基于三维细观模型的玄武岩纤维混凝土数值模拟

Numerical simulation of basalt fiber concrete based on 3D mesoscale model

基于玄武岩纤维-砂浆界面的相关理论和试验数据,提出一种建立小直径纤维-骨料混凝土细观模型的方法,研究玄武岩纤维混凝土的损伤演化和纤维对混凝土的增强机理。通过建立的随机纤维-骨料混凝土三维细观模型预测和验证了玄武岩纤维混凝土的立方体抗压强度、劈裂抗拉强度、轴心抗压强度和抗折强度等力学性能,并从细观角度分析了混凝土的损伤演化和纤维的作用机理;建立不同分布形式、不同纤维掺量的随机纤维-骨料混凝土模型,研究了细观模型的力学稳定性及纤维掺量对混凝土的影响规律。结果表明:基于该方法建立的细观模型在预测玄武岩纤维混凝土静态力学性能方面具有较高的可靠性;混凝土损伤首先发生在较大基体变形的薄弱界面过渡区,并随着荷载的增加延展、联接,最终导致试件的整体破坏;玄武岩纤维具有抵抗基体变形的约束作用,对混凝土力学性能影响明显;纤维掺量小于1.5%时,掺量越大,增强效果越明显。

Based on the theory and experimental data of basalt fiber-mortar interface,a small diameter fiber-aggregate concrete model was proposed,the damage evolution of basalt fiber reinforced concrete(BFRC)and the mechanism of fiber reinforced concrete were studied.The mechanical property of BFRC,such as cubic compressive strength,splitting tensile strength,axial compressive strength and flexural strength,were predicted and verified by establishing a three-dimensional mesoscale random fiber-aggregate concrete model,then the damage evolution of concrete and the action mechanism of fiber were analyzed from the mesoscale view.The random fiber-aggregate concrete model with different distributions and different fiber contents was established,then the stability of mesoscale model and the effect of fiber contents on concrete were studied.The results show that the mesoscale model based on the method has high reliability in predicting the static mechanical property of BFRC.The damage of concrete occurs in the weak interfacial transition zone of the larger matrix deformation initially,then extends and connects with the increase of loading,and finally leads the overall failure of specimen.Basalt fiber has the restraint function of resisting matrix deformation,and obviously affects the mechanical property of concrete.When the fiber content is less than 1.5%,the mechanical property increases with the increase of fiber content.