{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T06:11:43Z","timestamp":1775023903430,"version":"3.50.1"},"reference-count":36,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,3,30]],"date-time":"2026-03-30T00:00:00Z","timestamp":1774828800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Young Science and Technology Talent Project","award":["2023RC3150"],"award-info":[{"award-number":["2023RC3150"]}]},{"name":"National Key Scientific Instruments and Equipments Development Project of China","award":["52327812"],"award-info":[{"award-number":["52327812"]}]},{"name":"Major Water Conservancy Science and Technology Project of Hunan Province","award":["XSKJ2025056-12"],"award-info":[{"award-number":["XSKJ2025056-12"]}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China\n              https:\/\/ror.org\/01h0zpd94","doi-asserted-by":"publisher","award":["52009040"],"award-info":[{"award-number":["52009040"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004735","name":"Hunan Provincial Natural Science Foundation of China","doi-asserted-by":"crossref","award":["2026JJ70099"],"award-info":[{"award-number":["2026JJ70099"]}],"id":[{"id":"10.13039\/501100004735","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>Interlayer bond strength is critical for ensuring the safety and durability of 3D-printed concrete (3DPC) structures. However, there remains a lack of real-time prediction methods addressing interlayer performance under the combined effects of interval time and environmental factors during the in situ printing process. To address this issue, this study conducted experiments considering various printing interval times and environmental conditions, incorporating monitoring of dielectric constant and water evaporation, alongside interlayer splitting tensile tests. By integrating the SHAP interpretability algorithm with nonlinear regression analysis, the results indicate that the printing interval time is the dominant factor inducing interlayer strength decay (with a contribution rate of 68.6%), while relative humidity emerges as the primary environmental variable (with a contribution rate of 21.3%). Mechanism analysis reveals that prolonged printing intervals intensify the hydration of the lower deposited layer, leading to reduced interfacial moisture content and loss of plasticity. Furthermore, environmental evaporation significantly regulates this process, with high-humidity environments notably mitigating the moisture loss and strength reduction caused by time delays. Based on the correlation mechanism between moisture and strength, a dimensionless general prediction model for 3DPC interlayer strength was established, incorporating printing interval time and an evaporation index (goodness of fit, R2 = 0.96). Consequently, a digital twin quality inversion scheme based on companion specimen monitoring and printing timestamps was proposed. This study quantifies the intrinsic relationships among printing interval time, environmental conditions, and interlayer strength, offering a novel approach for determining the construction window and achieving non-destructive quality prediction for 3DPC in complex environments.<\/jats:p>","DOI":"10.3390\/ma19071377","type":"journal-article","created":{"date-parts":[[2026,3,31]],"date-time":"2026-03-31T08:09:18Z","timestamp":1774944558000},"page":"1377","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Prediction Model of Interlayer Bond Strength for 3D-Printed Concrete Considering Printing Interval and Environmental Effects"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9075-2331","authenticated-orcid":false,"given":"Wenbin","family":"Xu","sequence":"first","affiliation":[{"name":"College of Water Resources and Civil Engineering, Hunan Agricultural University, Changsha 410128, China"},{"name":"State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China"}]},{"given":"Zihao","family":"Xu","sequence":"additional","affiliation":[{"name":"College of Water Resources and Civil Engineering, Hunan Agricultural University, Changsha 410128, China"}]},{"given":"Tao","family":"Liu","sequence":"additional","affiliation":[{"name":"Hunan Port Shipping and Water Resources Group Co., Ltd., Changsha 410029, China"}]},{"given":"Jun","family":"Ouyang","sequence":"additional","affiliation":[{"name":"Hunan Port Shipping and Water Resources Group Co., Ltd., Changsha 410029, China"}]},{"given":"Juan","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China"}]},{"given":"Hailong","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1380-9103","authenticated-orcid":false,"given":"Wenqiang","family":"Xu","sequence":"additional","affiliation":[{"name":"College of Water Resources and Civil Engineering, Hunan Agricultural University, Changsha 410128, China"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/j.cemconres.2018.05.006","article-title":"3D printing using concrete extrusion: A roadmap for research","volume":"112","author":"Buswell","year":"2018","journal-title":"Cem. 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