Effect of construction tolerance on flexible pavement performance

Abstract

The consistency on design and construction is an important factor on pavement performance. Layer thicknesses play an important role in the response of flexible pavements on service. Differences on layer thickness between as-designed and as-built are significant in the performance of a pavement structure. Colombian highway construction specification allows tolerances in pavement layer thicknesses which may shorten the pavement service life. A study was performed to investigate whether the allowed construction tolerances have significant effect on flexible pavement performance. Two flexible pavement structures were analyzed; one structure included a cement-treaded base layer. For each structure, all layer thicknesses were varied simultaneously within the construction tolerances by using statistical simulation techniques, a total of 100 variations were performed for each structure. The performance of the resulting modified structures was evaluated using the companion software of the Mechanistic-Empirical Pavement Design Guide (MEPDG). The parameters considered in this study were roughness, bottom-up cracking, and rutting. The results show that reductions on thickness in the asphalt layer and the cement-treaded base layer, within construction tolerances, have significant effect on pavement performance. Variations on layer thicknesses, within construction tolerance, of granular base and sub-base have no significant effect on pavement performance.