Some experimental results of 3D printing concrete

Abstract

This paper presents some experimental results on the mix proportions and properties of a 3D printing concrete using available raw materials in Vietnam that comprise river sand (Dmax = 5 mm), cement, silica fume, fly ash, chemical admixture, and water. The experimental outcomes confirm that a type of 3D printing conrete can be produced and it has flowability in the range of 150 to 200 mm, workability of 1 hour, 28-day compressive strength in the range of 50 to 70 MPa. The fresh 3D printing concrete gained an reasonable extrudability speed of 100 to 400 mm per minute with the speed of nozzle of 40 mm per second and the nozzle diameter of 20 mm. The 3D printing concrete mix with a water to binder ratio of 0.35 and a sand to binder ratio of 0.67 had the best buildability in this experimental research.