I've used Nationwide for cars but not for semis. For heavy trucks, I'd go with Freedom Heavy Haul. They specialize in that. Check their website for details.

My buddy Dave had something similar happen on a job last summer. He was running the jointer and a 2 foot chunk just popped out like a puzzle piece. He had to quickly mix up a little cold patch and trowel it in before the customer noticed.

Hot shoeing isn't just tradition, it's proven. Glue shoes might work for a few months but they don't support the foot the same way. Nails actually compress the hoof wall and stimulate blood flow, glue just sits there like a bandaid. Your mare not holding nails sounds more like a hoof quality issue or a farrier problem than a reason to ditch the oldest method that's kept horses sound for centuries.