{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,3]],"date-time":"2026-04-03T06:05:47Z","timestamp":1775196347552,"version":"3.50.1"},"reference-count":40,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T00:00:00Z","timestamp":1775001600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"crossref","award":["22408094"],"award-info":[{"award-number":["22408094"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Science and Technology Project of Henan Province","award":["252102231064"],"award-info":[{"award-number":["252102231064"]}]},{"name":"Key scientific research project of Henan University","award":["24A560027"],"award-info":[{"award-number":["24A560027"]}]},{"name":"Colleges Young Teacher Training Project of Henan Province","award":["2023GGJS074"],"award-info":[{"award-number":["2023GGJS074"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Buildings"],"abstract":"<jats:p>Building 3D printing technology exhibits remarkable construction advantages, with solid waste-based 3D printing slurry emerging as a research hotspot in the field. Phosphogypsum is compatible with diverse solid wastes for the fabrication of geopolymer, whereas its feasibility as a 3D printing material merits further investigation. In this study, calcium carbide slag (CS), ground granulated blast-furnace slag (GGBS), recycled concrete powder (RCP), and phosphogypsum (PG) underwent co-activation. The mix proportion received optimization via response surface methodology (RSM), and printability assessment proceeded based on the optimized proportion. Key conclusions include the following: PG exerts a role in optimizing the internal structure within the geopolymer matrix. The 28-day compressive strength of the composite geopolymer exceeds 25 MPa. Application as a 3D printing material facilitates enhancement of slurry stability in the later stage. Excessive PG addition elevates the shear stress and viscosity of the 3D printing paste, shortens the paste open time, and impedes paste extrusion and molding. Based on a comprehensive analysis of printability and the performance of printed specimens, the optimal mix proportion of the phosphogypsum-based geopolymer 3D printing paste was determined as follows: CS: 22.5%; GGBS: 45%; RCP: 22.5%; PG: 10%; W\/b: 0.4.<\/jats:p>","DOI":"10.3390\/buildings16071387","type":"journal-article","created":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T10:09:21Z","timestamp":1775038161000},"page":"1387","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Mix Proportion Design and Performance Regulation of 3D-Printing Phosphogypsum-Based Geopolymer Paste"],"prefix":"10.3390","volume":"16","author":[{"given":"Pengjia","family":"Zhu","sequence":"first","affiliation":[{"name":"The Fifth Engineering Co., Ltd. of China Railway Seventh Group, Zhengzhou 450016, China"}]},{"given":"Hailong","family":"Tan","sequence":"additional","affiliation":[{"name":"School of Civil Engineering and Transportation, North China University of Water Resources and Electric Power, Zhengzhou 450045, China"}]},{"given":"Juntao","family":"Ma","sequence":"additional","affiliation":[{"name":"School of Civil Engineering and Transportation, North China University of Water Resources and Electric Power, Zhengzhou 450045, China"}]},{"given":"Jianguang","family":"Yin","sequence":"additional","affiliation":[{"name":"The Fifth Engineering Co., Ltd. of China Railway Seventh Group, Zhengzhou 450016, China"}]},{"given":"Binbin","family":"Zhang","sequence":"additional","affiliation":[{"name":"The Fifth Engineering Co., Ltd. of China Railway Seventh Group, Zhengzhou 450016, China"}]},{"given":"Yuping","family":"Tong","sequence":"additional","affiliation":[{"name":"School of Materials Science and Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, China"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"106070","DOI":"10.1016\/j.cemconres.2020.106070","article-title":"3D printing of concrete: Beyond horizons","volume":"133","author":"Khan","year":"2020","journal-title":"Cem. 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