3D-printable quaternary cementitious materials towards sustainable development: Mixture design and mechanical properties

Abstract

Development of 3D-printing technologies for cementitious materials becomes one of the driving forces to accelerate innovation in modern construction. The use of mineral and chemical admixtures in concrete has been found to benefit fresh and hardened properties and reduce the carbon footprint of portland cement. Towards this aim, four different supplementary cementitious materials, including metakaolin, silica fume, blast furnace slag, and sodium metasilicate, were utilized in binary, ternary, and quaternary cementitious blends. Flowability, setting, and compressive strength were measured to investigate the effects of different admixtures and their combinations on materials properties of printable mixtures. Selected mixtures were 3D-printed into cylinder specimens to assess their printing quality. The optimal mixture with up to 32.5% cement replacement was 3D-printed to evaluate mechanical properties (i.e., compressive strength and elastic modulus) based on prism specimens. The anisotropic behavior under compression load was observed. 3D-printed specimens tested under perpendicular direction showed the lowest compressive strength but the highest elastic modulus.