Effectiveness of Asphaltic Concrete Overlays of Rigid Highway Pavements Using LTPP SPS-6 Data

Pavement rehabilitation, a key aspect of pavement management, aims at improving pavement condition and extending pavement life. As such highway agencies strive to identify and implement effective rehabilitation practices to preserve the large investments made in the highway pavement infrastructure and increasingly do so using observational and experimental studies. LTPP’s SPS-6 experiment was set up to assist highway agencies identify effective and efficient treatments for rigid pavement rehabilitation. Using data from LTPP database and other sources, the present paper evaluated the effectiveness of five rehabilitation treatments under this experiment. The performance measures used are the increase in pavement condition and the treatment service life. For each rehabilitation treatment, the evaluation involved the construction of post-treatment performance curves. The study determined that the pre-treatment condition is a significant predictor of the post-treatment performance. The paper also suggests that for a given traffic load, increasing climate severity translates into lower treatment effectiveness. Also, for a given climate severity, increasing traffic load translates into lower treatment effectiveness. At high traffic loads, there seem to be little difference in treatment effectiveness across various climate severities. The “crack-and-seat existing pavement and 8-inch AC overlay” was adjudged the most effective in terms of both service life and increase in average pavement condition, irrespective of SHRP regional group. The methodology and findings of this paper can be useful to highway managers who seek to assess or compare the effectiveness of their treatments and to carry out the pavement management functions of life-cycle analysis and work planning.