Field study on understanding effects of micro-trenching on structural performance of asphaltic pavement

Abstract

The paper presents a performance case study to investigate the effects of micro trenching (MT) technique on structural performance of asphaltic pavements. The study was conducted on a flexible pavement in the city of Mumbai to place underground optic fiber cables. The structural performance of asphaltic pavement was determined using Benkelman beam deflection (BBD) and indirect tensile strength (ITS) test before and after MT. The study includes both dry and wet sections in MT application to understand the effect of moisture conditioning on structural performance of asphaltic pavement. The effect of time after MT reinstatement i.e. 4 hrs and five days were also considered during structural evaluation. In addition, the study presents detailed discussion on the number of steps followed right from site selection to final MT reinstatement (i.e. selection of MT alignment using ground penetrating radar (GPR) survey, depth and width selection of MT, coring, reinstatement etc.). The BBD test result showed that minimal difference was observed in structural capacity of asphaltic pavement before and after five days of MT. Likewise, ITS results exhibited that bond between grouting material (SBS 2511 modified concrete named as SBSMC) and hot mix asphalt (HMA) layer was found to be intact. Finally, the study suggests various precautions and s uggestions for field execution of MT technique. It is expected that the advantage of MT technique in terms of structural performance along with other benefits such as costeffectiveness, environmental friendly, rapid laying etc. will encourage the application of MT technique as compared to other similar techniques.