Mix design and 3D printing correlation performance of Pcc-based 3DPM

Abstract

This paper presents the experimental results concerning the mix design and 3D printing correlation performance of a completely new printing material, Portland cement clinker (Pcc). According to the results, the cement-sand ratio is 0.6–1.0, the water-cement ratio is 0.34–0.4, and the setting time of Pcc paste is approximately 5 min. When it increases, the rheology (G', G″, |η*|, torque) of Pcc paste also increases. Furthermore, when the cement-sand ratio and water-cement ratio increase, the maximum flexural strength and compressive strength of the mortar at 28 days are 7.93 MPa and 44.76 MPa, respectively. The ultimate swelling degree of the mortar increases from 18 cm to 22 cm, the final slump increases from 4.0 cm to 4.5 cm. When the ratio is D-2, the extrusion length is 70 mm, and the maximum number of printing layers is 17 layers. According to the SEM image analysis of the sample, the hydration products primarily include hydrated calcium silicate, calcium hydroxide, and others, which is supported by the XRD test results. In addition, the reaction model of Pcc is proposed. The results of Pcc hydration reaction analysis indicate that adding a water-lowering agent can slow the cement hydration reaction.