Break mineral aggregate for rebuild (7)
I believe the answer is:
restore
'rebuild' is the definition.
(thesaurus)
'break mineral aggregate' is the wordplay.
'break' becomes 'rest' (a rest is taking a break).
'mineral aggregate' becomes 'ore' (I've seen this before).
'rest'+'ore'='RESTORE'
'for' acts as a link.
(Other definitions for restore that I've seen before include "Bring back; renovate" , "hand it back?" , "Make good, reinstate" , "Bring back to health" , "Bring back, reinstate" .)