{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T07:14:58Z","timestamp":1774422898914,"version":"3.50.1"},"reference-count":59,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T00:00:00Z","timestamp":1774224000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Science Foundation","award":["#2115169"],"award-info":[{"award-number":["#2115169"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Buildings"],"abstract":"<jats:p>The advancement of sustainable construction requires the development of earthen materials compatible with 3D printing (additive manufacturing), along with specified engineering standards. Many existing studies improve workability and early strength using chemical stabilizers such as cement; however, these additives increase embodied carbon and undermine sustainability objectives. Challenges remain in the formulation of an earthen mixture that satisfies both printability and structural requirements for large-scale construction. Previous earth-based mixes have reported excessive shrinkage and inadequate compressive strength. This study presents the systematic optimization of a low-carbon, 3D-printable earthen mixture using locally sourced clay-loam soil from Bel\u00e9n, New Mexico (NM). The soil was modified with graded concrete sand and rice hull fiber to improve printing parameters such as buildability, extrudability, and printability while meeting the NM Earthen Building Code requirements for compressive and flexural strength. Soil characterization tests (particle size distribution, consistency, optimal water content) guided iterative refinement to enhance dimensional stability and mechanical performance. A baseline 2:1 soil-to-sand ratio (max aggregate size No. 4) was established. Incorporating 2% rice hull fiber and reducing max aggregate size to No. 16 (S67F2) early-age shrinkage was reduced from 12.33% to 3.48% (72% reduction) while maintaining a 28-day compressive strength exceeding 660 psi, more than twice the code minimum. The optimized mixture supported 24 printed layers without deformation, achieved 189 psi flexural strength (three times the code minimum), and produced a stable 2-ft-diameter dome with minimal cracking.<\/jats:p>","DOI":"10.3390\/buildings16061261","type":"journal-article","created":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T09:48:42Z","timestamp":1774259322000},"page":"1261","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["3D Printing of Earth-Based Mixtures: Linking Material Design, Printability, and Structural Performance"],"prefix":"10.3390","volume":"16","author":[{"given":"Daiquiri","family":"Zozaya","sequence":"first","affiliation":[{"name":"Department of Municipal Development, Albuquerque, NM 87102, USA"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-0268-1133","authenticated-orcid":false,"given":"Hamideh","family":"Shojaeian","sequence":"additional","affiliation":[{"name":"Gerald May Department of Civil, Construction, and Environmental Engineering, University of New Mexico, Albuquerque, NM 87106, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4077-3588","authenticated-orcid":false,"given":"Francisco","family":"Uvi\u00f1a-Contreras","sequence":"additional","affiliation":[{"name":"School of Architecture and Planning, University of New Mexico, Albuquerque, NM 87106, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6043-7173","authenticated-orcid":false,"given":"Maryam","family":"Hojati","sequence":"additional","affiliation":[{"name":"Gerald May Department of Civil, Construction, and Environmental Engineering, University of New Mexico, Albuquerque, NM 87106, USA"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,23]]},"reference":[{"key":"ref_1","first-page":"2050005","article-title":"Global diffusion of innovation during the fourth industrial revolution: The case of additive manufacturing or 3DP","volume":"17","author":"Steenhuis","year":"2020","journal-title":"Int. J. Innov. Technol. Manag."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"922","DOI":"10.1111\/puar.12988","article-title":"The next industrial revolution? The role of public administration in supporting government to oversee 3DP technologies","volume":"76","author":"Dickinson","year":"2018","journal-title":"Public Adm. Rev."},{"key":"ref_3","unstructured":"Rodrigues, H., Gaspar, F., Fernandes, P., and Mateus, A. (2021). Additive manufacturing of architectural structures: An interplay between materials, systems, and design. Sustainability and Automation in Smart Constructions, Springer."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"105417","DOI":"10.1016\/j.autcon.2024.105417","article-title":"Towards innovative and sustainable buildings: A comprehensive review of 3DP in construction","volume":"163","author":"Hassan","year":"2024","journal-title":"Autom. Constr."