Concrete’s role as CO2 absorber may be underestimatedPublished on May 19th, 2009 | By: Peter Wray
The new (June) issue of the Journal of Environmental Engineering is all about “Recent Developments in CO2 Emission Control Technology including lots of ceramic-related information.
For example, there is an article that suggests that concrete/Portland cement is not quite the villain some have thought when it comes to CO2 emissions. CO2 production in making cement and concrete is a concern and comes from three sources: the decarbonation of limestone, kiln fuel combustion, and from vehicles used to carry and distribute the cement and concrete.
Older studies have indicated that small amounts of CO2 can be slowly absorbed through the formation of calcite. Since concrete structures are often in place for years, the speed of this reaction isn’t really a problem (although it can cause problems when rebar is present). But this new study asserts that significant amounts of C02 is also being absorbed through non-calcite mechanisms, increasing the total CO2 removed from the atmosphere and lowering concrete’s overall carbon footprint.
From the abstract: “This research focuses on other carbon dioxide sequestration species within concrete. It is hypothesized, and has been shown in some cases, that many other dissolved carbon dioxide complexes exist within the cement paste matrix, as they do in many aqueous-based systems and also that carbonate species other than calcite may exist. It is shown that carbon dioxide species, other than calcite, do exist in cement paste samples in amounts that are significant with respect to the stoichiometric potential for reversing the calcination process.
Other technical papers included in this edition include:
- Liquid-Impregnated Clay Solid Sorbents for CO2 Removal from Postcombustion Gas Streams
- Effects of Steam Addition on the Properties of High Temperature Ceramic CO2 Acceptors
- Sintering and Reactivity of CaCO3-Based Sorbents for In Situ CO2 Capture in Fluidized Beds under Realistic Calcination Conditions
- Mechanisms of Neutralization of Bauxite Residue by Carbon Dioxide
- Modification of CaO by Organic Alumina Precursor for Enhancing Cyclic Capture of CO2 Greenhouse Gas
Adding . . . the JEE is a scientific journal that, like most others, requires either 1) a subscription, or 2) payment per article.
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