Tire = LT275/65R20. After 20 minutes on surface streets in 98° weather, entered freeway and heard a ‘thumping’ sound every second at about 45 mph. Appeared to be the freeway but after accelerating to about 55 mph a loud bang was heard and the tire blew. This was a catastrophic failure where the tread fully separated from the wheel and did substantial damage to the side and wheel well of the truck. The rim was also damaged beyond repair.