协同连续布筋增韧喷射3D打印混凝土的抗弯性能

Flexural Performance of Spray-based 3D Printed Concrete with Continuous Micro-cable

喷射3D打印喷口与受喷面的间距空间可解决3D打印和钢筋协同建造的问题。本工作基于协同连续布筋和喷射3D打印混凝土工艺,提出喷射3D打印微筋混凝土的设计方法,研究了不同微筋直径(0.6、0.8、1.0 mm)和根数(1—4)对喷射3D打印微筋混凝土抗弯性能的影响规律。试验结果表明,微筋可显著提升打印混凝土的抗弯强度和韧性,对比未增强组(D0试样),喷射3D打印微筋混凝土的抗弯强度和弯曲位移分别最高提升了800%和2 076.47%。此外,基于喷射3D打印的高速喷压和逐层打印特性,微筋与喷射混凝土界面粘结密实,进一步保证了喷射3D打印微筋混凝土的抗弯性能和结构整体性。本工作打印了尺寸为1 300 mm (Z)×800 mm (X)×86 mm (Y)的异形火炬结构,验证了喷射3D打印微筋混凝土系统的实用性,为3D打印钢筋混凝土结构的制备及在大尺寸结构中的应用提供了一定的参考。

The distance between the spray nozzle and the print substrate can effectively solve the co-construction problem of 3D printing and reinforcement.In this work,a design method of spray-based 3D printed micro-cable reinforced concrete was proposed based on the collaborative continuous reinforcement and sprayed-based 3D printing concrete technologies.The effects of different reinforcement diameter(0.6,0.8,1.0 mm)and number(1-4)on the flexural performance of spray-based 3D printed micro-cable reinforced concrete were comprehensively studied.The test results show that the micro-cable can significantly improve the flexural strength and ductility of the printed concrete.Compared with the unreinforced group(D0 sample),the flexural strength and displacement of the printed micro-cable reinforced concrete are enhanced by 800%and 2076.47%,respectively.In addition,based on the high-speed spraying pressure and layer-by-layer printing characteristics of spray-based 3D printing,the interface between the micro-cable and concrete is bonded firmly and compactly,which further ensures the flexural performance and structural integrity of spray-based 3D printed micro-cable concrete.To verify the practicability of the spray-based 3D printed micro-cable reinforced concrete system,a special-shaped torch structure with the size of 1300 mm(Z)×800 mm(X)×86 mm(Y)is printed,which provides a certain reference for the preparation and application of 3D printed reinforced concrete structures in large scale.