Bending performance of 3D printed ultra high-performance concrete composite beams

Abstract

The integrated optimization of materials, processes, and structural performance is the development trend for 3D concrete printing. Composite beam reinforced by 3D printed ultra high-performance concrete (3DP-UHPC) was proposed, i.e., 3DP-UHPC was applied as the strengthen skeleton for the entire composite beam. In this study, three 3DP-UHPC skeleton optimized forms were derived through topology optimization design. Four-point bending tests were conducted on 3DP-UHPC skeleton composite reinforced concrete beams (CRC), rebars locally reinforced CRC beams (R-CRC), and rebars locally reinforced 3D printed concrete beams (R-PC). Additionally, conventionally reinforced concrete beam (RC) was produced for comparison. The results showed that the of CRC and R-PC perform 1/4 and 1/2 flexural capacity of RC, respectively. Their limited flexural capacity led to sudden failures, failing to meet structural load requirements. In contrast, R-CRC exhibited superior stiffness and strength, demonstrating exceptional bending performance for 3D printed concrete beams without the reinforcement of reinforcement cages. This approach significantly enhances the structural load capacity of 3D printed structures while preserving flexibility and reducing reliance on reinforcement cages. The study provides valuable experimental data and methodological guidance for the application of 3D printed concrete structures in structural load-bearing engineering.