},{"key":"ref_5","unstructured":"Hojati, M., Nazarian, S., Duarte, J.P., Radli\u0144ska, A., Ashrafi, N., Craveiro, F., and Bil\u00e9n, S. (2018, January 10\u201313). 3D Printing of Concrete: A Continuous Exploration of Mix Design and Printing Process. Proceedings of the 42nd IAHS World Congress, Naples, Italy."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"130630","DOI":"10.1016\/j.jclepro.2022.130630","article-title":"Digital manufacturing for earth construction: A critical review","volume":"338","author":"Gomaa","year":"2022","journal-title":"J. Clean. Prod."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Li, Z., Hojati, M., Wu, Z., Piasente, J., Ashrafi, N., Duarte, J.P., Nazarian, S., Bil\u00e9n, S.G., Memari, A.M., and Radli\u0144ska, A. (2020). Fresh and hardened properties of extrusion-based 3D-printed cementitious materials: A review. Sustainability, 12.","DOI":"10.3390\/su12145628"},{"key":"ref_8","first-page":"10004","article-title":"3DP technology for rapid response to climate change: Challenges and emergency needs","volume":"1","author":"Rashid","year":"2024","journal-title":"Int. Stud. Manag."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Ibrahim, I., Eltarabishi, F., Abdalla, H., and Abdallah, M. (2022). 3DP in sustainable buildings: Systematic review and applications in the United Arab Emirates. Buildings, 12.","DOI":"10.3390\/buildings12101703"},{"key":"ref_10","unstructured":"Zeiher, L.C. (1996). The Ecology of Architecture: A Complete Guide to Creating the Environmentally Conscious Building, Whitney Library of Design."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"106782","DOI":"10.1016\/j.isci.2023.106782","article-title":"Growing role of concrete in sand and climate crises","volume":"26","author":"Watari","year":"2023","journal-title":"iScience"},{"key":"ref_12","unstructured":"Bryson, Z., Kawashima, S., and Ben-Alon, L. (2022, January 7\u201323). Towards 3D printed earth- and bio-based insulation materials: A case study on light straw clay. Proceedings of the 18th International Conference on Non-Conventional Materials and Technologies (NOCMAT 2022), Virtual."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"670","DOI":"10.1016\/j.conbuildmat.2018.04.017","article-title":"3DP of earth-based materials: Processing aspects","volume":"172","author":"Perrot","year":"2018","journal-title":"Constr. Build. Mater."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"105545","DOI":"10.1016\/j.autcon.2024.105545","article-title":"Contribution of production processes in environmental impact of low carbon materials made by additive manufacturing","volume":"165","author":"Chadha","year":"2024","journal-title":"Autom. Constr."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"135714","DOI":"10.1016\/j.conbuildmat.2024.135714","article-title":"3DP earth: Local, circular material processing, fabrication methods, and life cycle assessment","volume":"421","author":"Curth","year":"2024","journal-title":"Constr. Build. Mater."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"100284","DOI":"10.1016\/j.dibe.2023.100284","article-title":"Advancements in low-carbon concrete as a construction material for the sustainable built environment","volume":"16","author":"Althoey","year":"2023","journal-title":"Dev. Built Environ."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1221","DOI":"10.1617\/s11527-012-9828-z","article-title":"Mix design and fresh properties for high-performance printing concrete","volume":"45","author":"Le","year":"2012","journal-title":"Mater. Struct."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1675","DOI":"10.5194\/essd-11-1675-2019","article-title":"Global CO2 emissions from cement production, 1928\u20132018","volume":"11","author":"Andrew","year":"2019","journal-title":"Earth Syst. Sci. Data"},{"key":"ref_19","unstructured":"Moquin, M. (1994, January 6\u20139). Ancient Solutions for Future Sustainability: Building with Adobe, Rammed Earth, and Mud. Proceedings of the CIB TG 16 Sustainable Construction Conference, Tampa, FL, USA. Available online: https:\/\/www.irbnet.de\/daten\/iconda\/CIB_DC24848.pdf."},{"key":"ref_20","first-page":"448","article-title":"Sustainable building materials utilization in the construction sector and the implications on labour productivity","volume":"24","author":"Adebowale","year":"2023","journal-title":"J. Eng. Des. Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"595","DOI":"10.1080\/09613210701467040","article-title":"The next generation of sustainable construction","volume":"35","author":"Kibert","year":"2007","journal-title":"Build. Res. Inf."