Abstract

The production of portland cement, the world’s most used building material, is responsible for approximately 5 percent of manmade CO₂ emissions. Reduction of CO₂ from cement manufacturing can be achieved through a variety of strategies, of which one of the most urgent and important is partial substitution of the cement clinker with supplementary cementitious materials. In this chapter, the problem of CO₂ emissions from cement production is summarized along with the possible strategies to reduce emissions. New and emerging sources of supplementary cementitious materials to meet increasing demand are presented, including reclaimed and remediated fly ashes, natural pozzolans, and calcined clay-limestone blends.