ABSTRACT
ABSTRACT: This paper describes an analytic approach that can be used to evaluate and propose rehabilitation schedules based on economic, performance, and environmental considerations for various types of pavements managed by the Illinois State Tollway Authority. A Mixed-Integer Nonlinear Program (MINLP) is formulated to model the agency’s life-cycle cost and environmental impacts where the decision set consists of the maintenance overlay type and the thickness of the overlay proposed on a temporal scale over a planning horizon. The problem requires interaction of the integer and continuous variables that leads to MINLP formulation. Considering practical implications of the problem, the continuous variables are bounded into a fi nite and discrete set, while the integrality constraints are relaxed. The objective and constraints of the problem can be alternated to suit the needs of the agency, which may be interested in minimizing environmental impacts and restricting the cost to the agency, or vice versa, over the pavement life-cycle.