},{"key":"ref_22","unstructured":"New Mexico Regulation and Licensing Department (2026, March 18). 2021 New Mexico Earthen Building Materials Code; Title 14, Chapter 7, Available online: https:\/\/www.srca.nm.gov\/parts\/title14\/14.007.0004.html."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Smith, E.W., and Austin, G.S. (1989). Adobe, Pressed-Earth, and Rammed-Earth Industries in New Mexico, New Mexico Bureau of Mines and Mineral Resources.","DOI":"10.58799\/B-127"},{"key":"ref_24","unstructured":"Cornerstones Community Partnership (2006). Adobe Conservation: A Preservation Handbook, Sunstone Press. Available online: https:\/\/www.cstones.org."},{"key":"ref_25","unstructured":"Bhusal, S. (2021). 3DP of Earthen Materials: Toward Carbon-Zero Construction. [Master\u2019s Thesis, The University of New Mexico]. Available online: https:\/\/digitalrepository.unm.edu\/ce_etds\/294\/."},{"key":"ref_26","unstructured":"Bhusal, S., Uvi\u00f1a Contreras, F., and Hojati, M. (2022). Preliminary Study on 3D Printing of Locally Available Earthen Materials in New Mexico, The University of New Mexico. Available online: https:\/\/www.researchgate.net\/publication\/365945674_PRELIMINARY_STUDY_ON_3D_PRINTING_OF_LOCALLY_AVAILABLE_EARTHEN_MATERIALS_IN_NEW_MEXICO."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Bhusal, S., Sedghi, R., and Hojati, M. (2023). Evaluating the printability and rheological and mechanical properties of 3D-printed earthen mixes for carbon-neutral buildings. Sustainability, 15.","DOI":"10.3390\/su152115617"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1108\/17506200710833827","article-title":"Taos Pueblo: An indigenous community holding on to Promethean values","volume":"1","author":"Dana","year":"2007","journal-title":"J. Enterprising Communities"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Smith, E.W. (1982). Adobe Bricks in New Mexico, New Mexico Bureau of Mines and Mineral Resources.","DOI":"10.58799\/C-188"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"114588","DOI":"10.1016\/j.geoderma.2020.114588","article-title":"3DP: An emerging opportunity for soil science","volume":"378","author":"Derrien","year":"2020","journal-title":"Geoderma"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Daher, J., Kleib, J., Benzerzour, M., Abriak, N.-E., and Aouad, G. (2023). The development of soil-based 3D-printable mixtures: A mix-design methodology and a case study. Buildings, 13.","DOI":"10.3390\/buildings13071618"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1016\/j.procir.2023.08.035","article-title":"Sustainability of 3DP in infrastructure development","volume":"120","author":"Wilson","year":"2023","journal-title":"Procedia CIRP"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"136569","DOI":"10.1016\/j.jclepro.2023.136569","article-title":"Automation in rammed earth construction for industry 4.0: Precedent work, current progress and future prospect","volume":"398","author":"Gomaa","year":"2023","journal-title":"J. Clean. Prod."},{"key":"ref_34","unstructured":"Rael San Fratello (2026, March 18). Rael San Fratello 3D Prints Mud Structures as Prototypes for Low-Cost Construction. Dezeen, Available online: https:\/\/www.dezeen.com\/2019\/10\/03\/mud-frontiers-rael-san-fratello-3d-printed-low-cost-construction\/."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"106097","DOI":"10.1016\/j.cemconres.2020.106097","article-title":"Innovating materials for large-scale additive manufacturing: Salt, soil, cement and chardonnay","volume":"134","author":"Fratello","year":"2020","journal-title":"Cem. Concr. Res."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"124079","DOI":"10.1016\/j.conbuildmat.2021.124079","article-title":"Feasibility of 3DP cob walls under compression loads in low-rise construction","volume":"301","author":"Gomaa","year":"2021","journal-title":"Constr. Build. Mater."},{"key":"ref_37","unstructured":"Scoggins, H. (1981). The Portalab Manual: Low-Cost Soil-Engineering Tests for Construction of Earthen Buildings, New Mexico Appropriate Technology Program. Available online: https:\/\/www.scribd.com\/document\/349121664\/The-Portalab-Manual."},{"key":"ref_38","unstructured":"Wolfskill, L., Dunlap, W., and Gallaway, B. (2026, March 18). Handbook for Building Homes of Earth, Available online: https:\/\/files.eric.ed.gov\/fulltext\/ED242877.pdf."},{"key":"ref_39","unstructured":"Zozaya, D., Bhusal, S., Uvi\u00f1a Contreras, F., and Hojati, M. (2024, January 13\u201315). Evaluating grain size distribution of local soils for 3DP in construction. Proceedings of the Earth USA 2024, Santa Fe, NM, USA."},{"key":"ref_40","unstructured":"Soil Survey Staff (1993). USDA Soil Textural Classification Chart."