The high temperature reached 90 degrees in Madison Thursday, breaking a record more than 30 years old.  All of the heat caused buckled pavement in some locations around southern Wisconsin.  The Wisconsin Department of Transportation reports a portion of eastbound Highway 12 near Lake Delton was closed to traffic at about 9:30 a-m when the pavement buckled.  Repairs were made and the road was reopened about 90 minutes later.  That section of Highway 12 had similar problems last summer.  Officials have been trying to figure out what’s causing the problem.  A stretch of U-S Highway 51 in McFarland was closed while the same type of problem was fixed Thursday afternoon.