The pilot decided to make an unscheduled landing at an aerodrome enroute to check a problem with the aircraft. On touchdown he noticed steel pickets on either side of the runway and reapplied power. During the go-around the left wing tip struck a picket, the aircraft yawed and then collided with other pickets, before the aircraft was brought to a stop. The aerodrome had been closed for reconstruction work. White crosses were placed on the runway and adjacent to the windsock. The pilot had not advised Flight Service of his intended landing. The aircraft nose attitude on approach reduces forward visibility and the pilot did not see the white crosses on the runway. The aircraft yawed as power was applied for the overshoot.