• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.1029-1034
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• 2001

The effects of binder content and silica sand content on the freezing and thawing resistance of lightweight polymer concrete are examined. As a result, the mass loss and pulse velocity of lightweight polymer concrete decrease with increasing binder content and silica sand content. The relative dynamic modulus and durability factor of lightweight polymer concrete reaches minimum at a silica sand content of 50% and a binder content of 28%, and is inclined to increase with increasing binder content and silica sand content.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.625-630
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• 2002

The availability of natural aggregates has decreased in recent years due to depleting reserves. From the viewpoint of energy and resources saving, it may be advantageous to use the waste concrete as construction aggregates. The purpose of this study is to analyze petrographic and chemical properties of recycled aggregate, and to investigate the resistance of concrete to rapid freezing and thawing by using replacement ratios (0, 10, 20, 30, 40, 50, 60, 70, 100% ) of recycled aggregate.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.433-436
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• 2008

Deterioration in the concrete structure are due to carbonation, chloride ion attack and frost attack. Therefore, concrete structure is needed to surface protection for increase durability using silicate impregnants. Thus, this study is concerned with self-cleaning and durability of silicate hydrophilic impregnants of concrete structure using lithium and potassium silicates. From the experimental test results, lithium and potassium silicates have a good properties as a carbonation resistance. Lithium and potassium silicates make good use of hydrophilic impregnants of concrete structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.3
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• pp.125-133
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• 2011

The requirement for durability of concrete bridge deck is increasing as the deterioration for the concrete bridge deck exposed to severe environment has been increased. For this reason, the concern about high-durable concrete is being high. Recently, a metakaolin is highly spotlighted as new admixture because its strength and durability are equivalent to silica fume. On the other hands, there are few researches for the metakaolin concrete bridge deck in domestic. So many various long-term data on the mechanical property and durability is needed to apply metakaolin concrete at the concrete bridge deck construction field. This study is aim to evaluate the long-term mechanical properties and durability of metakaolin concrete bridge deck with curing age. Mechanical properties are estimated by the compressive and flexural strength, and the drying shrinkage, the chloride resistance, the scaling, and freezing and thawing characteristics are compared with curing age. According to the results, when the metakaolin concrete is used, the development of compressive and flexural strength proceed in both the early and old ages. It is also improved the resistance of chloride penetration, freezing and thawing in concrete. It was showed that replacement of metakaolin was efficient for the reduction of the drying shrinkage.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.144-151
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• 2023

In this study, a database was established by collecting experimental results on various concrete mixtures subjected to freeze-thaw cycles, based on which an artificial neural network-based prediction model was developed to estimate durability resistance of concrete. A regression analysis was also conducted to derive an equation for estimating relative dynamic modulus of elasticity subjected to freeze-thaw loads. The error rate and coefficient of determination of the proposed artificial neural network model were approximately 11% and 0.72, respectively, and the regression equation also provided very similar accuracy. Thus, it is considered that the proposed artificial neural network model and regression equation can be used for estimating relative dynamic modulus of elasticity for various concrete mixtures subjected to freeze-thaw loads.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.13-24
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• 1993

The influence of the bubble structure and strength characteristics on the freeze-thaw resistance of high strength concrete is investigated by the laboratory experiment. The test conditions are formed in the manner that water is continueusly supplied externally and the specimens were received severe weather actions from ordinary to significantly low temperatures. The experiments are performed in two stages. In the first stage, the relation between the durability to frost action and the bubble structure is analyzed especially with respect to the water-cement ratio and the amount of air. The AE and non-AE concrete specimens made of ordinary portland cement are used in the test. In the second stage, the non-AE concrete specimens using vibratory compaction to improve the durability to frost action, and the high watertight specimens of rapid hardening portland cement to increase their initial strength are produced and tested. The degree of watertightness of the specimens is determined by measuring the permeability of the specimens and the bubble structure of the high watertight concrete is also estimated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4542-4551
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• 2013

Recently, much attention has focused on the study of eco-friendly concrete using recycled by-products for protecting marine ecosystem and durability of concrete exposed to marine condition. This study evaluated the durabilities of 4 different type of concrete mixtures(Control, Marine, Porous, New slag) with the seawater resistance by marine environment exposure experiment and freeze-thaw resistance, resistance to chloride ion penetration considering severe deterioration environment. In this study, we conducted seawater resistance using compressive strength according to the age(7/28/56 days) of specimen and curing conditions(standard(fresh water), tidal, immersion, artificial seawater). The results show that compressive strength of concrete exposed to marine environment exposure condition was lower than those of the standard curing condition. Also, compressive strength of New slag using eco-friendly materials for protecting marine ecosystem was lower than those of other concretes, there is need to improve the performance of New slag. The results for freeze-thaw resistance showed that all mixtures have excellent, but the Porous and New slag were lower than others. Also, the more improved resistance to chloride ion penetration than those of the Marine was measured in the New slag regardless of curing condition.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.151-152
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• 2015

Concrete parking slab is often deteriorated severely after winter season because of concrete's freezing and thawing phenomenon. In this study, some methods to improve resistance against freezing-thawing is experimentally tested.: 1) concrete strength, 2) air content in concrete, 3) saw-cut effect and finish material. After experiment, in case of no finishes, 24MPa concrete with 4% air content is tested best result in terms of relative elastics modulus among testes ones. In case of concrete with finishes, all specimens are improved regardless of finishes compared to concrete with no finishes. Improvement degree compared to no finish is as follows : Polyurea > Resin-mortar > hardener and the number of improvement degree is 5, 4, 2% respectively. Further work is required considering construction site condition such as gaining water on surface and remicon in order to reflect site condition.

• International Journal of Highway Engineering
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• v.12 no.1
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• pp.47-54
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• 2010

This study had a focus on investigating technical validity of Two-Lift Concrete Pavements which had never been constructed in Korea in order to olve the problem of existing concrete pavements. This study found out the application of Steel Fiber Reinforced Concrete (SFRC) which was one of ew techniques. Also, optimal steel fiber contents and pavement thickness were determined. This study also measured compressive strengths, lexural strengths, toughness indexes, tensile strengths and fatigue strengths to estimate the performance of SFRC of according to results of aboratory experiments, slumps and air contents of concrete specimens the standards satisfied and compressive strengths to open traffic. At bending ests, Toughness Index of SFRC increased but flexural strength didn’'t increase as compared with non-steel fiber concretes. And, energy absorption of SFRC was very good and SFRC showed improvement in freezing and thawing resistances. To complete this research, we will evaluate the pplication methods and performance of SFRC at field section.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.111-118
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• 2016

The scaling of concrete caused by the combined effects of frost and deicing salt is one of the principle causes of damage to transportation infrastructure in cold-climate regions. In this study, to evaluate the factors affecting scaling resistance of concrete, the relationship between the properties of concrete, such as the mechanical properties and pore structure, and scaling resistance was examined experimentally. The test results showed that the scaling resistance was strongly dependent on the absorption properties of concrete, but not on the compressive strength. Furthermore, it is believed that both the spacing factor and specific surface of the air voids was not a good parameter for evaluating the scaling resistance of concrete. SGC concrete was less durable than OPC and SFC concrete with respect to the scaling resistance in the scope of the present study.