The weak interlayer adhesion caused by the layer-by-layer 3D printing (3DP) process and the incorporation of organic fiber in Engineered Cementitious Composites (ECC), detrimentally impacts the integrity of 3DP-ECC structures, particularly for large-scale structures requiring extended open time. To optimize the printing quality and extent the operation time, cellulose filaments (CF) were employed as nano-reinforcement, viscosity modifier and water retainer, and were hybridized with polyethylene fiber (PE) and steel fiber (ST). The highest bonding strength was raised up to 3.51 MPa. The time-dependent escalation of rheological parameters was mitigated, reducing interlayer porosity to 0.56 % and limiting the reduction in bonding strength to 12.01 % within 60 min open time. The compressive anisotropy was almost eliminated, verifying the potential of CF in modifying interlayer adhesion. A linear correlation between rheological behavior and interlayer bonding performance was established, and a 0.508 Pa s/min plastic viscosity growth rate was suggested to avoid cold joint and ensure printing quality.

中文翻译：

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3D 打印工程水泥基复合材料 （ECC） 的层间粘合性能：流变调节和纤维杂化


逐层 3D 打印 （3DP） 工艺和工程水泥基复合材料 （ECC） 中有机纤维的掺入导致的层间粘附力较弱，对 3DP-ECC 结构的完整性产生不利影响，特别是对于需要延长开放时间的大型结构。为了优化打印质量和延长操作时间，采用纤维素丝 （CF） 作为纳米增强剂、粘度调节剂和水保持剂，并与聚乙烯纤维 （PE） 和钢纤维 （ST） 杂交。最高粘合强度提高到 3.51 MPa。流变参数的时间依赖性升级得到缓解，层间孔隙率降低至 0.56 %，并在 60 min 开放时间内将粘合强度降低至 12.01 %。压缩各向异性几乎被消除，验证了 CF 在改变层间粘附方面的潜力。建立了流变行为与层间粘合性能之间的线性相关性，并建议 0.508 Pa s/min 的塑料粘度增长率以避免冷接并确保打印质量。