纳米二氧化硅对白水泥基3D打印材料结构变形、流变及力学性能的影响

Effect of Nano-Silica on Structural Deformation,Rheological and Mechanical Properties of 3D Printed White Portland Cement-Based Materials

与传统建筑材料相比,3D打印建筑材料的结构建立对打印材料的流变性能具有更高的要求。通过引入纳米二氧化硅来调控白水泥基3D打印材料的流变性能,旨在稳定打印后的浆体结构和改善材料的力学性能。研究表明,纳米二氧化硅的掺入可以明显缩短浆体的凝结时间,改善其早期力学性能。同时,纳米二氧化硅的掺入能够提高浆体的屈服应力和弹性模量,这有利于浆体抵抗自身的重力,降低打印结构变形。此外,当纳米二氧化硅掺量达到0.5%(质量分数)时,白水泥基3D打印材料的3 d抗压强度和抗折强度分别可以达到46.9 MPa和6.1 MPa。从流变参数的相关性分析可以看出,动态屈服性能对打印结构变形的影响较小,静态屈服应力对打印结构变形的影响较大。综上所述,在白水泥基3D打印材料中引入纳米二氧化硅可以很好地调控浆体的流变性能,改善3D打印结构和早期力学性能。

Compared with the traditional building materials,the printed structure build-up of 3D printed building materials proposes higher requirements on the rheological properties.The nano-silica was introduced to control the rheological properties of 3D printed white Portland cement-based materials,aiming to stabilize the paste structure and improve the mechanical properties.The experimental results show that the nano-silica shortens the setting time significantly,and improves the early mechanical properties of 3D printed white Portland cement-based materials.Meanwhile,the addition of nano-silica in 3D printed white Portland cement-based materials improves the yield stress and elastic modulus,which is conducive to resist its own gravity and reduce printed structural deformation.In addition,the 3 d compressive strength and flexural strength reach up to 46.9 MPa and 6.1 MPa,respectively,when the dosage of nano-silica reaches 0.5%(mass fraction).Based on the correlation of multiple rheological parameters,the dynamic yield behaviors present little influence on the deformation of the 3D printed structure,while the static yield stress presents the reverse phenomenon,which influences the structural deformation obviously.In conclusion,the introduction of nano-silica into the 3D printed white Portland cement-based materials can well control the rheological properties,and improve the printed structures and early mechanical properties.