Effectiveness of steel reinforcing nettings in combating fatigue cracking in new flexible pavement systems

This paper investigates the effectiveness of steel paving mesh as reinforcement for hot-mix asphalt (HMA) in new flexible pavement systems. Two sections of the Virginia Smart Road were instrumented and constructed incorporating three different types of steel reinforcement. Instrument responses to vehicular loading, combined with finite element (FE) modeling, were used to evaluate the effectiveness of steel reinforcement in enhancing flexible pavement performance and resisting fatigue cracking initiating at the bottom of the HMA layers. After the FE models were calibrated based on instrument responses to vehicular loading, a comparison was established between reinforced and unreinforced cases. In Section L, where steel reinforcement was used on top of the cement-treated open-graded drainage layer, the fatigue performance of the considered pavement structure improved by 6 to 55% in the transverse direction, and by 25 to 82% in the longitudinal direction. In Section I, where steel reinforcement was used at the bottom of the HMA layers, the range of improvement for the pavement structure was between 15 and 257% in the transverse direction, and between 12 and 261% in the longitudinal direction. It is important to emphasize that because steel reinforcement was used in two different pavement structures and at different locations in the pavement system, no comparison between the performance and effectiveness of two types of steel reinforcement could be investigated. The contribution of steel reinforcement to the structure is believed to be of the utmost importance after crack initiation.