A virtual simulation experiment teaching scheme centered on interface fatigue damage was designed for senior undergraduates in civil engineering. This scheme addresses the difficulty in understanding the fatigue damage evolution law of multiphase interfaces in grouted asphalt concrete (GAC) under cyclic loading and the inability of traditional experiments to observe the meso-damage process. It transforms cutting-edge research results into operable inquiry-based teaching content to cultivate students’ interdisciplinary thinking and innovation ability.

The experimental teaching follows a progressive logic of “theoretical foundation → parameter calibration → modeling and solution → law analysis → innovation and expansion.” It comprises five specific steps. First, the theoretical foundation is established by systematically teaching the basic theory of the bilinear cohesive zone model (CZM), the fatigue damage evolution criteria under cyclic loading, and the development principles of the USDFLD user subroutine. This foundation provides students with the necessary mathematical and programming knowledge. Second, for parameter calibration, students are guided to acquire the material’s meso-structure through the GAC original section image collection. Key CZM parameters (strength, stiffness, and fracture energy) are obtained via interface pull-out tests. The generalized Maxwell model is used to characterize asphalt viscoelasticity, and the Prony series is fitted to obtain the relaxation parameters needed for ABAQUS. The CZM interface simulation parameters are finally determined using an inversion method. Third, in the modeling and solution phase, students build a meso-scale representative volume element (RVE) model of the multiphase material (including asphalt, aggregate, and geopolymer) in ABAQUS. Cohesive elements are embedded to represent the interfaces. The core task is to develop and integrate a USDFLD user material subroutine to embed the fatigue damage model numerically. After the subroutine is verified, cyclic loading is applied to the model to calculate the solution. Fourth, for law analysis, students extract the stress–strain responses and cumulative damage values of the cohesive elements from two interface types (asphalt–geopolymer and asphalt–aggregate) from the simulation results. Through data curve analysis, they reveal the three-stage law of damage accumulation under cyclic loading and compare the impact of different interfaces on the overall fatigue life of the material. Fifth, during the innovation and expansion phase, students are guided to independently design a meso-scale parameter sensitivity analysis scheme. They change key parameters like interface properties or aggregate/grout attributes to explore the influence mechanism of these parameters in the macroscale fatigue damage evolution process and final failure life of the composite material.

On the basis of the inquiry practice in the virtual simulation experiment, students drew clear conclusions. The greatest improvement in the fatigue resistance of GAC is obtained by increasing the interface ITZ fracture energy, followed by the interface ITZ bond strength, while the geopolymer flexural strength has a relatively minor impact. Students also gained a deep understanding that the interface, as the transition zone between material phases, directly determines the macroscopic mechanical properties. Teaching practice data show that 94.3% of students independently completed the entire process of simulation modeling and subroutine integration, and 48.1% further proposed innovative suggestions such as interface modification and parameter optimization.

This experiment effectively transforms cutting-edge research results into inquiry-based teaching content. It considerably enhances students’ innovative competence in applying multidisciplinary knowledge to solve complex engineering problems. It provides a practical paradigm for conducting cutting-edge, inquiry-based experimental teaching in civil engineering materials courses.