Maroszek Marcin, Rudziewicz Magdalena, Rusin-Żurek Karina, Hager Izabela, Hebda Marek
Department of Materials Engineering, Faculty of Materials Engineering and Physics, Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland.
Chair of Building Materials Engineering, Faculty of Civil Engineering, Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland.
Materials (Basel). 2025 Sep 19;18(18):4387. doi: 10.3390/ma18184387.
Three-dimensional concrete printing (3DCP) is advancing rapidly, yet its sustainable adoption requires alignment with circular-economy principles. This study evaluates the substitution of natural aggregates with recycled constituents, 3DCP waste, brick debris, glass cullet, mixed rubble, fly ash, and slag, and the use of lightweight fillers (expanded perlite, lightweight expanded clay aggregate (LECA), and expanded polystyrene (EPS)) to reduce density and improve insulation. Key properties, such as particle-size distribution, printability, mechanical performance, thermal conductivity, and water absorption, were determined. Results indicate that grading strongly affected mixture behavior. Narrow distributions (fly ash, milled 3DCP waste) enhanced extrudability, while broader gradings (glass, rubble, slag) increased water demand and extrusion risks. Despite these differences, all systems remained within the printable window: flow spread decreased with most recycled additions (lowest for brick) and increased with glass. Mechanical responses were composition-dependent. Flexural strength typically decreased. Compressive strength benefited from broader gradings, with replacement levels up to ~6% enhancing strength due to improved packing. Loading anisotropy typical of 3DCP was observed, with perpendicular compressive strength reaching up to 13% higher values than parallel loading. Lightweight fillers significantly reduced thermal conductivity. LECA provided the best compromise between strength and insulation, perlite showed intermediate behavior, and EPS achieved the lowest thermal conductivity but induced significant strength penalties due to weak matrix-EPS interfaces. Water absorption decreased in recycled-aggregate mixes, whereas lightweight systems, particularly with perlite, retained higher uptake. The results demonstrate that non-reactive recycled aggregates and lightweight insulating fillers can be successfully integrated into extrusion-based 3DCP without compromising printability.
三维混凝土打印（3DCP）正在迅速发展，但其可持续应用需要符合循环经济原则。本研究评估了用再生成分、3DCP废料、砖屑、碎玻璃、混合 rubble、粉煤灰和矿渣替代天然骨料，以及使用轻质填料（膨胀珍珠岩、轻质膨胀粘土骨料（LECA）和膨胀聚苯乙烯（EPS））来降低密度和改善隔热性能。测定了关键性能，如粒度分布、可打印性、力学性能、热导率和吸水性。结果表明，级配强烈影响混合料性能。窄分布（粉煤灰、磨碎的3DCP废料）提高了挤出性，而较宽级配（玻璃碎、rubble、矿渣）增加了需水量和挤出风险。尽管存在这些差异，但所有体系仍在可打印范围内：随着大多数再生添加物的加入，流动扩展减小（砖的最小），而随着玻璃的加入，流动扩展增加。力学响应取决于成分。抗弯强度通常降低。抗压强度受益于较宽级配，由于填充改善，替代水平高达约6%时强度提高。观察到3DCP典型的加载各向异性，垂直抗压强度比平行加载时高出13%。轻质填料显著降低了热导率。LECA在强度和隔热之间提供了最佳折衷，珍珠岩表现出中等性能，而EPS实现了最低的热导率，但由于基体-EPS界面薄弱导致强度显著降低。再生骨料混合料的吸水率降低，而轻质体系，特别是含珍珠岩的体系，吸水率保持较高。结果表明，非活性再生骨料和轻质隔热填料可以成功地集成到基于挤出的3DCP中，而不影响可打印性。
