• Journal of the Korean Society of Safety
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• 제23권5호
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• pp.97-104
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• 2008

This study was intended to evaluate the permeable performance through a change of reinforcing materials, curing condition, durability evaluation and permeability test, and to select the reinforcing material which could reduce the durability and water tightness from it, as the study for considering how the change of the outside's environment factors that the concrete structure actually contacted with impacted the concrete's durability especially the permeability by referring to such the background of the study. Accordingly, it was judged that evaluating the permeability by considering the severe environment condition where the concrete structure was placed in was more reasonable than measuring the existing permeability coefficient conducted in the sound state for the permeability evaluation of actually-used concrete structure. In this study, it also could be known that the specimen of hybrid fiber reinforced concrete which mixed the long and short steel fiber was the most effective for water tightness enhancement in severe environmental conditions.

• Journal of The Korean Society of Agricultural Engineers
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• 제51권6호
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• pp.97-103
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• 2009

This study was performed to evaluate the strength and durability properties of recycled polymer concrete using unsaturated polyester resin and recycled aggregates. Unsaturated polyester resin, natural and recycled aggregates and fly ash were used. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate sizes (5-10 and 5-25 mm) and unit binder contents (10% and 12%). Tests for the compressive and flexural strength, freezing and thawing and durability for 20% sulfuric solution were performed. The compressive and flexural strength of recycled polymer concrete were in the range of 85~97 MPa and 17.9~20.8 MPa, respectively. The strengths of recycled polymer concrete using recycled aggregate have similar or slightly decreased compared to polymer concrete using natural aggregate. After 300 cycles of freezing and thawing, weight decrease ratio and durability factor of recycled polymer concrete were in the range of 0.13~1.42% and 94~99, respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.581-584
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• 2006

The durability of reinforced concrete structures is severely degraded by mainly corrosion due to seawater attack and chloride ion diffusion in concrete. The deterioration of durability causes high repair cost for maintenance of marine concrete structure. In this paper, high-durability materials for prevention of rebar corrosion are investigated to promote the durability in marine concrete structures. For these, the effect of the mineral materials addition(SF, FA and BFS), the modified steel(stainless and coating steel). and corrosion inhibitors are compared.

• International Journal of Concrete Structures and Materials
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• 제4권1호
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• pp.17-23
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• 2010

The feasibility of the use of scrap tire rubber in concrete was investigated. The tests conducted in two groups: replacing of coarse aggregates with crumb rubber and cement particles with rubber powder. To distinguish the properties of new concrete, the following mechanical and durability tests were designed: compressive, tensile and flexural strength, permeability and water absorption. Rubber addition could affect the concrete properties depend on the type and percentage of the rubber added. Although the rubber addition modifies the mechanical characteristics of concrete in a way, but higher rubber content could not be useful. Concrete durability showed more dependency to the type of rubber instead of percentage of rubber. Moreover, to optimize the mechanical and durability of rubberized concrete, the useful percentage of rubber has been recommended.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.147-150
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• 1999

Glossing Exposure Concrete is a high quality architectural concrete, i.e., appearance of natural stone and a marbling effect concrete to achieve high quality glassy reflective surface for outer wall of the building. In this study to obtain the conservation and durability of gloss of the "glossing exposure concrete" we developed a from practice and the best mix proportion and derived the optimistic removal time of form to bring out the durable glassy reflective surface and durable concrete. Hereby with the "glossing exposure concrete" obtained, we investigate the accelerate carbonation and accelerate durability test to evaluate the durability factor of this type of concrete.is type of concrete.

• Journal of the Korea Institute of Building Construction
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• 제13권2호
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• pp.139-147
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• 2013

The purpose of this study was to investigate the durability performance of concrete that includes rice husk ash. Chloride diffusion coefficient obtained through a rapid chloride penetration test and depth of $CO_2$ penetration obtained through a rapid carbonation test were used to evaluate latent durability. Durability characteristics for rice husk ash replacement and age were determined. Through the experiment, it was found that when the replacement ratio of rice husk ash was increased from 0% to 10%, the compressive strength of concrete containing rice husk ash was similar to that of concrete containing silica fume. This shows that the durability performance of concrete containing rice husk is excellent compared to other concretes containing admixtures.

