• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.699-702
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• 2005

This study evaluates the properties of porous concrete for pavement according to content of silica fume and steel fiber. The results of the test indicate that in every condition, the void ratio and the coefficient of water permeability of porous concrete for pavement satisfy both the domestic standards and proposition values. Among the properties of strength, the compressive strength satisfies the standards in the specification of KNHC as for every factor of mixture but in the case of the flexural strength, more than $0.6vol.\%$ of steel fiber satisfied the JCI proposition values. The case when silica fume and steel fiber are used simultaneously presents the strongest durability and Noise Reduction Coefficient is 0.48 to prove that it possesses almost $50\%$ sound absorption.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.61-64
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• 2005

Recently to repair the structure of deteriorated concrete, LMC rehabilitation method is introduced. however, this method has the possible risks of brittle failure depending on bond performance of the interface. the prediction of interfacial behavior becomes essential to protect the failure. all of the studies which have been done about this field are only about material property such as strength, durability, bond. there is not enough data and studies about structural behavior and numerical analysis. therefore, in this study A flexural nonlinear analysis model of ABAQUS was proposed to predict the load-deflection response, interfacial stress, and ultimate strength. The parameter study showed that overlay thickness was a main influencing factor to the behavior of RC beam overlayed by LMC.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.489-492
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• 2006

A chloride is an important deteriorating factor which governs the durability of the reinforced-concrete structures under marine environments. Also, the main penetration mechanism of chloride ion into concrete is a diffusion phenomenon and numerous methods have been proposed to determine the diffusion coefficient of chloride ion quickly. In this study, electrically accelerated experiments were carried out in order to evaluate diffusion coefficient of the chloride ion into concrete. The methods were diffusion cell test method in which the voltage of 15V(DC) was applied. The type of cement is blended cement in which the admixtures of blast-furnace slag and fly ash were used. In conclusion, the diffusion coefficient of chloride ion is much affected according to mineral admixtures and the diffusion coefficient of ternary blended cement showed very low values. it is presumably said that this result is due to highly densified pore structures by the aid of slag substitution and pozzolanic activity of fly ash.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.577-580
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• 2003

Problem of repairing by boring is that it deteriorates stabelety and durability of structure by permeation of seawater from underneath after damage and repair of reinforcing rod regarding of spot. The purpose of this study is to improve the porblem by using the repair method of general boring to mend the of large mat basis. Direction of thes experiment is to apply the new repair material and the method to control the blazing fire factor caused by the crack from the foundation of large mat and also to estimate it's integrity. New method of construction is method of contruction that do speace scurity in vertical drilling and bottom useing water jet. New material used bantonite and rubberized asphalt. Test result existent repair method of construction large size mat basis perforation is difficult and reinforcing rod can be damaged coule there were a lot of problems with re-water leakage of crack repair region, but overcomes existent short coming by method that apply in this study.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.297-300
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• 2003

A chloride is an important deteriorating factor which governs the durability of the reinforced-concrete structures under marine environments. Also, the main penetration mechanism of chloride ion into concrete is a diffusion phenomenon. In this study, It is evaluated the diffusion coefficient of chloride ion in non-steady state by Fick's second law. Submergence method in salt water carried out in this experiment. Two types of cement which is different in mineral composition were used. In addition, the effect of mineral admixtures of blast-furnace slag and meta-kaolin was studied. In conclusion, the diffusion coefficient of chloride ion is much affected according to cement type and mineral admixtures, also, it is proved that meta-kaolin as well as blast-furnace slag is effective in preventing penetration of chloride ion.

• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.401-411
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• 2006

The major objective of this study is to investigate the dynamic behaviors of track due to the deterioration characteristics of ballast for servicing tracks by the field test. The durability of ballast plays an important role in the track behaviour. To estimate the deterioration characteristics of ballast, several tests have been carried out by several scholars. The deterioration characteristics of ballast is one of the most important factor in the dynamic behaviour of track and its life. In this paper abrasion/breakage characteristics of ballast is studied to predict the effect of physical ballast characteristics on ballast track. To reveal deterioration characteristics of ballast, the field test were carried out. The deterioration characteristics, studied in this paper, is applied to the dynamic behaviour of track in various conditions.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.591-596
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• 2005

The major objective of this study is to investigate the dynamic behaviors of track due to the deterioration characteristics of ballast for servicing tracks by the field test. The durability of ballast plays an important role in the track behaviour. To estimate the deterioration characteristics of ballast, several tests have been carried out by several shcolars. The deterioration characteristics of ballast is one of the most important factor in the dynamic behaviour of track and its life. In this paper abrasion/breakage characteristics of ballast is studied to predict the effect of physical ballast characteristics on ballast track. To reveal deterioration characteristics of ballast, the field test were carried out. The deterioration characteristics, studied in this paper, is applied to the dynamic behaviour of track in various conditions.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.557-560
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• 2003

Some well-known artificial weathering tests such as freezing-thawing, acid immersion, and salt crystallization are adopted to examine the change of rock properties during the processes of artificial weathering. Granites and other rock types of limestone, marble and basalt collected from different quarries in south Korea were sampled for this study. All tests were performed up to 30 cycles and physical properties were measured after experiencing every ten cycles of artificial weathering tests. During the tests, the variation trends of rock properties were too variable to draw generalized variation patterns but it can be concluded that weathering agents have different effect on rock properties depending on weathering circumstance and time. Even in short terms of salt crystallization tests, some rocks were severely deformed and then burst, and in the early stages of salt weathering, recrystallized salts filling pores and cracks in rocks could be a important factor affecting rock properties.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.18-23
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• 1996

Since at least three-quarters of the volume of concrete is occupied by aggregate, it is not surprising that its quality is considerable importance. Not only may the aggregate limit the strength of concrete, as weak aggregate cannot porduce strong concrete, but the properties of aggregate greatly affect the durability and sructural performance of concrete. But, it is ture that aggregate strength is usually not a factor in normal concrete strength because the aggregate particle is several times stronger than the matrix and the transition zone in concrete. This study is to consider the influence the strength of concrete according to the kinds of aggregate, such as crushed river rocks, curshed rocks, high strength recycled aggregate, low strength recycled aggregate at water cement ratio 0.25. It is possible to concern the important of the mechanical role of aggegate for the high strength concrete.

• Journal of the Korea Institute of Building Construction
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• v.5 no.2 s.16
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• pp.123-130
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• 2005

The purpose of this study is to present the optimum performance of hybrid waterproofing technology, which is including material and construction method. Recently, Hybrid waterproofing technology is developed little by little in KOREA. But there is not any other criterion of performance and evaluation of this technology. So, It is needed that appropriate performance items is are settled urgently. This paper were obtained by the SPSS analysis. In this study the safety factor are more important performance of building waterproofing materials than durability comfortability and productivity. And results of this analysis showed that (1) safety performance consists of Fatigue resistance, Crack Control performance deterioration Processing of tensile performance, Compressive Strength test (2) comfortability performance consists of watertightness, bond performance (3) persistency performance consists of abrasion resistance, tensile performance, flexural strength (4) productivity performance consists of dimension, unit space weight.