A new method to determine maintenance and repair activities at network-level pavement management using falling weight deflectometer

Abstract

Pavement condition assessment at network level requires structural evaluation that can be achieved using Falling Weight Deflectometer (FWD). Upon analysing FWD data, appropriate maintenance and repair methods (preser­vation, rehabilitation or reconstruction) could be assigned to various pavement sections. In this study, Structural Condi­tion Index (SCI), defined as the ratio of Effective Structural Number (SN_eff) to Required Structural Number (SN_req), was used to determine if a pavement requires preservation or rehabilitation works (i.e. preservation SCI > 1, rehabilitation SCI < 1). In addition to FWD deflection data, SCI calculation requires pavement layer thicknesses that is obtained using GPR with elaborated and time consuming works. In order to reduce field data collection and analysis time at network-level pavement management, SCI values were calculated without having knowledge of pavement layer thicknesses. Two regression models were developed based on several thousand FWD deflection data to calculate SN_eff of pavements and resilient modulus (M_R) of their subgrades. Subgrades M_R values together with traffic data were then used to calculate SN_req. Statistical analysis of deflection data indicated that Area under Pavement Profile (AUPP) and the deflection at distance of 60 cm from load center (D₆₀) parameters showed to have strong correlation with SN_eff and M_R respectively. The determination coefficients of the two developed models were greater than those of previous models reported in the literature. The significant result of this study was to calculate SN_eff and M_R using the same deflection data. Finally, imple­mentation of the developed method was described in determining appropriate Maintenance and Repair (M&R) method at network level pavement management system.

Keyword : Falling Weight Deflectometer (FWD), Structural Condition Index (SCI), Maintenance and Repair (M&R) method, network-level pavement management, structural assessment, subgrade MR