• Computers and Concrete
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• 제15권4호
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• pp.589-606
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• 2015

It is well-documented that the major deterioration of coastal RC structures is chloride-induced corrosion. Therefore, regional investigations are necessary for durability based design and evaluation of the proposed service life prdiction models. In this paper, four reinforced concrete jetties exposed to severe marine environment were monitored to assess the long term chloride penetration at 6 months to 96 months. Also, some accelerated durability tests were performed on standard samples in laboratory. As a result, two time-dependent equations are proposed for basic parameters of chloride diffusion into concrete and then the corrosion initiation time is estimated by a developed probabilistic service life model Also, two famous service life prediction models are compared using chloride profiles obtained from structures after about 40 years in the tidal exposure conditions. The results confirm that the influence of concrete quality on diffusion coefficients is related to the concrete pore structure and the time dependence is due to chemical reactions of sea water ions with hydration products which lead a reduction in pore structure. Also, proper attention to the durability properties of concrete may extend the service life of marine structures greater than fifty years, even in harsh environments.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2006년도 추계 학술논문 발표대회 논문집
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• pp.151-154
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• 2006

It is generally referred that life cycle of concrete construction is depend on whether durability of concrete is obtained or not. Nevertheless, it has not been yet applied that new material and technology to improve durability of concrete such as seaside concrete construction. In this study, chemical agent which is capable of improving durability added to 2 types seaside concrete mixs and evaluated engineering properties such as slump, air content, setting time and compressive strength. Besides shrinkage crack with an restraint condition and chloride ion penetration tests were executed to measure resistance of concrete added chemical agent and then compared non-added. It was appeared that engineering properties and resistant for chlorides was possible to improved. But resistant for shrinkage crack was not noticeable improvement than non-added. Therefore it is necessary that more consideration and following study to improve durability aspect to shrinkage crack and chlorides resistant.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 1998년도 가을 학술발표회 논문집(I)
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• pp.121-126
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• 1998

Increased costs for cement have favoured the use of supplementary cementing materials in concrete. The use of fly ash in concrete has increased in the past few years. Concrete have been selected for use as a construction material in aggressive environment. The use of fly ash as concrete material has a role, and an understanding of its effect on concrete durability is essential to its correct and economical application. In this study, durability tests including permeability, freezing thawing resistance for Korean fly ash concrete are conducted. The durability characteristics of fly ash concrete are discussed.

• Advances in concrete construction
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• 제8권2호
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• pp.119-126
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• 2019

This paper reports an experimental investigation conducted to evaluate the durability performance of concrete mixtures prepared utilizing blends of Type I Portland cement (OPC) and natural pozzolans (NPs) obtained from three different sources in Saudi Arabia. The control concrete mixture containing OPC alone as the binder and three concrete mixtures incorporating NPs were prepared keeping water/binder ratio of 0.4 (by weight), binder content of $370kg/m^3$, and fine/total aggregate ratio of 0.38 (by weight) invariant. The compressive strength and durability properties that included depth of water penetration, depth of carbonation, chloride diffusion coefficient, and resistance to reinforcement corrosion and sulfate attack were determined. Results of this study indicate that at all ages, the compressive strength of NP-admixed concrete mixtures was slightly less than that of the concrete containing OPC alone. However, the concrete mixtures containing NP exhibited lower depth of water penetration and chloride diffusion coefficient and more resistance to reinforcement corrosion and sulfate attack as compared to OPC. NP-admixed concrete showed relatively more depth of carbonation than OPC when subjected to accelerated carbonation. The results of this investigation indicates the viability of utilizing of Saudi natural pozzolans for improving the durability characteristics of concrete subjected to chloride and sulfate exposures.