Recurring freezing and thawing conditions this season have led to a greater number of potholes, frost heaves and other signs of road deterioration, state and local officials said. Officials blame road conditions on this year’s premature spring-like conditions, which were bookended by freezing temperatures. The thaw-freeze cycle causes the ground to swell and contract, forming frost heaves and cavities under the surface that eventually collapse into potholes. Those weather conditions also weaken and crack asphalt, especially on aged roads that don’t drain well, said Brian Burne, a highway maintenance engineer for the Maine Department of Transportation. “As the ground starts to thaw, you get all this moisture trapped in ice.