Costs and effectiveness of flexible pavement treatments: Experience and evidence

The authors investigated the effectiveness and costs of preventive treatment techniques for flexible pavements. Based on survey results from 29 state departments of transportation (DOTs), it was found that the expected pavement life extension caused by these treatments follows the order of thin hot-mix asphalt (HMA) overlay, microsurfacing tied with chip sealing, slurry sealing, and crack filling/sealing. The reported costs follow the order of thin overlay, microsurfacing, and chip sealing tied with slurry sealing, whereas costs of crack sealing/filling cannot be directly compared. The authors also analyzed data from 81 Long-Term Pavement Performance (LTPP) program specific pavement studies (SPS) experiments, which were specifically designed and constructed to study the effectiveness of pavement treatments. Based on paired t-tests, it was found that all the treatments reduced international roughness index (IRI) with statistical significance. The authors then pooled the data from all the control sections and created a pseudo control section and subsequently developed a linear regression model for it. By comparing the effects of treatments with this pseudo control section, the authors found that the approximate life extension of the pavement sections benefited from these treatments is as follows: thin overlay for 5.4 years, chip sealing for 1.9 years, crack sealing for 1.7 years, and slurry sealing for 1.1 years.