Influence of Type of Fibers on Fresh and Hardened Properties of Three-Dimensional-Printed Cementitious Mortars (2023-11)¶

Reinforcing strategies for three-dimensional printing (3DP) of cementitious materials (mostly mortars) have been extensively studied in recent years. Among various reinforcement strategies available for 3DP cementitious materials, the use of fibers is frequently mentioned as a promising approach to enhance their mechanical performance. This work aims to evaluate the influence of four types of fibers (PVA, nylon, rayon, and basalt) on the flowability and flexural strength of mortars used in 3DP. The flexural behavior of 3DP beams was compared with that of cast specimens, and the digital image correlation (DIC) technique was used to evaluate the development of the cracks. The fiber orientation in the reference (cast) and 3DP samples was examined using optical microscopy. The results revealed that, among the four types of fibers used, the PVA fibers were most effective in increasing the flexural strength of both the cast and 3D printed specimens. In addition, the results show that all fibers preferentially aligned parallel to the printing direction. 3DP specimens with filaments aligned in the direction perpendicular to the direction of the applied load showed superior flexural strength when compared to the cast specimens.