Development of Treatment Performance Models for Flexible Pavements

Louisiana has 18,000 miles of roadways that deteriorate over time due to increased traffic loads, environmental factors and aging. The Louisiana Department of Transportation and Development (LADOTD) has been spending significant capital for rehabilitation and maintenance treatment programs for these roadways. These treatments such as Overlay, Chip Seal and Micro surfacing delay the Replacement of the pavement by increasing its life. Performance models for these treatments are necessary to find the most cost-effective treatment and the application time of the treatment for any particular pavement. Till now, a full scale performance assessment for above mentioned treatments and cost-effectiveness analysis are not conducted which would provide LADOTD the advantage of selecting the most cost-effective treatment for Flexible Pavement. The objective of this research is to build performance models for all above mentioned treatments for Flexible Pavement which will facilitate LADOTD to determine the most cost-effective treatment and the application time of the treatment for Flexible Pavement. Various LADOTD databases were thoroughly searched for time series distress data and historical data of projects. Climatic Indices (Temperature Index, Low Temperature Index and Precipitation Index) are developed. 972 roadway sections are found to have sufficient data to build models for all above mentioned treatment types. Performance models for all five major distress types such as International Roughness Index (IRI), Rut, Fatigue Cracking, Transverse Cracking and Longitudinal Cracking are developed for the treatments mentioned above in this research. These models are found to be the function of highway functional classification, cumulative ESAL, thickness of the pavement, temperature and precipitation. A software is promised to LADOTD that will evaluate the most cost-effective treatment for any Flexible Pavement section using these performance models