Optimizing the Performance of Microsurfacing Treatments in Flexible Pavements and Assessing Its Effects on Moisture Damage

Abstract

Louisiana’s $6.3 million microsurfacing program is amongst the largest microsurfacing programs in the United States. As microsurfacing seals the road surface, the effectiveness of this treatment in such a setting has been a concern in recent years by linking it to moisture damage caused by the trapped moisture underneath the pavement especially in areas with shallow groundwater table. Furthermore, the cost-effectiveness and optimal timing of microsurfacing applications are also not well established for the south-central United States. The objective of this study was to assess the short-term and long-term effects of microsurfacing treatments and to evaluate whether microsurfacing is a major contributor to moisture damage. Field performance of 27 sections where microsurfacing treatments were applied between 2003 and 2008 was monitored for at least eight years. Results indicated that microsurfacing is most effective in addressing rutting damage as compared with the other performance indicators. Microsurfacing extended the service life of the pavements by 4.9–8.8 years. The effectiveness of microsurfacing was found to be optimum when applied to pavements with pre-treatment conditions ranging from 80 to 85. Results of this study also showed that microsurfacing-treated sections exhibited higher percentage of moisture damage as compared with the untreated sections in all the districts. Therefore, an in-depth assessment of the effects of microsurfacing on moisture damage in asphalt pavements is recommended.