on aggregate..

  1. when we ask the belgians n dutch to dig islands of sand off cambodia indonesia malaysia why nobody suggest put aussie sand back?
  2. when we tear down an old building its essentially a concrete quarry. man made rock with steel bars insideā€¦ do we crush it to aggregate size as new aggregate(n recycle the steel i imagine)? or put inside wire cages n use for sea reclamation? else all that man-made rock go where?
  3. he say something like 40% of concrete is pre cast now. how about use industrial waste water for casting n curing? once my man-made rock forms, the toxic shit is locked inside forever?