I've not googled this, so take it FWIW.

I know there is a movement to use old tires in the production of
concrete, they burn them and turn them into something called fly ash,
which is used in the manufacuring of concrete. I'm not sure how the
process works exactly in fact the tires might not turn into fly ash,
but may just be used as fuel?

Secondly there are companies who turn tires in rubber flooring.