3D打印铁尾矿砂混凝土的力学和冻融循环耐久性研究

Mechanical and Freeze-thaw Cycle Durability Study of 3D Printed Iron Tailing Sand Concrete

研究铁尾矿砂掺量(0%、15%、30%、45%),加载方向(X、Y、Z),养护龄期(3 d、14 d、28 d)对3D打印铁尾矿砂混凝土的抗压强度、劈裂抗拉强度和抗弯强度的影响。结果表明:随着铁尾矿砂掺量的增加,3D打印铁尾矿砂混凝土在X、Y、Z方向上的抗压强度均下降,当铁尾矿砂掺量为45%时,3D打印混凝土在X、Y方向上的劈裂抗拉强度较普通混凝土分别降低了17.4%、17.6%,3D打印混凝土在X、Y、Z方向上的抗弯强度较普通混凝土分别提高了25.0%、31.0%和42.4%;3D打印铁尾矿砂混凝土较3D打印普通混凝土在X、Y、Z方向上的抗压强度分别降低了11.1%、19.0%和3.3%,3D打印铁尾矿砂混凝土和3D打印普通混凝土在X方向上的劈裂抗拉强度最高,在Z方向上的抗弯强度最高;掺加铁尾矿砂有利于3D打印混凝土后期力学性能的提升;经历冻融循环100次后,3D打印铁尾矿砂混凝土在Z方向的抗压强度损失率较高,在Y方向上的抗弯强度损失率较高。

To study the effect of iron tailings sand content(0%,15%,30%,45%),loading direction(X,Y,Z)and curing age(3 d,14 d,28 d)on 3D printing iron tails Influence of compressive strength,splitting tensile strength and flexural strength of mineral sand concrete.The results show that with the increase of iron tailing sand content,the compressive strength of 3D printed iron tailings sand concrete in X,Y and Z directions decreases,the splitting tensile strength in the X and Y directions is 17.4%and 17.6%lower than that of ordinary concrete,respectively,and the flexural strength of 3D printed concrete in X,Y and Z directions is 25.0%,31.0%,and 42.4%higher than that of ordinary concrete,respectively.The compressive strength of 3D printed iron tailings sand concrete is 11.1%,19.0%and 3.3%lower than that of 3D printed ordinary concrete in X,Y and Z directions respectively.The splitting tensile strength in the X direction is the highest,and the flexural strength in the Z direction is the highest;the addition of iron tailings sand is conducive to the improvement of the mechanical properties of the 3D printed concrete in the later stage;after experiencing freeze-thaw cycles for 100 times,3D printed iron tailing sand concrete has a higher loss of compressive strength in the Z-direction and a higher loss of flexural strength in the Y-direction.