UTC 2022 Funding - Cycle 1 Research Projects

Project No.: CY1-LTU-02
Title: A Screening Tool for Assessment of Moisture-Induced Damage of Asphalt Mixes Containing RAP Based on Molecular Dynamics Simulation
Performing Institution: Louisiana Tech University
Principal Investigator: Andrew Peters and Nazimuddin Wasiuddin, Louisiana Tech University
Start and Anticipated Completion Dates: 10/1/2023-9/30/2024
Project Description: In this project, the research team seeks to develop a screening tool for the assessment of moisture-induced damage potential of asphalt mixes containing reclaimed asphalt pavement (RAP). Molecular dynamics (MD) simulation, a widely accepted physics-based numerical simulation technique, will be used to examine the compatibility between asphalt binders and aggregates, including RAP. Because rejuvenators are used frequently in asphalt mixes containing RAP, particularly with increased RAP contents, rejuvenators will be included in the MD simulations. Adhesive interactions between asphalt binder and aggregate, in the presence of moisture, will be used as an indicator of compatibility or resistance to moisture-induced damage. Because of the limited budget and timeline, existing asphalt, aggregate, and rejuvenator molecules will be used in the MD simulations. Atomistic molecular dynamics will be used to simulate the binder and aggregate interfaces and determine the interaction energies and adhesive strengths between the binder and the aggregate. Using Bell’s model, the pulling velocity 𝑣=𝑣0𝑒𝑥𝑝(𝑓𝑥𝑏𝑘𝑏⁄𝑇), where 𝑥𝑏 is the distance between the equilibrium states and the transition state, and 𝑣0=𝜔0𝑥𝑏𝑒𝑥𝑝⁡(−𝐸𝑏𝑘𝑏⁄𝑇), where f is the external pulling force, 𝑥𝑏 is the distance between the equilibrium state and the transition state, 𝑘𝑏 is Boltzmann’s constant, T is temperature, 𝜔0 is the natural vibration frequency, and 𝐸𝑏 is the adhesion energy, will be quantified. The adhesive strength obtained from the MD simulations will be compared with the direct tensile strength determined in the laboratory using a pneumatic adhesion tensile testing instrument.
Click to read more.