Evaluation and Correlation Study on Work Performance of 3D-Printed Concrete

The study aims to solve the problem that the concrete suitable for three-dimensional (3D) printing achieves more working performances, while the mutual influence, crossover, and contradiction among the working performances. In this study, a multi-index evaluated, gradual-optimized test based working performance is proposed. First, the concrete proportions satisfying 3D printing were obtained through orthogonal test and then gradually optimized systematically to the proportions determined by conducting an orthogonal experiment. The correlation between assessment indexes was analyzed. The test results show that fluidity and thixotropic sensitivity can be combined to evaluate comprehensively the work performance of 3D-printed concrete. The flow rate can further optimize the mix ratio, and the correlation between stacking height and number of extruded layers is weak. Moreover, the building performance of 3D-printed concrete can be evaluated from the number of layer and deformation of concrete to optimize the concrete ratio further. The suitable fluid range for 3D-printed concrete is 17.7-20.0 cm, and the corresponding stacking height is 45-57 mm. The successfully printed building components from the optimized concrete proportion further verify that the test method used in this study is reasonable and scientific, and that it can be extended to prepare other concretes satisfying more performance.