Mechanisms and modeling of waste/cement interactions International Workshop, May 8 to 12, 2005, Meiringen, Switzerland

摘要

Traditionally cement research has primarily focused on the development of safe and improved construction materials, centered on the use of Portland cement or one of its permitted variants. Cement chemists furthered our understanding of the hydration process, the kinetics, the minerals formed, the thermodynamic stability of the mineral assemblages, interactions with aggregate materials and long-term changes in mineralogy.Recent developments in the cement industry have increased the complexity of cementitious materials. Supplementary cementing materials, including coal combustion fly ash, iron blast furnace slag, silica fume, metakaolin, etc., greatly modify the bulk chemistry, and hence the min eralogy, of the solid matrix. Using wastes to replace coal, oil or gas normally used to pyroprocess the cement, saves energy and is a convenient way of eliminating wastes: examples include solvents, contaminated/used oil, rubber, paper or plastics. Contaminated soils may also be added to the kilns as a raw material. While organic contaminants are destroyed in the kiln, an increase in metal concentrations is possible. Stakeholders need to be able to assess the impact of elevated metal concentrations on cement properties and the environment.