Geopolymer Concrete: An alternative green construction material
Global Warming is the international problem that have to be solved, immediately, and need the collaboration from all countries around the world. As we know that the problem come from several segments, for example, using of fuel in transportation system or in the industrial factory including the Portland cement manufacturing industry which is a major segment that releases the greenhouse gas to environment. In the Portland cement manufacturing process, exploding limestone mountain is the necessary step in order to get the raw material. The air pollution, the haze problem, and the environmental problem would be occurred from the exploding. After that, the big rock will be crushed, ground, and then roasted in the rotary kiln to produce the Portland cement.
This process consumes a lot of fuel; therefore, the carbon dioxide (CO2) will be released from the kiln. Moreover, the limestone composes of calcium carbonate as its main chemical composition, which will be changed to carbon dioxide after burning. A researcher, Joseph Davidovits, have ever reported a simple formula to calculate the carbon dioxide releasing from the Portland cement manufacturing industry that “1 ton of cement = 1 ton of CO2”. The recent information from The Office of Industrial Economics, Thailand, showed that the total 35 million tons of Portland cement was produced for using within the country and also exported in 2008. This means that about 35 million tons of carbon dioxide was released to the air, only from Thailand during a year while another countries is not yet included. Not only the carbon dioxide but also air pollution, haze problem, and environmental problem as described above, too.
This could be conclude that reducing the Portland cement consumption, the better environment. From the fact above, researchers try to find a way out by using pozzolanic material as the partially cement replacement in concrete. However, the Portland cement is still needed as the main part in the mixture. Fortunately, a new kind of concrete-like material named “Geopolymer concrete” was, recently, developed. The conventional concrete and geopolymer concrete have a similar engineering properties but no more using the Portland cement in the mixture. Moreover, industrial wastes such as fly ash and biomass ash could be used as geopolymer’s raw material. This is another prominent point in using of geopolymer in environmental aspect. At the moment, geopolymer concrete is in during of research and not yet ready for the real work in Thailand. However, this is a good sign for construction industry to develop buildings that good and green at the same time.
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