New Reinforcement Approach for Freeform Concrete Components Through Carbon Fiber 3D Printing (2024-08)¶

Concrete forming techniques have evolved to enhance resource efficiency and reduce dependence on traditional formwork. In contemporary architecture, freeform components have gained significance, facilitated by innovations in 3D printing (3DP), which allow for geometrically complex formworks. Despite the advancements, reinforcing geometrically complex concrete structures remains a significant challenge. This paper introduces a novel carbon fiber reinforcement method to effectively address the challenge of reinforcing geometrically complex concrete structures. The core of this approach lies in replacing traditional steel reinforcement methods with carbon fiber, implemented through digital fabrication. This research explores the application of 3DP to fabricate both carbon fiber reinforcements and precise formworks, aiming to create unprecedented structures with enhanced tensile properties. By positioning carbon fiber reinforcement on the exterior surface of concrete, where tensile stresses are most pronounced, the approach draws inspiration from conventional retrofitting processes, demonstrating enhanced structural efficiency compared to traditional methods. The proposed approach involves incorporating precisely engineered carbon fiber trajectories into pre-printed plastic formwork. After concrete curing, this method preserves carbon fiber trajectories upon formwork removal. A developed computational design strategy ensures the judicious application of carbon fiber only where structurally necessary. The research encompasses a series of experiments, including evaluations of fabrication strategies and 3-point shear-bending tests. These experiments indicate the capability of the proposed approach and the strong influence of carbon fibers on enhancing the shear and bending capacities of the elements. By integrating 3DP technologies and computational design methods, this research advances the approach for concrete reinforcement with improved material utilization in the fabrication of freeform concrete components. A fabricated demonstrator serves as a proof of concept for the practical application of this approach.