweden with Swedish data. Therefore, we are bridging this gap through Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) analyses, using Swedish data.  These methodologies help us identify and quantify environmental and economic burdens/benefits caused by extraction, calcination, utilization, and more, as compared to conventional concrete mixes used in Swedish market for infrastructural projects such as bridges.

Obtaining an extraction permit for clay in Sweden is a necessary step due to its natural origins. Therefore, our project explores this process, led by a permit process expert at RISE. We aim to uncover challenges, identify obstacles and various regulations involved.

Furthermore, European harmonized or national standards for quality requirements and application rules are currently absent.  Our project explores the legal and normative framework for implementing concretes with activated clays in Sweden. By identifying obstacles and opportunities, we are working towards defining a roadmap for normative processes.

This project is performing by collaboration between industry and RISE.