07-11-2012, 04:54 PM
Green Concrete
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Overview of Green Concrete
Environmental aspects of concrete
CO2 in Ordinary Portland Cement
Alternative binders
Alkali activated cements
Calcium sulfoaluminate cements
Other alternatives
Challenges and opportunities for green cement
Alternative binders
Alkali activated cements
Calcium sulfo-aluminate cements
Other options
(calcium sulfate, magnesia, and blended OPC cements)
Alkali activated cements
Alumino-silicate bonding phase
(alumina rich source material and an alkali silicate solution)
Termed geocements, aluminate cements
Source materials can be either pozzolanic or non-pozzolanic
Fly ash, blast furnace slag, metakaolin
Calcium sulfoaluminate cements
Known as sulfoaluminate, ettringite, or belite-sulfoaluminate cements
High alumina, low energy, high early strength, rapid setting, long-term durability
Source material
Limestone, bauxite or alumina clays, and gypsum
Clinker result of calcinated source materials
Hydration products
Early strength: ettringite, long-term strength: C-S-H