Here is a reference to a question asked in class about the GHG emissions from Cement – [Louise]

This states that the cement industry accounts for 5% of the 2012 Global CO2 emissions. Cement is the primary ingredient of concrete.

‘Concrete is the second most consumed substance on Earth after water.  On average, each year, three tons of concrete are consumed by every person on the planet.’

‘Though “cement” and “concrete” are often used interchangeably, concrete is actually the final product made from cement. The primary component of cement is limestone. To produce cement, limestone and other clay-like materials are heated in a kiln at 1400°C and then ground to form a lumpy, solid substance called clinker; clinker is then combined with gypsum to form cement.

Cement manufacturing is highly energy – and – emissions intensive because of the extreme heat required to produce it.  Producing a ton of cement requires 4.7 million BTU of energy, equivalent to about 400 pounds of coal, and generates nearly a ton of CO2. Given its high emissions and critical importance to society, cement is an obvious place to look to reduce greenhouse gas emissions.’

http://blogs.ei.columbia.edu/2012/05/09/emissions-from-the-cement-industry/