Corporate pilot reported landing on a closed runway at SGH where the closed markings were not identifiable. NOTAM on the closure was not published before departure.

Narrative

Checked NOTAMs before leaving for SGH and Airport Runway 6/24 wasn't NOTAMed closed at this time. In route received AWOS weather and no mention of runway closure at the end of Weather readout recording. Columbus Approach never mentioned that the Airport Runway 6/24 at SGH was closed when we stated we were going to do the visual approach for Runway 6. On final approach I made a 15;10; and 5 mile position reports stating we were inbound landing; Runway six. No one at the airport Unicom acknowledged our calls or advised that Runway 6/24 was closed.Upon landing; the Captain commented about debris on the approach end of the runway and called Unicom about the debris and was told that the debris is a couple of bricks and small yellow X. We can see the wind had blown it askew. Corrective action on this situation was discussed between the crew and corrective action will be to check NOTAMs via iPad in flight after listening to the local AWOS broadcast to confirm and catch any last minute NOTAMs that come up while in route. On the Airport side; the little yellow X they use needs to be larger; more secure; and more visible to pilots on final approach. The one they used just looked like debris blown onto the runway.