Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korea Concrete Institute
Journal Basic Information
Journal DOI :
Korea Concrete Institute
Editor in Chief :
Volume & Issues
Volume 22, Issue 6 - Dec 2010
Volume 22, Issue 5 - Oct 2010
Volume 22, Issue 4 - Aug 2010
Volume 22, Issue 3 - Jun 2010
Volume 22, Issue 2 - Apr 2010
Volume 22, Issue 1 - Feb 2010
Selecting the target year
Development of Underwater Adhesive, Epoxy, and FRP Composite for Repair and Strengthening of Underwater Structure
Kim, Sung-Bae ; Yi, Na-Hyun ; Nam, Jin-Won ; Byun, Keun-Joo ; Kim, Jang-Ho Jay ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 149~158
DOI : 10.4334/JKCI.2010.22.2.149
Recently, numerous construction techniques for repairing and strengthening methods for above ground or air exposed concrete structure have been developed. However repairing and strengthening methods for underwater structural members under continuous loading, such as piers and steel piles need the further development. Therefore, this study develops an aqua epoxy, which can be used for repairing and strengthening of structural members located underwater. Moreover, using the epoxy material and strengthening fibers, a fiber reinforced composite sheet called Aqua Advanced FRP (AAF) for underwater usage is developed. To verify and to obtain properties of the material and the performance of AAF, several tests such as pull-off strength test, bond shear strength test, and chemical resistance test, were carried out. The results showed that the developed aqua epoxy does not easily dissolve in wet conditions and does not create any residual particle during hardening. In spite of underwater conditions, it showed the superior workability, because of the high viscosity over 30,000 cps and adhesion capacity over 2 MPa, which are nearly equivalent to those used in dry conditions. In case of the chemical resistance test, the developed aqua epoxy and composite showed the weight change of about 0.5~1.0%, which verifies the superior chemical resistance.
Multi-physics Model of Moisture Related Shrinkage on Lightweight and Normal Concrete
Lee, Chang-Soo ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 159~169
DOI : 10.4334/JKCI.2010.22.2.159
A multiphysics model analysis including moisture transport, heat transfer and solid mechanics and experiments on the normal and light weight concrete were carried out in order to study the effect of preabsorbed water in the light weight aggregates on the drying and shrinkage characteristics of concrete. Consequently, with fixed water-cement ratio, loss of water content of normal and light weight concrete were compared and the results showed that the lightweight concrete lost less moist than the normal concrete in early age and long term which was by moist supply effect. Accordingly, shrinkage strain size and distribution of lightweight concrete were decreased, and shrinkage reducing effect was efficient in early age with water cement ratio 0.3 and in both early age, and long term with water cement ratio 0.5. The comparison of analysis results and exaperimental results indicate that characteristic values of moisture transport and the relation humidity and shrinkage strain from this study are resonable for application for other differential shrinkage analysis in lightweight concrete.
Development of PBD Method for Concrete Mix Proportion Design Using Bayesian Probabilistic Method
Kim, Jang-Ho Jay ; Phan, Duc-Hung ; Lee, Keun-Sung ; Yi, Na-Hyun ; Kim, Sung-Bae ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 171~177
DOI : 10.4334/JKCI.2010.22.2.171
Recently, Performance Based Design (PBD) method has been studied as a next generation structural design method, which enables a designed structure to satisfy the required performance during its service life. One method of deciding whether the required performance has been satisfied is Bayesian method, which has been commonly used in seismic analysis. Generally, it is presented as a conditional probability of exceeding some limit state (i.e., collapse) for a given ground motion. In PBD of concrete mixture design, the same methodology can be applied to assess concrete material performance based on some conditional parameters (i.e. strength, workability, carbonation, etc). In this paper, a detailed explanation of the procedure of drawing satisfaction curve by using Bayesian method based on various material parameters is shown. Also, a discussion of using the developed satisfaction curves for PBD for concrete mixture design is presented.
