What are the advantages and disadvantages of using thin asphalt overlays for pavement rehabilitation?

Thin asphalt overlays, typically less than 2 inches thick, are used for pavement rehabilitation. They offer several advantages and disadvantages. Cost-effectiveness is a key advantage. Thin overlays are less expensive than thicker overlays or reconstruction, making them a cost-effective option for extending pavement life. Reduced construction time is also a benefit, thin overlays can be placed quickly, minimizing traffic disruptions. Improved ride quality occurs as thin overlays can improve pavement smoothness and reduce roughness, enhancing the driving experience. Surface sealing is another advantage, thin overlays can seal minor cracks and prevent water infiltration, protecting the underlying pavement structure. However, thin overlays also have limitations. Limited structural capacity is a key drawback. Thin overlays provide minimal structural improvement and are not suitable for pavements with significant structural deficiencies. Reflective cracking is a concern, thin overlays are susceptible to reflective cracking from underlying cracks in the existing pavement. Short service life is another disadvantage, thin overlays typically have a shorter service life than thicker overlays or reconstruction. Limited ability to correct distresses is a limitation, thin overlays can only address minor surface distresses and cannot correct significant rutting or deformation. In summary, thin asphalt overlays are a cost-effective option for extending the life of pavements in good structural condition, but they have limited structural capacity and are susceptible to reflective cracking. They are best suited for pavements with minor surface distresses and a sound underlying structure.