},{"key":"ref_41","unstructured":"(2007). Standard Specification for Concrete Aggregates (Standard No. ASTM C33). Available online: https:\/\/www.astm.org\/c0033-07.html."},{"key":"ref_42","unstructured":"(2014). Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates (Standard No. ASTM C136\/C136M-14)."},{"key":"ref_43","unstructured":"(2000). Standard Practice for Classification of Soils for Engineering Purposes (USCS) (Standard No. ASTM D2487)."},{"key":"ref_44","unstructured":"(2023). Standard Test Method for Materials Finer than 75-\u03bcm (No. 200) Sieve in Mineral Aggregates by Washing (Standard No. ASTM C117-23). Available online: https:\/\/www.astm.org\/c0117-23.html."},{"key":"ref_45","unstructured":"Doat, P., Norton, C., Hays, A., Houben, H., Matuk, S., and Vitoux, F. (1991). Building with Earth, Mud Village Society. Available online: https:\/\/ia600600.us.archive.org\/13\/items\/Building_with_Earth\/Building_with_Earth.pdf?utm_source=chatgpt.com."},{"key":"ref_46","unstructured":"Dominguez, T. (2011). ABCs of Making Adobe Bricks, New Mexico State University. Available online: https:\/\/pubs.nmsu.edu\/_g\/G521\/index.html."},{"key":"ref_47","unstructured":"(2010). Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils (Standard No. ASTM D4318). Available online: https:\/\/www.astm.org\/d4318-17e01.html."},{"key":"ref_48","unstructured":"Brady, N.C., and Weil, R.R. (2007). The Nature and Properties of Soils, Pearson Prentice Hall."},{"key":"ref_49","unstructured":"VTSYIQI (2024, May 31). Digital Fruit Penetrometer Hardness Tester (0.2\u201315 kgf\/cm2, Diameter 11.1 mm). Available online: https:\/\/www.vtsyiqi.net\/products\/vtsyiqi-digital-fruit-penetrometer-hardness-tester-fruit-firmness-tester-sclerometer-with-range-0-2-to-15-kgf-cm2-diameter-11-1mm."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Glushankova, I., Ketov, A., Krasnovskikh, M., Rudakova, L., and Vaisman, I. (2018). Rice hulls as a renewable complex material resource. Resources, 7.","DOI":"10.3390\/resources7020031"},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Luh, B.S. (1991). Rice hulls. Rice: Volume I. Production\/Volume II. Utilization, Springer.","DOI":"10.1007\/978-1-4899-3754-4"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"108959","DOI":"10.1016\/j.jobe.2024.108959","article-title":"Investigation of cob construction: Review of mix designs, structural characteristics, and hygrothermal behaviour","volume":"87","author":"Haddad","year":"2024","journal-title":"J. Build. Eng."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"103577","DOI":"10.1016\/j.autcon.2021.103577","article-title":"3DP system for earth-based construction: Case study of cob","volume":"124","author":"Gomaa","year":"2021","journal-title":"Autom. Constr."},{"key":"ref_54","unstructured":"(2020). Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Standard No. ASTM C109\/C109M-02). Available online: https:\/\/store.astm.org\/c0109_c0109m-21.html."},{"key":"ref_55","unstructured":"(2017). Standard Practice for Use of Apparatus for the Determination of Length Change of Hardened Cement Paste, Mortar, and Concrete (Standard No. ASTM C490\/C490M-17). Available online: https:\/\/www.wje.com\/expertise\/laboratories\/testing-standards\/astm-c490."},{"key":"ref_56","doi-asserted-by":"crossref","unstructured":"Sedghi, R., Zafar, M.S., and Hojati, M. (2023). Exploring fresh and hardened properties of sustainable 3D-printed lightweight cementitious mixtures. Sustainability, 15.","DOI":"10.3390\/su151914425"},{"key":"ref_57","unstructured":"(2010). Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Center-Point Loading) (Standard No. ASTM C293). Available online: https:\/\/www.astm.org\/c0293-08.html."},{"key":"ref_58","doi-asserted-by":"crossref","unstructured":"Friedman-Gerlicz, C., Gelosi, D., Bell, F., and Buechley, L. (2024). WeaveSlicer: Expanding the range of printable geometries in clay. Proceedings of the CHI Conference on Human Factors in Computing Systems, ACM.","DOI":"10.1145\/3613904.3642622"},{"key":"ref_59","unstructured":"Rhinoceros, 3D. (2026, March 18). Rhinoceros 3D, Available online: https:\/\/www.rhino3d.com\/."}],"container-title":["Buildings"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-5309\/16\/6\/1261\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T05:45:06Z","timestamp":1774417506000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-5309\/16\/6\/1261"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,23]]},"references-count":59,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026,3]]}},"alternative-id":["buildings16061261"],"URL":"https:\/\/doi.org\/10.3390\/buildings16061261","relation":{},"ISSN":["2075-5309"],"issn-type":[{"value":"2075-5309","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,23]]}}}