An Experimental Study on Energy Absorption Capability of Cast and 3D Printed Architected Cement-based Materials

Department of Civil Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, 113-8656, Japan

^* Corresponding author: imagawa@concrete.t.u-tokyo.ac.jp

Abstract

Previous studies have demonstrated that Architected Cement-based Materials (ACMs), which have architected internal configurations at mm-cm scale, can have desired and/or unusual mechanical characteristics that the brittle base material does not possess. 3D Concrete Printing (3DCP) is promising technology to fabricate the complicated geometry of ACMs, but relevant research and development are still scarce. In this study, we fabricated truss-type ACMs with enhanced specific energy absorption capacity by either casting or 3D-printing. The ACM was designed by a generative design framework that integrates reinforcement learning and nonlinear structural analysis. The performances of the ACMs were evaluated by uniaxial compression tests. The cast series showed same trend in the cracking characteristics as the simulation. However, the printed ACM showed significantly lower strength and energy absorption than the simulation result. Unexpected damage localization was observed in the printed ACM, especially around the corners of the truss members where relatively large voids tend to be formed during 3D-printing. The degree and location of these defects can be partly controlled by the printing path, which was not considered in the simulation. Therefore, to realize high-performance ACMs by 3DCP, base material properties, internal geometry, and printing path should be simultaneously considered in the design process.