Effect of basalt fiber on properties of asphalt and asphalt mixture

Abstract

Asphalt mixture is the surface material of flexible pavement and semi-rigid pavement. It directly bears the influence of climate conditions and traffic load, and is prone to aging and fatigue damage. Therefore, using reinforcing agent to improve the performance of asphalt mixture is the long-term goal of researchers.This paper aims to study the effect of basalt fiber on asphalt viscosity and mechanical properties of asphalt mixture. Firstly, by testing the basic properties of asphalt binder with different fiber content, the viscosity characteristics of fiber + asphalt composites are analyzed by using the modified Einstein viscosity equation. The research shows that basalt fiber has obvious toughening effect on asphalt, and the penetration and softening point indexes are suitable to evaluate the viscosity properties of fiber + asphalt composites.Secondly, the effects of different fiber content on the water stability and splitting tensile strength of asphalt mixture are analyzed. The results show that the maximum content of basalt fiber should not be greater than 0.4%; With the increase of fiber content, the splitting strength of asphalt mixture increases, but the increase is not obvious when the content is > 0.30%, while the stiffness modulus continues to increase, indicating that the deformation resistance of asphalt mixture is enhanced after adding fiber. Based on the micromechanics theory of composite materials, the basic principle of basalt mineral fiber improving the strength performance of asphalt mixture is explained. The research shows that basalt mineral fiber can significantly improve the performance of asphalt mixture.

Numerical Simulation of Steel Fiber Pull-Out Process Based on Cohesive Zone Model and Unified Phase-Field Theory

“…According to the existing research [25], in the process of steel fiber pull-out, not only does interface damage between the steel fiber and the concrete matrix lead to the fiber falling off, but the fiber falling off due to damage to the concrete matrix is the main damage form. To more intuitively and accurately characterize concrete matrix damage, this paper adopts the phase-field regularized cohesive zone model (PF-CZM), which was proposed based on the unified phase-field theory.…”

“…According to the scanning electron microscope image of the fiber damage form in ref. [25], it can be seen that the matrix's damage is the main damage form for fiber pull-out. Therefore, in this section, it is assumed that the interface bond strength between steel fibers and the concrete matrix is high (τ max = 3 MPa) and no debonding damage occurs, and the influence of the mechanical properties of the concrete matrix itself on the mechanical properties of steel fiber pull-out is analyzed.…”

“…Zong Y W et al [24] established a three-phase finite element model for steel fiber pull-out and analyzed the influence of different factors such as the steel fiber embedment depth, interface layer thickness, and steel fiber length-diameter ratio on the pull-out characteristics of steel fiber. Yang C C et al [25] found that the fiber falling off due to the failure of the matrix itself is the main failure form of steel fiber pull-out according to a real bending-pulling failure fracture electron microscope scan image, and established two pull-out models based on the cohesive zone model to analyze the influence of different strengths of the interface layer and the matrix itself on the pull-out properties of the fiber.…”