3D打印煤矸石砂浆流变性能、打印性能与力学性能研究

Research on Rheological Properties,Printability and Mechanical Properties of 3D Printing Coal Gangue Mortar

为了拓展煤矸石的应用范围,利用煤矸石骨料部分或完全取代(质量分数为0%、50%和100%)3D打印砂浆中的天然砂,对比研究了煤矸石骨料的加入对3D打印砂浆流变模型、流变性能、可打印性能和力学性能的影响。结果表明,煤矸石的加入会降低3D打印砂浆的力学性能,但是在煤矸石掺量为100%时28 d的抗压强度仍可超过30 MPa,满足力学性能的要求。掺入煤矸石骨料后的3D打印砂浆的流变性能符合修正的Bingham模型,静态屈服应力、动态屈服应力均随煤矸石掺量的增加而增大。在掺量为100%时,经时静态屈服应力增速快,经时流动度和经时动态屈服应力增速慢,这表明煤矸石的引入明显提高了3D打印砂浆的可打印性。

To expand the application scope of coal gangue.In this study,gangue aggregate is used to partially or completely replace(mass fraction of 0%,50%and 100%)nutural sand in 3D printing mortar,and the effect of gangue aggregate addition on the the rheological model,rheological properties,printability,and mechanical properties of 3D printing mortar was systematically examined.The results reveal that,the addition of coal gangue reduces the mechanical properties of 3D printing mortar,but when the coal gangue content is 100%,the compressive strength at 28 d still exceeds 30 MPa,meeting the requirements for mechanical properties.The rheological properties of 3D printing mortar mixed with gangue aggregate conform to the modified Bingham model.Both static yield stress and dynamic yield stress increase proportionally with higher gangue doping.Notably,when the gangue doping is 100%,the growth rate of time-dependent static yield stress is fast,while the growth rates of time-dependent flowability and time-dependent dynamic yield stress are slow.This indicates that the introduction of gangue significantly improves the printability of 3D printing mortar.