Total gravel and stone (9)
I believe the answer is:
aggregate
'total' is the definition.
(synonyms)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for aggregate that I've seen before include "Accumulation" , "Material mixed with cement to form concrete" , "Collective total - a great egg (anag)" , "Collected" , "piece of granite perhaps" .)