Research on the microscopic mechanical properties of basalt fiber asphalt concrete based on nanoindentation

Abstract

[Objective] To investigate the micromechanical properties of basalt fiber asphalt concrete(BFAC), [Methods] a nanoindentation tests with finite element numerical simulations was conducted to thoroughly examine the mechanical responses of the constituent phases of BFAC. A four-phase three-dimensional model comprising the asphalt matrix, aggregate, aggregateasphalt transition interface, and fiber was constructed using Abaqus software. The static implicit algorithm was employed to simulate the indentation process, thereby capturing the evolution patterns of load-displacement response, modulus, hardness, and creep behavior for each phase. [Results] The findings reveal significant variations in the mechanical properties of the BFAC phases. The Young' s moduli of the asphalt matrix, aggregate, fiber, and transition interface were measured at 1. 73 GPa, 76. 69 GPa, 120. 60 GPa, and 34. 39 GPa, respectively. The numerical simulations exhibited a high degree of concordance with the experimental curves, with Young's modulus errors below 5%, thereby validating the efficacy and accuracy of the model in analyzing the micromechanical behavior of BFAC. [Conclusion] The asphalt matrix in BFAC demonstrated the lowest modulus and hardness, with the most pronounced plastic deformation and creep response. In contrast, the aggregate and fiber exhibited high modulus, high hardness, and superior deformation resistance, with creep displacements all below 70 nm. The transition interface' s performance was intermediate between the aggregate and asphalt matrix. Field analysis indicated that the displacement, stress, and strain fields at the indentation point exhibited a distribution characteristic of high values beneath the indenter and low values in the far field. The contours of displacement, stress, and strain expanded elliptically inward, with their magnitudes gradually attenuating with increasing depth. Additionally, the study elucidated the influence mechanism of indenter geometry on the indentation response. Compared to the Berkovich indenter, the spherical indenter, due to its smaller contact area, with a smaller slope in the loading curve. increased the indentation depth by approximately 12% to 28% at maximum load. These findings provide valuable insights for the structural design and performance optimization of hydraulic asphalt concrete materials.

Keywords

basalt fiber asphalt concrete / nano-indentation / numerical simulation / micro-mechanical properties / influencing factor / Young's moduli / transition interface