An Effect of Steel Corrosion on Bond Stress-slip Relationship under Repeated Loading
Kim, Chul-Min ; Park, Jong-Bum ; Chang, Sung-Pil ; Kim, Jee-Sang ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 179~186
DOI : 10.4334/JKCI.2010.22.2.179
The bond between steel and concrete in reinforced concrete members is essential to resist external load, but the bond mechanism in reinforced concrete beams deteriorated by steel corrosion has not been clearly known yet. Most existing researches have dealt with the bond behavior of corroded steel under monotonic loading, but scarce are researches dealing with bond behavior of corroded steel under repeated loading. This study includes the experimental investigation on the bond behavior with respect to the various degrees of steel corrosion under repeated loading. According to the test results, the bond strength of corroded steel under monotonic loading increases as the rate of steel corrosion increases unless the splitting crack occurs. The slip versus number of load cycles relation was found to be approximately linear in double logarithmic scale, not only in specimens without steel corrosion but also in specimens with steel corrosion. The test results also show that the steel corrosion does not negatively affect the bond strength of corroded steel after repeated loading unless the splitting crack occurs. But the fatigue life decreases sharply after splitting crack occurs. This research will be helpful for the realistic durability design and condition assessment of reinforced concrete structures.
Longitudinal Reinforcement Ratio for Performance-based Design of Reinforced Concrete Columns
Kim, Chang-Soo ; Park, Hong-Gun ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 187~197
DOI : 10.4334/JKCI.2010.22.2.187
The longitudinal reinforcement ratio for the performance-based design of columns was studied. Unlike the existing design codes using uniform minimum reinforcement ratio and effective stiffness for all columns, the longitudinal reinforcement ratio of columns was defined as the function of various design parameters. To evaluate the minimum reinforcement ratio, two conditions were considered: 1) prevention of passive yielding of compression re-bars due to the creep and shrinkage of concrete under sustained service loads; and 2) ultimate flexural strength greater than the cracking moment capacity to maintain the ductility of columns for earthquake design. In addition, the effective flexural stiffness of columns for structural analysis was determined according to the longitudinal reinforcement ratio. The design method addressing the three criteria was proposed. The proposed method was applied to a design example.
Failure Behavior of FRP RC Beams without Shear Reinforcements
Lee, Jae-Hoon ; Son, Hyun-A ; Shin, Sung-Jin ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 199~208
DOI : 10.4334/JKCI.2010.22.2.199
In order to substitute FRP bar for steel bar in new structures, it is necessary to establish a reliable design code. But relatively little research has been conducted on the material in Korea. So, a total of 22 beam specimens (18 GFRP reinforced concrete and 4 conventional steel reinforced concrete) were constructed and tested. In the first phase of the experiment, it was carried out to observe flexural behavior, and collect deflection and crack data. In order to eliminate of the uncertainty by the shear reinforcements and induce flexural failure mode, any stirrup were not used and only shear span-depth ratio were adjusted. However, almost beams were broken by shear and the ACI 440.1R, CSA S806, which were used to design test beams, showed considerable deviation between prediction and test results of shear strengths. Therefore in the second phase of the study, shear failure modes and behavior were observed. A standard specimen had dimensions of 3,300 mm long
800 mm wide
200 mm effective depth. Clear span and shear span were 2,800 mm, 1,200 mm respectively. Control shear span-depth ratio was 6.0. Four-point bending test over simple support was conducted. Variables of the specimens were concrete compressive strength, type and elastic modulus of reinforcement, shear span-depth ratio, effective reinforcement ratio, the effect of bundle placing method and cover thickness.
The Prediction Model of Carbonation Process by CO
Diffusion Using the Air Permeability Coefficient for Concrete
Kang, Suk-Pyo ; Kim, Young-Sun ; Song, Ha-Won ; Kim, Gyu-Yong ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 209~217
DOI : 10.4334/JKCI.2010.22.2.209
Recently, some mathematical models for the prediction on progress of carbonation of concrete were reported. These models take account for
diffusion and chemical reaction between
. Based on the assumption that
diffuses in the carbonation zone and reacts with
at the outer face of carbonation zone and non-carbonation zone. In this study, a mathematical model to predict the progress of carbonation of concrete has been established based on the reducing concentration of
in the carbonation progress zone, where
coexist. Also, the prediction model of carbonation progress rate of concrete using the air permeability coefficient regarding to
diffusion is developed. As a result of this study, an expression, the model equation is obtained for the prediction of carbonation based on the time and interaction velocity between
dependent air permeability coefficient. The prediction by the model satisfied the experimental data of the accelerated carbonation for painted concrete. Consequently, the model can predict the rate of carbonation and the potential service life of concrete structure exposed to atmosphere.
