Shrinkage and Mechanical Properties Optimization of Spray-Based 3D Printed Concrete by PVA-Fiber (2022-04)¶

Spray-based 3D (S-3D) concrete printing (S-3DCP) technology shows the dexterity in horizontal, vertical and overhanging construction, which demonstrates the application of S-3DCP in sextuple space. However, the high spraying pressure, layer-by-layer printing and no form construction process in S-3DCP greatly increases the shrinkage and cracking performance, which further decreases the mechanical properties of S-3D printed concrete. In light of the feature of high tensile strength, PVA fiber is widely used to overcome these limitations. In this paper, the shrinkage and mechanical properties of S-3D printed concrete optimized by PVA fiber are comprehensively studied. The PVA fiber alignment effect avails the mechanical and the anti-shrinkage properties. PVA fiber significantly improves the anti-shrinkage property of S-3D printed concrete with the cracking index and drying shrinkage respect decreased by 73.85%-100% and 9.73%-16.22%. Furthermore, the maximum flexural strength of S-3D printed concrete is significantly improved by 72.43% than that of the cast counterpart. S-3DCP optimizes the pore structure of S-3D printed concrete with the total porosity decreased by 31.08%, which avails its mechanical performance improvement.