Construction delay impact on asphalt pavement structural performance: the case of N6 highway in Ghana

Abstract

Cost, environmental, and social impacts of road construction delay have been widely investigated, but not its impacts on pavement structural performance. This study conducted pavement structural analysis and distress survey on a section of the N6 Highway in Ghana that had experienced more than a decade of construction delay to examine the impact of the delay on pavement structural performance. The pavement structure and its variants (representing different construction stages) were mechanistically modeled in WESLEA, a layered elastic pavement analysis program, to determine critical pavement strains for fatigue and rutting performance prediction. Also, various pavement structural design scenarios, simulating different construction stages and traffic loading, were analyzed using the American Association of State Highway and Transportation Officials (AASHTO) flexible pavement design procedure to examine the effects of construction delay on pavement structural capacity. The mechanistic analysis showed that trafficking a partially completed pavement considerably increases critical strain levels and exposes the pavement to a higher risk of fatigue and rutting damage. Large structural capacity deficits were obtained for the incomplete pavements: the thinner the in-situ pavement structure and the longer the construction delay, the greater the structural capacity deficit and the greater the damage risk. Opening incomplete pavement structures to traffic for a long time must be avoided because the associated high critical strains and inadequate in-situ structural capacity can induce premature failure, as corroborated by the distress survey findings. Construction staging specifications must be strictly enforced, while construction delay must be avoided and, if impossible, its effects minimized through effective project construction management.