A Reflection on Sustainable Opportunities for 3D Printing in Construction (2023-06)¶

Building and Construction activities are among the most responsible for negative impacts on ecosystems and biodiversity due to unmeasured extraction and consumption of raw materials/natural resources, followed by significant waste production. Few strategies have been implemented to minimise these harmful effects, some of which relate to the conscious choice of more durable and sustainable materials, the reuse or recycling of resources or savings of energy and water during the buildings’ life cycle stages. Several automation-oriented processes have been created and developed to surpass conventional construction methods' low sustainability, with 3D printing (3DP) emerging as a strong contender. Based on the controlled layer-by-layer material deposition, this automated production process allows complex and customised design. It provides a quick construction method without precast, reducing human resources and material waste, thus improving the sector’s sustainability. However, mortars developed for 3DP have Portland cement as the preferred binder, a material that entails high carbon emissions and energy consumption during its manufacture. In this regard, the present work seeks to present and discuss the current trends of 3DP in Construction, particularly the possibility of integrating or partially replacing binders or aggregates in extrudable mixtures with more sustainable ones (such as Construction and Demolition waste). Finally, several examples that quantitively evaluate the environmental benefits of this technology through Life Cycle Assessment (LCA) were reviewed and discussed to better assess possible improvements during any of the building’s life cycle stages.