The relationship between the rheological behavior and interlayer bonding properties of 3D printing cementitious materials with the addition of attapulgite

The rheological behavior of fresh 3D printing concrete (3DPC) not only determines the pumpability, extrudability and buildability, but also strongly affects the interlayer properties. Which is one of the most important characteristics of 3D printing construction that shaped layer by layer. This paper systematically studied the relationship between the rheological behavior (tuned by attapulgite) and the interlayer bonding properties of 3DPC. The results showed that the interlayer bonding strength and interlayer durability strongly depend on the rheological parameters (i.e., dynamic yield stress, plastic viscosity, static yield stress and structural build-up rate). With the increase of dynamic yield stress and structural build-up rate, the interlayer bonding strength and interlayer durability both decreased. Moreover, an empirical formula combining interlayer bonding strength with the dynamic yield stress and the structural build-up rate of 3DPC, considering the porosity and hydration degree, was proposed for the first time.