Resumen de A hard sell?: Metakaolin in high-performance concrete
Industrial Minerals
According to Transparency Market Research, the global metakaolin market was valued at $91.8m in 2012 and is expected to reach $124.2m by 2019, expanding at a compound annual growth rate (CAGR) of 4.4%. According to California, US-based materials technology firm Demeter Technologies Inc., energy consumption of flash-calcined metakaolin material is up to two and a half times less than that of traditional calcining. [...]the metakaolin product will contain unreactive glass. When ordinary Portland cement reacts with water it produces a hard cementitious substance but also releases calcium hydroxide (Ca(0H)2 ), an unwanted by-product which can lead to concrete cancer ** and other problems. Brayton Point Cooling Towers, Massachusetts, US (2012) Metakaolin was used in the concrete of two cooling towers in a coal-burning power plant adjacent to the sea, providing reduced permeability, improved chloride resistance and increased durability and strength. References: Dr Denis Bezard, Newchem AG Scientific World Journal: "Effects of Different Mineral Admixtures on the Properties of Fresh Concrete", by Sadaqat Ullah Khan, Muhammad Fadhil Nuruddin, Tehmina Ayub and Nasir Shafiq Dezeen architecture and design magazine The International Journal of Current Engineering & Technology The Concrete Centre "Tall Buildings" The 2012 NRMCA Supplementary Cementitious Materials Use Survey Ruben Snellings, Vlaams Institute of Technology, Belgium. *Frank Hart is the owner and director of First Test Minerals Ltd. **Concrete cancer is a term given to the reaction which occurs over time in concrete between the highly alkaline cement paste and the reactive non-crystalline (amorphous) silica found in many common aggregates