Influence of Mineral Admixtures on the Resistance to Sulfuric Acid and Sulfate Attack in Concrete
Bae, Su-Ho ; Park, Jae-Im ; Lee, Kwang-Myong ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 219~228
DOI : 10.4334/JKCI.2010.22.2.219
It has been well known that concrete structures exposed to acid and sulfate environments such as sewer, sewage and wastewater, soil, groundwater, and seawater etc. show significant decrease in their durability due to chemical attack. Such deleterious acid and sulfate attacks lead to expansion and cracking in concrete, and thus, eventually result in damage to concrete matrix by forming expansive hydration products due to the reaction between portland cement hydration products and acid and sulfate ions. Objectives of this experimental research are to investigate the effect of mineral admixtures on the resistance to acid and sulfate attack in concrete and to suggest high-resistance concrete mix against acid and sulfate attack. For this purpose, concretes specimens with three types of cement (ordinary portland cement (OPC), binary blended cement (BBC), and ternary blended cement (TBC) composed of different types and proportions of admixtures) were prepared at water-biner ratios of 32% and 43%. The concrete specimens were immersed in fresh water, 5% sulfuric acid, 10% sodium sulfate, and 10% magnesium sulfate solutions for 28, 56, 91, 182, and 365 days, respectively. To evaluate the resistance to acid and sulfate for concrete specimens, visual appearance changes were observed and compressive strength ratios and mass change ratios were measured. It was observed from the test results that the resistance against sulfuric acid and sodium sulfate solutions of the concretes containing mineral admixtures were much better than that of OPC concrete, but in the case of magnesium sulfate solution the concretes containing mineral admixtures was less resistant than OPC concrete due to formation of magnesium silicate hydrate (M-S-H) which is non-cementitious.
Fire Resistance Performance of High Strength Concrete Columns with Fireproof Gypsum Board
Youm, Kwang-Soo ; Jeon, Hyun-Gyu ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 229~235
DOI : 10.4334/JKCI.2010.22.2.229
In this study, fire resistance performance of high strength concrete specimen with fireproof gypsum board was investigated for possible use in upgrading fire-resistant performance of the existing building and repair of fire damaged structures. Fire test of eight identical high strength concrete columns were carried out for 180 minutes in accordance with ISO-834. The temperature distributions in longitudinal reinforcement and concrete temperature at various depths were recorded. The fireproof performance of gypsum board and explosive spalling of concrete were observed. The specimens with 15 mm thick twoply fireproof gypsum board spalled after gypsum board crumbled regardless of fastening methods. However, when the thickness of fireproof gypsum board was more than 30 mm, it was possible to prevent the explosive spalling and control the rebar temperature. Although the effect of cover thickness could not be compared because the explosive spalling occurred, there seemed to be no difference in insulation efficiency.
Evaluation of Strength and Stiffness Gain of Concrete at Early-ages
Hong, Geon-Ho ; Park, Hong-Gun ; Eum, Tae-Sun ; Mihn, Joon-Soo ; Kim, Yong-Nam ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 237~245
DOI : 10.4334/JKCI.2010.22.2.237
Recently, deflection of the slab during construction periods becoming one of the important issues because of increasing the large-span structures. Early removing the form and support of the slab to achieve the rapid construction cause falling-off in quality of the structures. To reduce these deterioration and make rapid construction, construction of strength and stiffness gain model is needed by the research about the early-age concrete properties. Previous research results indicated that concrete model in existing design codes could not provide the mechanical properties of early age concrete. This paper carried out the concrete compressive strength tests on the curing age at early age stage. Evaluation of the accuracy of compressive strength and modulus of elasticity gain formula in existing various design codes was performed based on this test results, and new design model was proposed. This new model will be useful to develop the new rapid construction methods or prevent the deterioration of the deflection at construction periods. Material tests were performed at 1, 3, 7, 14, 28 curing days, total 159 cylinder style specimens were tested. Based on analyzing the test results, the relationship between compressive strength and modulus of elasticity at early age was proposed.
