Viscoelastic, Viscoplastic, and Damage Modeling of Asphalt Concrete in Unconfined Compression

TLDR

The study calibrated a comprehensive constitutive model for asphalt concrete incorporating viscoelasticity, viscoplasticity, and irreversible micro‑structural damage under unconfined compression. The model was calibrated using small‑strain dynamic modulus, cyclic creep‑recovery, and constant‑rate‑of‑strain tests across a broad range of temperatures, loading rates, and stress levels, and then validated by predicting additional constant‑rate‑of‑strain responses at unseen conditions. The model accurately predicted asphalt concrete behavior across varied temperatures and strain rates, demonstrating its realistic simulation capability.

Abstract

A comprehensive constitutive model for asphalt concrete was calibrated that included viscoelasticity, viscoplasticity, and irreversible micro-structural damage in unconfined compression. Three different types of laboratory tests were designed and performed to calibrate each of these response components. Small-strain dynamic modulus tests were used to calibrate the undamaged linear viscoelastic properties. Cyclic creep and recovery tests to failure were performed to calibrate the viscoplastic properties. Constant-rate-of-strain tests to failure were used to calibrate the damage behavior. These tests were performed at a wide range of temperatures, loading rates, and stress levels. Upon calibration of each individual response, the model was validated by predicting the results of other constant-rate-of-strain tests at temperatures and strain rates different from those used in the calibrations. The predictions for these different conditions indicate that the comprehensive model can realistically simulate a wide range of asphalt concrete behavior.