alt Hacker NewsConcrete is cement plus aggregate (it doesn't have to be sand; it could be gravel, for example). Coarse aggregates wouldn't work well in this, but it would be cool for a followup video where sand is used.
The wikipedia pages suggests that this is more prolery referred to as "foam mortar" or "foam cement"
You could say the aggregate is air and the cement still performs its role as a binder, it binds all the air bubbles into a stable matrix. Hence "aerated concrete".