The linked article makes this clear: > In case you need a refresher, cement is a...

		thinkpad20 on March 24, 2015 \| parent \| context \| favorite \| on: China used more cement in 3 years than the U.S. di... The linked article makes this clear: > In case you need a refresher, cement is a powdery lime-and-clay substance that is combined with water and gravel or sand to make concrete.