Yu Ke-Ke, Zhao Tai-Qi, Luo Qi-Ling, Ping Yang
State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, China.
Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, China.
Materials (Basel). 2024 Oct 21;17(20):5126. doi: 10.3390/ma17205126.
Three-dimensional printed concrete (3DPC) is increasingly recognized in the construction industry for its high design flexibility and the elimination of conventional formwork. However, weak interlayer adhesion remains a significant challenge. The potential of recycled polyethylene terephthalate (PET) fibers for reinforcing 3DPC is being explored, driven by their environmental sustainability and economic advantages. However, there is an inadequate interfacial adhesion between these recycled fibers and the 3DPC matrix. This study investigated the use of dopamine modification to address this issue and enhance the interlayer adhesion of fiber-reinforced 3DPC. Recycled PET fibers were surface-modified using dopamine treatment, forming a polydopamine (PDA) film that improved surface roughness and hydrophilicity. Both unmodified and modified fibers were incorporated into 3DPC at various volume fractions (0.1%, 0.3%, 0.5%). The effects on interlayer adhesion strength, compressive strength, and flexural strength were systematically evaluated and compared. The results showed that the inclusion of 0.3 vol% dopamine-modified fibers resulted in a 22.5% increase in interlayer adhesion strength compared to the control group, and a 14.8% improvement over unmodified fibers at the same content. Additionally, the compressive strength and flexural strength of 3DPC with 0.3 vol% MPET fibers increased by 22.5% and 27.6%, respectively, compared to the control group. Microstructural analysis using SEM and XRD revealed that the dopamine modification significantly improved the interfacial adhesion between fibers and the concrete matrix, explaining the superior performance of modified fibers. This study demonstrates that recycled PET fibers modified with dopamine can effectively enhance the interlayer adhesion of 3DPC. The findings affirm that surface modification techniques can significantly elevate the utility of recycled PET fibers in 3DPC, contributing to the sustainable advancement of construction materials.
三维打印混凝土（3DPC）因其高度的设计灵活性和无需传统模板而在建筑行业中越来越受到认可。然而，层间粘结薄弱仍然是一个重大挑战。鉴于其环境可持续性和经济优势，人们正在探索回收聚对苯二甲酸乙二酯（PET）纤维增强3DPC的潜力。然而，这些回收纤维与3DPC基体之间的界面粘结不足。本研究调查了使用多巴胺改性来解决这一问题并增强纤维增强3DPC的层间粘结。通过多巴胺处理对回收PET纤维进行表面改性，形成聚多巴胺（PDA）薄膜，改善了表面粗糙度和亲水性。将未改性和改性纤维以不同的体积分数（0.1%、0.3%、0.5%）掺入3DPC中。系统评估并比较了其对层间粘结强度、抗压强度和抗弯强度的影响。结果表明，与对照组相比，掺入0.3 vol%多巴胺改性纤维可使层间粘结强度提高22.5%，在相同含量下比未改性纤维提高14.8%。此外，与对照组相比，含有0.3 vol%改性PET纤维的3DPC的抗压强度和抗弯强度分别提高了22.5%和27.6%。使用扫描电子显微镜（SEM）和X射线衍射（XRD）进行的微观结构分析表明，多巴胺改性显著改善了纤维与混凝土基体之间的界面粘结，这解释了改性纤维的优异性能。本研究表明，用多巴胺改性的回收PET纤维可以有效地增强3DPC的层间粘结。研究结果证实，表面改性技术可以显著提高回收PET纤维在3DPC中的效用，有助于建筑材料的可持续发展。
