Study on anisotropy of 3D printing PVA fiber reinforced concrete using destructive and non-destructive testing methods

Abstract

To further understand the mechanical properties and anisotropy characteristics of 3D printing PVA fiber reinforced concrete (PFRC). This study first obtained 3D printing PFRC mixes with superior mechanical properties through slump tests, penetration resistance tests, printability tests, and flexural tests. Second, the fiber reinforcement mechanisms and anisotropy characteristics of PFRC were analyzed by nondestructive ultrasonic pulse velocity tests, destructive mechanical property tests, and scanning electron microscope tests. Third, the correlation between mechanical properties and ultrasonic signals was analyzed, and the conversion criteria were further established. Moreover, the application range of conversion criteria was also determined. The test results showed that the optimum dosage of PVA fibers is 0.5 wt% for 3D printing FRPC, and the highest cube compressive strength and flexural strength are 98.2 MPa and 6.8 MPa, respectively. The mechanical properties and acoustics of 3D printed specimens showed significant anisotropy. The conversion criteria show a good agreement with the test data and are applicable to 3D printing fiber concrete with a small aggregate size.

Keywords

• 3D printing
• PFRC
• Anisotropy
• Ultrasonic pulse velocity
• Mechanical properties