- Title
- Experimental study on effects of CO₂ concentrations on concrete carbonation and diffusion mechanisms
- Creator
- Cui, Hongzhi; Tang, Waiching; Liu, Wei; Dong, Zhijun; Xing, Feng
- Relation
- Construction and Building Materials Vol. 93, p. 522-527
- Publisher Link
- http://dx.doi.org/10.1016/j.conbuildmat.2015.06.007
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2015
- Description
- In this paper, concretes of different grades were exposed to five different CO₂ concentration levels (2, 10, 20, 50 and 100% by volume) using accelerated carbonation test methods. The relationship between the depth of concrete carbonation and CO₂ concentration was investigated. The diffusion mechanisms of CO₂ gas in concrete were analysed through the scanning electron microscopy (SEM) observations. Experimental results showed that, under the same carbonation age, the increase of carbonation depth was found to be high when concrete samples were exposed to low CO₂ concentrations (i.e. 2-20%); and low when the samples were exposed to high CO₂ concentrations (i.e. 50-100%). The reason for this is mainly due to the microstructure change caused by concrete carbonation, which makes the surface layer denser thus lowering the rate of CO₂ diffusion into concrete. SEM results showed that carbonation decreased the porosity of concrete by clogging up the pores and reducing the pore sizes. It is believed that the diffusion mechanisms of CO₂ into concrete under high and low CO₂ concentration levels would be different.
- Subject
- concrete; carbonation; CO₂ carbonation; diffusion mechanism; microstructure
- Identifier
- http://hdl.handle.net/1959.13/1326917
- Identifier
- uon:25538
- Identifier
- ISSN:0950-0618
- Language
- eng
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