Development of a 3D-Printable Ultra-High Performance Fiber-Reinforced Concrete for Digital Construction

Abstract

This paper presents the systematic development and performance characterization of a nonproprietary 3D-printable ultra-high-performance fiber-reinforced concrete (UHPFRC) for digital construction. Several fresh and hardened properties of the developed 3D-printable UHPFRC matrix (without fiber) and composite (with 2% volume fraction of steel fibers) were evaluated and compared to that of conventionally mold-cast UHPFRC. Additionally, the effects of testing direction on the compressive and flexural strengths of the printed UHPFRC were investigated.The fresh properties of the UHPFRC developed in this study satisfied the criteria for extrudability, buildability, and shape-retention-ability, which are relevant for ensuring printability. The printed UHPFRC exhibited superior flexural performance to the mold-cast UHPFRC due to alignment of the short fibers in the printing direction. The high compressive and flexural strengths, along with the deflection-hardening behavior, of the developed UHPFRC can enable the production of thin 3D-printed components with significant reduction or complete elimination of conventional steel bars.

An overview of recent advancements in fibre-reinforced 3D printing concrete

“…It has been established that when the average length of reinforcing fibres exceeds the diameter of the nozzle, they line up along the direction of movement through the nozzle, as depicted in Figure 2, as presented by Zhang et al (2021). Research has shown that aligning the fibres in parallel with the printing direction improves printed samples' bending resistance compared to traditionally cast counterparts (Arunothayan et al, 2020;Ziaee et al, 2022;Zhou et al, 2023). This effect can be explained by the fact that the maximum bridging effect will take place when fibres are oriented perpendicular to the crack.…”

“…The study examined how the testing direction affected the compressive strength and rupture modulus of 3D-printed ultra-high-performance fibrereinforced concrete. Furthermore, it investigated the relationship between fibre orientation and the mechanical properties of the printed samples (Arunothayan et al, 2020;Arunothayan et al, 2021). Given the increasing need for higher safety standards in civil engineering worldwide, it has become essential to comprehend the dynamic mechanical properties.…”

“…Other studies have used similar methodologies to evaluate extrudability (Le et al, 2012a;Bong et al, 2019). It is worth mentioning that prior research has used a comparable technique to examine the ability of fresh printing materials to retain their shape (Nematollahi et al, 2018a;Arunothayan et al, 2020). A pictorial depiction for buildability of 3D specimens is shown in Figure 9, as presented by Robayo-Salazar et al (2023).…”