Hot mixed asphalt (HMA) overlay is one of the commonly used methods for rehabilitating deteriorated pavements. The Nevada Department of Transportation (NDOT) uses HMA overlays as a rehabilitation technique for the majority of the states flexible pavements. One major type of distress influencing the life of an overlay is reflective cracking. In the past, NDOT has experimented with a number of techniques to reduce the impact of reflective cracking on HMA overlays like cold in-place recycling, reinforced fabrics, stress relief courses and mill and overlay. A number of projects were constructed under each category. This paper evaluates the long-term field performance of the various NDOT reflective cracking mitigation techniques used on 33 different field projects on flexible pavements. The performances of the various projects were analyzed in terms of the fatigue, transverse and block cracking measurements from the NDOTs Pavement Management System (PMS) data. Additionally, the statistical approach called Principal Component Analysis (PCA) was used to asses the effectiveness of each of the reflective cracking techniques. This study indicates that cold in-place recycling and mill and overlay were the most effective treatments for reflective cracking of HMA overlays over HMA pavements under Nevadas conditions except when the existing pavement is experiencing severe alligator cracking. In such situations it is recommended that the HMA pavement be subjected to reconstruction or full depth reclamation.
Samenvatting