The Influence of Polypropylene Fiber on the Working Performance and Mechanical Anisotropy of 3D Printing Concrete

Abstract

The paper aims to clarify the influence of fiber properties on the working performance and mechanical properties of 3D printing concrete (3DPC). This paper investigates the effects of polypropylene fiber content and length on the working performance and mechanical anisotropy of 3DPC. The research results show that with the increase of polypropylene fiber content, the static yield stress, and the dynamic yield stress of 3DPC increase, the extrudability decreases. The buildability first increases and then decreases. As the length of polypropylene fiber increases, the static yield stress and dynamic yield stress increase, and the extrudability decreases. The buildability first increases and then decreases. The printability of 3DPC with 9 mm length fiber is better than that with 6 mm and 12 mm. Through the compressive strength and flexural strength tests of 3DPC, it was found that both the compressive strength and flexural strength have obvious anisotropy. The addition of fiber has a positive effect on the improvement of the compressive strength in three directions, and the flexural strength in the vertical and transverse directions is improved. Through work performance and mechanical anisotropy testing, it can provide a reference for optimizing the use of fibers in 3DPC.