Don't forget the sand, which is technically an aggregate[1]. Using the wrong sand is a classic mistake being rediscovered in China: http://www.wired.com/2013/0

Don't forget the sand, which is technically an aggregate[1]. Using the wrong sand is a classic mistake being rediscovered in China: http://www.wired.com/2013/03/poor-quality-chinese-concrete-could-lead-to-skyscraper-collapses/ http://www.wired.com/2013/03/poor-quality-chinese-concrete-c... [1]-The concrete recipes I remember always had sand and rocks, gravel and/or pebbles (depending on local availability)