Exploring creep and recovery behavior of hot mix asphalt field cores with multi-sequenced repeated load test

Abstract

Rutting is known as a major distress in hot-mix asphalt (HMA) pavements. In order to fully characterize the creep and recovery behaviors of HMA mixes under varying loading conditions at high temperatures, a newly modified multi-sequenced repeated load test with a greatly improved sampling rate of 500 in a second was developed and performed on HMA field cores. Various indicators, including maximum strain, recovered strain, un-recovered strain, resilient modulus (Mr), non-recoverable creep compliance (Jnr), and percent recovery (R%) were proposed to investigate the visco-elastic properties of asphalt mixture. The stress-dependencies of these indicators were analyzed, besides, the correlation and ANOVA analyses were also conducted. Based on the analysis results, it is found that all analyzed indicators except Mr show significant stress-dependency; the vast majority of strain can be recovered (R > 99%), and an increased stress plays a negative role in recovery behavior. The facts indicate that only in a wider stress domain can the visco-elastic characteristics of HMA mixes be fully understood, furthermore, Jnr and R are superior to other indicators in statistically differentiating the viscous and elastic properties of different asphalt mixtures, respectively.