This report represents a study undertaken to determine the life cycle, load characteristics, and associated costs of a representative sample of the oldest rigid and flexible pavements designed in louisiana (1963-1967) using the aasho guide for design of pavement structures. Project selection resulted in a sampling of two classes of roads designed and constructed during this period--interstate route jointed concrete pavements and secondary route asphaltic concrete pavements. An index, termed the load rate index, was developed to compare actual and designed rates of equivalent single-axle loading (eal) at any point in the life of a pavement. The total accumulated eal was also compared with the total designed eal. The typical jointed concrete pavement had not reached end of life by its 20th year (1989), having carried its design eal. The effects of factors of safety usedin the original design were removed by relating design eal to actual section thickness. The typical flexible pavement in the sample reached end of life within 14 years. The performance of these pavementswas charcterized by cracking and settlement within the cement-treated bases. Total project costs (construction plus maintenance) prior to end of life were expressed in terms of cost per mile, per eal ($eal-mile), to represent pavement value or return on investment for each route class. It is concluded that expressions of pavement value to be incorporated into louisiana's pavement management system shouldinclude the rate and quantity of designed load actually carried before end of life. This paper appears in transportation research record no. 1215, Pavement management and rehabilitation.
Abstract