Developing Low CO sub(2) Concretes: Is Clinker Replacement Sufficient? The Need of Cement Use Efficiency Improvement

Cement industry is under stress for mitigating CO2 emissions: it is responsible for around 5-7% of total global emissions due to the production that went over 2x10[sup 9] tones in 2006. And this prospect will aggravate since it is expected, for 2050, an increase of 2.5 times, which will make cement industry guilty for more than 30% of CO[sub 2] emissions. Main actions for decreasing emissions are: energy efficiency in kilns, use of alternative fuels and clinker substitution. These, however, are not capable to decrease emissions in a satisfactory way. CO[sub 2] capture is expensive and could increase cement costs. There is a potential to reduce significantly the cement content on concrete, being possible to increase concrete production without increasing cement production and CO[sub 2] generation. This can impact significantly on concrete environmental load to global warming and also in its cost, making possible to increase popular habitations construction mainly in some developing countries which have a lack of different sort of infrastructure where concrete technology is still dominant.