Davis Tucker says:
Cement is mainly used to make concrete, and is sort of the "active ingredient" in concrete - it is combined with sand and gravel in roughly fixed proportions. So cement production can be considered a rough proxy for the total amount of construction going on in a country.Link
The growth in China, from 1 Gigatons to 1.3 Gigatons in two years is mindboggling, even India and Russia are interesting... and there's more to the story than that too.
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. His new book is Maker Dad: Lunch Box Guitars, Antigravity Jars, and 22 Other Incredibly Cool Father-Daughter DIY Projects