Asphalt can weaken and break down over time.  This is due in Michigan to freezing and thawing.  The winters are severe in the Midwest and this leads to heaving of the asphalt.  The asphalt then cracks and slowly breaks eventually leaving a deep hole.  At River City this type of damage is repaired with high grade asphalt patching materials.  A liquid tack is applied to help the new asphalt bond to the existing asphalt.  The newly laid material is then pressed with a heavy asphalt roller.  This assures that the patch will be sturdy and will have the best chance of withstanding the freezing and thawing of the coming winters.  At River City this type of work is done regularly, and the owner of the company is ALWAYS on site.