Multi-Scale Additive Manufacturing of Ultra High Performance Fiber Reinforced Concrete: Experiments and Computations

Additive Manufacturing (AM) allows for the design and manufacturing of complex shapes that liberate the imagination of designers. This opens unexplored possibilities for the performance optimization of structures and to achieve stronger, tougher, more durable, more aesthetically appealing, and more environmentally friendly products, while possibly even reducing costs. While AM is already a reality in many industry sectors, its adoption in civil engineering and construction lags behind. This is because (a) most work has been performed with cement paste or fi�ne mortar, as opposed to concrete or fi�ber-reinforced concrete; (b) controlling concrete rheology during the printing process and concrete transition from fluid to solid (setting) is problematic at best; (c) available concrete AM technologies do not allow for the use of reinforcement; and (d) analytical and computational methods for the analysis and design of printed structures do not exist. To address the aforementioned issues we propose the transformative concept of Ultra High Performance Concrete Laminate (UHPCL) which will be obtained by the AM of layers of nano-modi�ed UHPC with embedded reinforcement. The specific technical objectives of the proposed research e�ort are as follows: (1) To engineer an optimized UHPC with tailored rheology at the fresh state. (2) To elucidate the Structure-Property-Performance relationship of the formulated UHPC during printing and beyond. (3) To study the mechanical behavior of printed UHPC layers and laminas. (4) To formulate and validate a multiscale computational framework for the prediction of UHPCL behavior. (5) To demonstrate the performance of UHPCL via numerical simulations and large- scale additive manufacturing. These objectives will be achieved with an integrated experimental and computational research program comprised of 3 coordinated research thrusts, which target various length and time scales of UHPCL behavior.