I've had lots of blow outs in the dim and distant past, every single one was a recap (tip work very hard on tyres)...basically the old tread remains ground off and a new tread bonded on, usually it was casing failure but very little remained to be examined by the time you had stopped.

I had experience of a nearly new recap failure only a few weeks ago, my company do not run these things so how it came to be on one of our trailers is a mystery yet to be explained, the company insist on proper tyres of good make, our failure rate is near enough zero despite maximum weight running 24/7, the tyre in question i luckily spotted going down before it caused an issue, sure enough the recap was separating.

Those treads you see are almost always retreads of one sort or another, a recap is just the tread replaced, you can still see all the details of the original casing on the sidewalls, a full remould puts a new skin on the sidewalls too complete with the remoulders branding and remould serial number, there are good remoulds and tat, much like everything else.

That driver was a brave man. I hope he wasn't injured.