The recent interest in 3D printing with concrete has generated great interest on how inhomogeneities arise and affect performance parameters, in particular strength and durability. With respect to durability, of particular interest is how 3D-printed layer interfaces can impact transport of species of interest, such as moisture, chlorides or carbon dioxide in carbonation processes. This is of particular interest considering that the primary use case of 3D-printed concrete has been as a lost formwork for a cast structural concrete, and thus it is of interest to determine the carbonation resistance. This study consists of a preliminary look at the microstructure after accelerated carbonation of a 3D-printed concrete used as a lost formwork. Preferential carbonation is observed in the layer interfaces compared to the bulk of the printed filaments, possibly related to porosity from air voids or a locally high capillary porosity corresponding to the lubrication layer.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9303660 | PMC |
http://dx.doi.org/10.1111/jmi.13087 | DOI Listing |
Nat Commun
January 2025
Chair of Sustainable Construction, Institute of Construction and Infrastructure Management (IBI), ETH Zürich, Stefano-Franscini-Platz 5, 8093, Zurich, Switzerland.
Indoor humidity can significantly impact our comfort and well-being, often leading to the use of mechanical systems for its management. However, these systems can result in substantial carbon emissions and energy precarity. This study offers an alternative: using low-carbon materials that naturally buffer moisture to passively regulate the indoor humidity.
View Article and Find Full Text PDFSensors (Basel)
November 2024
Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011, USA.
This paper explores the development of 3D-printed self-sensing Ultra-High Performance Concrete (UHPC) by incorporating graphite (G) powder, milled carbon microfiber (MCMF), and chopped carbon microfiber (CCMF) as additives into the UHPC matrix to enhance piezoresistive properties while maintaining workability for 3D printing. Percolation curves were established to identify optimal filler inclusion levels, and a series of compressive tests, including quasi-static cyclic, dynamic cyclic, and monotonic compressive loading, were conducted to evaluate the piezoresistive and mechanical performance of 29 different mix designs. It was found that incorporating G powder improved the conductivity of the UHPC but decreased compressive strength for both mold-cast and 3D-printed specimens.
View Article and Find Full Text PDFMaterials (Basel)
October 2024
PowerChina Eco-Environmental Group Co., Ltd., Shenzhen 518102, China.
Three-dimensional printed concrete (3DPC) is increasingly recognized in the construction industry for its high design flexibility and the elimination of conventional formwork. However, weak interlayer adhesion remains a significant challenge. The potential of recycled polyethylene terephthalate (PET) fibers for reinforcing 3DPC is being explored, driven by their environmental sustainability and economic advantages.
View Article and Find Full Text PDFMaterials (Basel)
October 2024
Urban and Environmental Engineering, Building Materials, University of Liège, 4000 Liège, Belgium.
Three-dimensionally printed concrete is a transformative technology that addresses housing shortages due to population growth and enables innovative architectural designs. The objective of this study is to investigate the connection between a conventional test and the rheological properties of 3D-printed concrete. A more precise assessment of material quality based on traditional evaluation techniques is proposed.
View Article and Find Full Text PDFMaterials (Basel)
October 2024
Materials and Chemistry Unit, Flemish Institute for Technological Research (VITO), 2400 Mol, Belgium.
The valorisation of sludges from aggregate production into construction materials is required for full circularity in mining waste management. This study explores valorisation pathways, relevant regulatory frameworks, and End-of-Waste (EoW) criteria for specific settings in Spain and Norway. The explored valorisation routes involved the production of filler, supplementary cementitious materials (SCMs), and lightweight aggregates (LWAs) for the production of cement-based products, and precursors for 3D printed construction material.
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