Experimental study on fracture mechanical properties of 3D printed carbon-fiber-reinforced concrete
In order to study the fracture mechanical behavior of the printed carbon-fiber-reinforced concrete,the splitting and three-point-bending tests were conducted.The effects of the printing method and fiber content on the fracture damage mechanism,fracture mechanical properties,and microscopic crack characteristics of the specimens were analyzed.The mechanism of the anisotropy origination was explained by the comparisons of the sectional material integrity.A fitting expression between the mechanical indicators of 3D printed carbon-fiber-reinforced concrete and conventionally cast concrete was proposed.The study results indicate that:compared to the cast concrete,the printed carbon-fiber-reinforced concrete has the similar fracture process which includes the elastic stage,cracking stable expansion stage and cracking unstable expansion stage;the printing method could lead to the different weakening of the sectional material integrity and the corresponding decrease of the mechanical indicators of different material direction,respectively;if the sectional material integrity is weakened more seriously,the proportion of shear micro-cracks will increase and the enhancement of fiber bridging action will decrease with the increasing of the fiber content;due to the random of the distribution of the fiber,the reduction factors of the mechanical indicators and the amount ratio of the shear cracks have the nonlinear relationships.
3D printed carbon-fiber-reinforced concreteanisotropyfracturestatic testmaterial integritymicro-cracking
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