{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T11:09:17Z","timestamp":1773745757614,"version":"3.50.1"},"reference-count":40,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T00:00:00Z","timestamp":1773705600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004585","name":"Ministry of Education, Youth and Sports","doi-asserted-by":"publisher","award":["FAST-S-26-8986"],"award-info":[{"award-number":["FAST-S-26-8986"]}],"id":[{"id":"10.13039\/501100004585","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>Three-dimensional (3D) printing, also known as additive manufacturing of cementitious materials, appears to be a promising way to build in a way that is more time-efficient, cost-effective and, under certain conditions, environmentally friendly. This technology continues to exhibit significant inhomogeneity, which is frequently caused by the interlayer area. The presented research aims to clarify the influence of the interlayer surface area and delay time on the bond strength. This study involved reference cast and printed samples with different delay times and cast samples with different interlayer surface areas. Different interlayer surface areas were accomplished through the utilisation of a teeth shaper before casting the second layer. Research has shown that the interlayer surface area has a significant impact on layer bond strength; up to a 70% increase in bond strength can be achieved while increasing the area by 20%. The results show that the increase in strength due to a larger surface area remained constant in terms of percentage, across delay times, with a linear dependency on a specific range of conditions. After the threshold of the surface area increased, the bond strength could be compromised and lowered. This threshold is above a 120% increase in surface area for the used teeth geometry and material. The proposed technology of ejecting teeth to alter the interlayer surface area has the potential to reduce the heterogeneity of mechanical properties in 3D-printed objects, caused by the different delay time between layers, because of the print strategy or material shortage.<\/jats:p>","DOI":"10.3390\/ma19061168","type":"journal-article","created":{"date-parts":[[2026,3,17]],"date-time":"2026-03-17T10:21:41Z","timestamp":1773742901000},"page":"1168","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Layer Bond Strength in 3D-Printed Concrete: The Role of Interlayer Surface Area and Printing Delay Time"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1857-8081","authenticated-orcid":false,"given":"Nikol","family":"\u017di\u017ekov\u00e1","sequence":"first","affiliation":[{"name":"Faculty of Civil Engineering, Institute of Technology of Building Materials and Components, Brno University of Technology, Veve\u0159\u00ed 331\/95, 602 00 Brno, Czech Republic"}]},{"given":"Josef","family":"V\u00e1lek","sequence":"additional","affiliation":[{"name":"Faculty of Civil Engineering, Institute of Technology of Building Materials and Components, Brno University of Technology, Veve\u0159\u00ed 331\/95, 602 00 Brno, Czech Republic"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8415-4346","authenticated-orcid":false,"given":"Arno\u0161t","family":"Vespalec","sequence":"additional","affiliation":[{"name":"Faculty of Civil Engineering, Brno University of Technology, Veve\u0159\u00ed 331\/95, 602 00 Brno, Czech Republic"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3686-3356","authenticated-orcid":false,"given":"Jind\u0159ich","family":"Melichar","sequence":"additional","affiliation":[{"name":"Faculty of Civil Engineering, Institute of Technology of Building Materials and Components, Brno University of Technology, Veve\u0159\u00ed 331\/95, 602 00 Brno, Czech Republic"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8021-943X","authenticated-orcid":false,"given":"S\u0142awomir","family":"Czarnecki","sequence":"additional","affiliation":[{"name":"Faculty of Civil Engineering, Wroclaw University of Science and Technology, Wybrze\u017ce Wyspia\u0144skiego 27, 50-372 Wroc\u0142aw, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5329-9534","authenticated-orcid":false,"given":"Adrian","family":"Chajec","sequence":"additional","affiliation":[{"name":"Faculty of Civil Engineering, Wroclaw University of Science and Technology, Wybrze\u017ce Wyspia\u0144skiego 27, 50-372 Wroc\u0142aw, Poland"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"105533","DOI":"10.1016\/j.compositesa.2019.105533","article-title":"A review of the current progress and application of 3D printed concrete","volume":"125","author":"Zhang","year":"2019","journal-title":"Compos. 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