Variation of the Adhesion Between Concrete Printed Layers in a 3D Concrete Printed Structure

3D printing is an advanced technology that is being researched and applied in the construction sector. 3D concrete printing is a technique of generating concrete structures by applying each layer of printing concrete through the control of a robot, hence reducing the amount of human participation in the production process. The adhesion between adjacent layers is one of the indicators used to assess the quality of 3D-printed concrete. Nonetheless, adhesion between printing layers frequently varies with the height of the printed concrete structures. Experiments were conducted on 3D-printed concrete square blocks with a 500mm height and 500mm length. Each layer had a thickness of 10 mm and a width of 20 mm, using the concrete mixture with a water-to-binder ratio of 0.32. The adhesion strength between printed layers was measured using a splitting tensile test according to TCVN 8862:2011 on 28-day 3D-printed concrete samples. According to experimental findings, the bonding between the layers of 3D-printed concrete reduces as the height of the printed concrete block increases.