Don't bother covering it with anything. The damage has been done.

The real danger here is that a piece of machinery got near your tree. Any tree you intend to keep should be protected during construction. A minimum rule of thumb for root disturbance is 1.5 feet for every inch of diameter. Keep all machinery, vehicles, material storage, etc. off this area, and no excavation or grading should be done in this area.

If any of these activities have already occurred in this area, have an arborist come out and address the compaction and root loss. You can find an arborist at treesaregood.com

The primary damage to your oak is below ground. What a shame that builders and architects don't know this.

keep wound clean and free of insects and it will repair itself, if you wish you might wrap the tree in the area of the wound with breathable medical tape to keep out bugs but still allow the wound to breath.

most Walgreens carry this

Here is a link that might be useful: Medical tape