Load Resistance Mechanism and Behavior Characteristics of MRS Continuous Joints
Oh, Young-Hun ; Moon, Jeong-Ho ; Im, Ju-Hyeuk ; Choi, Dong-Sup ; Lee, Kang-Chul ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 247~254
DOI : 10.4334/JKCI.2010.22.2.247
The purpose of study is to investigate the load resistance mechanism of MRS continuous joint designed with different details. Six full-scale specimens, which could simulate the negative moment region of the 8 m long MRS system, were prepared to evaluate the structural performance of the continuous joint. According to the experimental results, all specimens which include the specimen with dapped ends designed by loads at the construction stage were failed in a flexural manner and showed the load carrying capacity over the nominal flexural strength. Therefore it is recommended that the dapped ends for MRS continuous joints be designed for the loads of the construction stage. And the shear key, which was installed on the top of rib for MRS slab, helps the enhancement of strength and especially deformation capacity.
A Study on Chloride Diffusion in Concrete Containing Lightweight Aggregate Using Crushed Stone-powder
Lee, Dae-Hyuk ; Yoon, Sang-Chen ; Jeong, Yong ; Shin, Jae-Kyung ; Jee, Nam-Yong ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 255~262
DOI : 10.4334/JKCI.2010.22.2.255
The purpose of this study is to provide preliminary data on chloride diffusion of lightweight aggregate concrete containing crushed stone-powder. Accordingly, the study performed experiments using concrete aggregates of Crushed Aggregate (CG), Single-sized Lightweight Aggregate (SLG), Continuous Graded Lightweight Aggregate (CLG), and using water-binder ratio of 0.4, 0.5, 0.6, and using binder of FA and BFS. The chloride diffusion coefficient is calculated according to the NT BUILD 492. Diffusion coefficient of SLG and CLG were higher than that of CG concrete, but the difference was not significant. Also, chloride diffusion coefficient data indicated that it was highly affected by water-binder ratio, and it decreased with the decrease in waterbinder ratio. The admixture substitution of FA15% was effective in decreasing the diffusion coefficient only with water-binder ratio of 0.4 while admixture substitution of FA10+BFS20% was effective with all levels of water-binder ratio. The result of study shows lightweight aggregate concrete containing crushed stone-powder has slightly higher chloride diffusion coefficient than CG concrete, but the difference is not significant such that it can be overcome by adjusting water-binder ratio and admixture substitution. In addition, the data indicate the chloride diffusion coefficient of lightweight aggregate concrete can be estimated from the strength of lightweight aggregate.
Low Cycle Fatigue Behavior of Longitudinal Reinforcement
Lee, Jae-Hoon ; Ko, Seong-Hyun ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 263~271
DOI : 10.4334/JKCI.2010.22.2.263
The purposes of this study is to verify the fracture characteristic of steel which is manufactured in Korea, subjected to cyclic loading. This investigation deals with the low cycle fatigue behavior of longitudinal reinforcement in reinforced concrete bridge substructure (piles and columns of piers). Eighty-one specimens of longitudinal reinforcement were tested under axial strain controlled reversed cyclic tests with strain amplitudes. The selected test variables are ratio of tension strain to compression strain, yield stress of longitudinal reinforcement, ratio of diameter of longitudinal steel to clear length of longitudinal steel, size of longitudinal steel and strain amplitudes. Low cycle fatigue behavior and low-cycle fatigue life are investigated and discussed in this paper.
Low Cycle Fatigue Model for Longitudinal Reinforcement
Ko, Seong-Hyun ; Lee, Jae-Hoon ;
Journal of the Korea Concrete Institute, volume 22, issue 2, 2010, Pages 273~282
DOI : 10.4334/JKCI.2010.22.2.273
The purposes of this study are to verify the existing model and to propose a rational model for the fracture characteristic of reinforcing steel which is manufactured in Korea being subjected to cyclic loading. This investigation deals with modeling of the low-cycle fatigue behavior for longitudinal reinforcement steel of reinforced concrete bridge substructure (piles and columns of piers). The proposed low-cycle model of longitudinal steel is modeled based on 81 experimental data. The non-linear analysis program was developed using the proposed low-cycle model. The non-linear analysis are applied to the 6 circular bridge column test results and the accuracy of proposed model is discussed.