Incorporating truck speed effect on evaluation and design of flexible pavement systems

Abstract

The ever increasing traffic volumes and density on road network worldwide coupled with accelerated deterioration of road conditions continuously motivate pavement engineers to seek improvements to existing pavement analysis and design methods. Most current pavement analysis and design procedures either assume static loading or perform quasi-dynamic analysis by characterizing asphalt materials using loading frequency on specimen to get complex moduli for input into response models. Correct simulation of pavement response to dynamic loading is critical to mechanistic analysis of pavement systems. The present study used a Traffic Speed Deflectometer (TSD) to induce the dynamic loading to the flexible pavement systems at predetermined speeds and wander. Elastic surface deflections from eight different flexible pavement sections were measured using the Multi-Depth Deflectometer (MDD). The study investigated and proposed a methodology for normalising deflections measured at different moving load speeds using Speed Adjustment Factors (SAFs). The SAFs showed that the influence of speed on the pavement response to dynamic loading varied significantly depending on the type of the flexible pavement systems.