• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.89-91
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• 2012

The purpose of this study is to investigate the mechanical property and carbonation resistance of concretes using surface treated lightweight aggregate. In order to evaluate mechanical property and carbonation resistance, slump, compressive strength, and carbonation depth are tested. Slump of concretes using surface treated lightweight aggregate measured 120~125mm, which are lower than slump of NWAC. Compared to compressive strength of NWAC, compressive strength of concretes using surface treated lightweight aggregate showed a level of 82.8~95.9%. In carbonation resistance test, carbonation depth of concretes using surface treated lightweight aggregate measured 10.2~11.3mm, which are lower than carbonation depth of NWAC. As a result, it is found that compressive strength is decreased slightly but carbonation resistance is improved, in case of using surface treated lightweight aggregate.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.271-273
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• 2012

This paper is to investigate the effect of waste cooking oil(WCO) on carbonation resistance of high volume fly ash and blast furnace slag concrete. WCO and paint were applied for carbonation resistance materials. As expected, the application of WCO to the concrete help it reduce carbonation depth remarkably, regardless of mixture types. This may be due to the fact that WCO makes the capillary pore block by activating saponification. It is found that the degree of carbonation reduce due to WCO is much higher than the case by Paint.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.81-82
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• 2020

In this study, after applying a silicate-based impregnation and polymer-based coating to fire damaged high strength concrete, carbonation resistance was evaluated to compare and evaluate the carbonation depth according to the type of surface repair materials. As a result of the experiment, it was confirmed that the carbonation resistance was increased in the case of the concrete with the surface repair materials compared to the control specimen without the surface repair materials. In particular, in the case of the polymer-based coating agent, it was confirmed that the carbonation hardly progressed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.45-47
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• 2011

Finishing materials used during the construction of reinforced concrete structures aid in providing resistance to carbonation and help ensure the durability of a structure. However, detailed examinations of this phenomena using data gained from long-term outdoor exposure are not only lacking, but also are not taken into account as factors affected by the local environment. In this research, the velocity coefficient in terms of carbonation is compared as a difference according to the local region and the averaged annual temperature, and the carbonation-preventive effects of finishing materials are analyzed. As an outcome of this study, the results of long-term carbonation can be evaluated from carbonation resistance R induced by an acceleration carbonation test.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.60-61
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• 2019

Concrete carbonation is one of the factors that reduce the durability of concrete. In modern times, due to industrialization, the carbon dioxide concentration in the atmosphere is increasing, and the impact of carbonation is increasing. So, it is important to understand the carbonation resistance according to the concrete compounding to secure the concrete durability life. In this study, we want to predict the concrete carbonation velocity coefficient, which is an indicator of the carbonation resistance of concrete, through the deep learning algorithm, and to find the activation function suitable for the prediction of carbonation rate coefficient as a process to determine the learning accuracy through the deep learning algorithm. In the scope of this study, using the ReLU function showed better accuracy than using other activation functions.

• Journal of the Korea Institute of Building Construction
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• v.14 no.1
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• pp.21-28
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• 2014

The purpose of this study is to investigate the mechanical properties and carbonation resistance of concretes using lightweight aggregate coated surface finishing materials. To evaluate the mechanical properties and carbonation resistance of concrete, slump, air amount, air-dried unit volume weight, compressive strength, and carbonation depth are tested. In terms of the unit volume weight of concrete, air-dried unit volume weight of concrete using coating lightweight aggregate was measured as $1,739{\sim}1,806kg/m^3$. When using coating aggregate, compressive strength of concrete at 28 days was measured as much as 82.7~95.9% of the compressive strength using non-coating aggregate. It is found that compressive strength tends to decrease with coating lightweight aggregate. However, all concretes using coating lightweight aggregate except O-LWAC satisfied the criteria for 28-day compressive strength suggested in KS. The measurement of carbonation depth when the water-repellent agent was used found that carbonation depth was reduced by as much as 2.6~6.1%. On the other hand, when using polymer waterproof agent, carbonation depth was reduced by as much as 8.6~12.0%. Consequently, to improve carbonation resistance, polymer waterproof agent was more effective than water-repellent agent. In particular, epoxy showed the most outstanding performance.

• International Journal of Concrete Structures and Materials
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• v.18 no.1E
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• pp.17-22
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• 2006

Artificial cracks were made in the cover concrete of specimens embedding ten types of steel rebars of different Cr contents. The research aims for developing Cr-bearing steel rebars resistant to macrocell corrosion environments induced by cracking in cover concrete. The cracks were subjected to intensive penetration of carbon dioxide (carbonation specimens) to form macrocells. The carbonation specimens were then treated with accelerated corrosion curing, during which current macrocell corrosion density was measured. The corrosion area and loss from corrosion were also measured at the end of 105 cycles of this accelerated curing. The results of the study showed that Cr-bearing steel with Cr content of 5% or more suppressed corrosion in a macrocell corrosion environment induced by the differences in the pH values due to carbonation of cracked parts. Cr-bearing steels with Cr content of 7% or more are proven to possess excellent corrosion resistance.

• Journal of the Korean Society of Safety
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• v.29 no.4
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• pp.103-109
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• 2014

In this study, two types of water-soluble sulfur, LSA and LSB, were developed and the influence of the water-soluble sulfur on the mechanical properties and durability of concrete were experimentally evaluated. In order to evaluate mechanical properties and carbonation resistance of concrete with water-soluble sulfur, compressive strength test, flexural strength test, bonding strength test, and carbonation resistance test were performed. Compressive strength of only concrete with 1% LSA was increased while that of concrete with LSB was proportionally increased with the higher LSB dosage. On the other hand, flexural strength of concrete with LSA and LSB was increased by 12-41% and 36-74%, respectively. Carbonation resistance of concrete with water-soluble sulfur were increased by 25-66%. As a result, it should be noted that the water-soluble sulfur can not only solve the demerit of sulfur concrete but also offer the durability of sulfur concrete.

• KIEAE Journal
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• v.7 no.4
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• pp.127-133
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• 2007

As a fundamental study on the corrosion resistance of reinforced concrete structures using Natural Inorganic Minerals exposed to carbonation environment, The test specimens were concrete(W/C=60%) with Natural Inorganic Minerals content of 0%, 10%. Accelerated carbonation and autoclave corrosion accelerated curing were then conducted with them. The corrosion resistance of steel in concrete with Natural Inorganic Minerals content of 0%, 10% was examined by corrosion form, half-cell potential, polarization resistance, corrosion area and weight loss after 24 hours of autoclave corrosion accelerated curing.The results of the study showed that as for steel in concrete with Natural Inorganic Minerals content of 10%, the corrosion resistance was more excellent than steel in concrete with Natural Inorganic Minerals content of 0%.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.293-298
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• 1997

Corrosion of steel reinforcing in concrete deteriorated by freezing/thawing and carbonation was characterized. Concrete specimens were prepared using various kinds of cements such as ordinary portland cement (type I), low heat portland cement (type IV, belite rich cement), sulphate resistance portland cement (type V), blast furnace slag portland cement and ternary blended cement. Of various cements, type V and type IV with lower $C_3A$ content revealed better steel corrosion resistance after freezing/thawing and carbonation. $C_3A$ content in cement might affect freezing/thawing resistance in sea water.