The joints had been fixed and fresh asphalt laid over 40-year-old concrete on Interstate 94 between downtown Minneapolis and Brooklyn Center. But before traffic even started to roll over the new multimillion-dollar freeway, the pavement buckled in five places from the 90-degree June heat, leading to higher costs and more delays. The incident highlights a wrenching debate that is playing out among state officials trying to stretch limited transportation money to fix or replace as much roadway as possible. In Minnesota and in many other states, transportation funding has lagged as road conditions have deteriorated.