The effect of spontaneous permeation on the interlayer bond strength of 3D printed cement mortars

The spontaneous permeation of overlay is a critical factor affecting the mechanical link of layer-to-layer interfaces. This work mainly studies the possibility of improving the interlayer bonding of 3D printed structures by increasing the spontaneous permeation of overlay. A polycarboxylate superplasticizer with high slump retention (TSRS) are employed to control the spontaneous permeation of cement-based materials. The rheological properties, micro-structure and interlayer bonding strength of printed structures with TSRS polymers are analyzed. Results indicate that fluidity is the key factor affecting the spontaneous permeation of cement-based materials. Properly improving the fluidity retention of cement-based materials can promote the spontaneous permeation of overlay, which fills part of the air-void systems of layer-to-layer interfaces, increases the mechanical interlocking and interlayer bonding strength of printed structures.