Fibre-Reinforced Earth-Based 3D Printing: A Review of Mechanical Performance and Environmental Sustainability

Earth-based additive manufacturing (AM) combines design flexibility and automation of 3D printing (3DP) with low embodied energy, local availability, and circular economy compatibility of earthen materials. However, the sustainability performance of earth-based AM remains contested, particularly when chemical stabilisers and fibres are introduced to address mechanical and durability limitations. This review examines earth-based AM, focusing on fibre reinforcement, mechanical performance, and environmental impacts. Following PRISMA guidelines, peer-reviewed open-access articles (2015–2025) were identified and analysed using the Web of Science database. The review synthesises findings on material compositions, processing strategies, mechanical behaviour, and life cycle assessments of 3D-printed earthen materials, with particular attention to natural fibres. Results show that fibre reinforcement primarily contributes to crack control, post-peak behaviour, dimensional stability, and printability rather than universal strength enhancement. Compressive strengths range from 1–3 MPa for non-stabilised printed earth to 6–25 MPa for stabilised systems, confirming stabilisation as critical for structural scalability. Environmental assessments reveal that despite low-carbon feedstocks, 3D-printed earth can exhibit higher carbon emissions than conventional earthen techniques due to binder use and energy-intensive printing unless material savings and circular strategies are optimised. Key gaps include heterogeneous testing protocols, limited structural-scale validation, and insufficient techno-economic integration.