Arnaud Perrot

Title:

Earth and Concrete 3D Printing: Similarities, differences, and shared lessons

Abstract：

Extrusion-based additive manufacturing has become the predominant process for large-scale 3D printing in construction, with concrete materials driving most technological developments and industrial applications. In parallel, earth-based materials have recently attracted increasing scientific interest as a low-carbon and resource-efficient alternative, relying on local raw materials and inspired by traditional construction heritage. Despite their different material natures, both approaches share common process constraints related to filament extrusion, shape stability, and interlayer bond quality.
This presentation introduces earth 3D printing through a comparative analysis with concrete 3D printing, with a specific focus on extrusion-based processes. First, similarities in terms of rheological requirements, printability criteria, and process control are discussed, highlighting shared challenges such as flow behavior, buildability, and geometric fidelity. The presentation then emphasizes fundamental differences in material formulation, dimensional stability, and hardening mechanisms. Concrete 3D printing primarily relies on carefully controlled hydration-driven strength development, whereas earth 3D printing involves physical structuration processes, including thixotropic rebuilding, suction-induced consolidation, and drying-controlled strength gain, sometimes combined with hydraulic or bio-based stabilizers.
These differences lead to distinct curing strategies, early-age behaviors, performance assessment frameworks, and ultimately applications. By contrasting these mechanisms, the presentation illustrates how established methodologies from concrete 3D printing can inform the development of robust earth-printing processes, while earth-based systems also challenge conventional assumptions regarding curing strategies and service-life performance. The proposed comparison aims to foster knowledge transfer between both communities and to contribute to the scientific structuring of digital construction.

Bio:

Arnaud Perrot has been Professor at Bretagne Sud university, France, since 2007. His research topic mainly deals with construction materials rheology and processing. He is co-authors of about 100 publications in international journals and he is an active member of RILEM Technical Committees on concrete 3D printing and Deputy Chair of TC PEM “Processing of earthen materials”. He is also Deputy Editor in Chief of RILEM/Springer Materials and Structures journal.