Reuse of excavated soil in 3D printing of sustainable earth-based mixtures for low energy buildings

Project Information

RePrintCLAY

Grant agreement ID: 101068760

DOI

10.3030/101068760

Project closed

EC signature date 18 July 2022

Start date 1 September 2022

End date 30 September 2024

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 211 754,88

Coordinated by

UNIVERSITE DE BRETAGNE SUD
France

Periodic Reporting for period 1 - RePrintCLAY (Reuse of excavated soil in 3D printing of sustainable earth-based mixtures for low energy buildings)

Reporting period: 2022-09-01 to 2024-09-30

Summary of the context and overall objectives of the project

The project focuses on developing sustainable 3D-printable earth mixes by utilizing excavation waste, paving the way for environmentally responsible construction practices. The construction industry faces significant challenges, including resource depletion, high carbon emissions and excessive construction waste generation. Additionally, the industry inherently suffers from a shortage of skilled labour, making automation an imminent necessity. This project addresses these challenges by revalorizing excavation waste into a viable, printable construction material, contributing to the circular economy and promoting sustainable building solutions with automation potential.
The primary objective of the project was to develop and optimize low-carbon earth-based mixes utilizing waste streams and byproduct resources, making them suitable for additive manufacturing. Through a series of experimental investigations and sustainability assessments, the project aimed to achieve a balance between printability, mechanical performance and environmental impact. Key challenges addressed included optimizing mix compositions, enhancing mechanical properties and validating printability using industrial robotic systems.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The project's approach was structured into five work packages, covering material characterization, mix optimization, mechanical performance evaluation, environmental sustainability and real-world application through full-scale 3D printing trials. The research led to the identification of an optimal activator system consisting of Sodium Silicate and Sodium Carbonate, in combination with Ground Granulated Blast Furnace Slag (GGBS) as a binder which satisfied the required properties for both fresh and hardened states. The developed mixes exhibited promising mechanical strength, durability and printability, making them suitable for practical applications in construction. Another significant aspect of the project was the evaluation of the environmental performance of the developed materials through a comprehensive Life Cycle Assessment (LCA). This assessment provided valuable insights into the carbon footprint and resource efficiency of the developed materials, ensuring that they meet sustainability benchmarks. Additionally, the potential of these mixes to regulate indoor climate conditions was explored by measuring their Moisture Buffering Values (MBV), which assess their ability to contribute to occupant comfort in buildings.

Key Achievements and Expected Impact
The project has resulted in several key outcomes that contribute to the advancement of sustainable construction technologies:
1. Development of optimized low-carbon earth-based mixes with enhanced printability and mechanical performance.
2. Successful 3D printing trials demonstrating scalability and feasibility for real-world applications.
3. Sustainability validation through LCA studies ensuring alignment with environmental goals.
4. Knowledge dissemination and capacity building achieved through conference presentations, teaching engagements and scientific publications.
5. Potential societal impact as the developed materials offer a sustainable alternative for housing and infrastructure with the possibility of enhancing indoor climate through moisture regulation.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The project’s results have been widely shared with the scientific community and industry stakeholders through participation in international conferences, seminars and anticipated publications in leading scientific journals. The ongoing collaboration with academic institutions and industry practitioners ensures that the findings will continue to contribute to future research and practical implementation in sustainable construction.