• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.641-650
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• 2010

The concrete cracking from the restrained stress caused by the shrinkage may play significant cause of deterioration of concrete structures by allowing the permeation of sulphate and chloride ions which in turn triggers corrosion of steel reinforcement. In particular, the cracking becomes more critical as water binder ratio (W/B) is reduced and concrete strength increases. Therefore, it needs to evaluate correctly the comprehensive shrinkage behavior of concrete with high strength: high-strength concrete (HSC), ultra-highstrength concrete (UHSC). The unrestrained shrinkage tests, however, cannot estimate the net shrinkage effectively which affects cracking after full development of strength and stiffness because it does not consider the degree of restraint, strength development, stress relaxation, and so on. Therefore, in this study, both free and restrained shrinkage tests with variables of W/B (W/B of 30, 25 and 16%) and admixtures (fly ash (FA) and granulated blast-furnace slag (BFS)) for HSC, very-high-strength concrete (VHSC) and UHSC were performed. The test results indicated that the autogenous shrinkage and total shrinkage at drying condition were reduced as W/B increased and FA, BFS were added, and the cracking behavior was suppressed as W/B increased and FA was added.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.7
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• pp.1054-1058
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• 2006

The purpose of this study was to use pig blood plasma transglutaminase (TGase) combined with thrombin and fibrinogen as a binder, which was applied to restructured meat, and to investigate its effect on the restructured meat quality. Pig meat was obtained 10 h post mortem from a traditional market was ground using a 10 mm aperture plate. A binder admixture was added (TGase:thrombin:fibrinogen mixed as 0.5:1:20 (v/v/v) to which was added 12% of its volume of 0.25 M calcium chloride) at 0, 5, 10, 15 and 20% of meat weight. Measurements included cooking loss, shrinkage rate, shear value, total plate count, pH value, TBA value, color difference, tension strength and sensory evaluation. The results showed that ground meat containing 20% w/w of binder admixture had higher cooking loss, shrinkage rate and shear value (p<0.05). Addition of different percentages of binder admixture did not affect total plate count, pH value, TBA value, and sensory evaluation of restructured meat (p>0.05). Tension strength was increased with increased level of binder admixture. Addition up to 15% binder admixture to restructured meat showed better scores of sensory texture, flavor and total acceptability (p<0.05).

• Journal of the Korea Concrete Institute
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• v.13 no.1
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• pp.30-37
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• 2001

Generally, polymer mortar made with unsaturated polyester(UP) resin has a high curing shrinkage. This is an inadequate as repair material and construction products that have been widely used for years recently. To overcome these problems, polymer researchers and engineers have used shrinkage-reducing additives, which are usually specific thermoplastic polymers. The objective of this study is to evaluate the effects of shrinkage-reducing additive on the curing shrinkage and strengths of UP mortar. UP mortars are prepared with expanded polystyrene(EPS) ratio in styrene monomer(SM), (EPS/PS, PS=EPS+SM), and the ratio of total polystyrene resin(PS) to UP resin, (PS/UP). And it is tested for viscosity of UP resin, slump-flow, working life, flexural and compressive strengths, and curing shrinkage tests. From the test results, viscosity of resin for UP mortar increases with increasing PS content. Curing shrinkage of UP mortar is considerably smaller than that of plain UP mortar, nevertheless, reduction in the strengths is not recognized according to adding PS resin. In this study, we can obtain the optimum mix proportions of UP mortar using PS resin which made of waste expanded polystyrene.

• Journal of the Korea Concrete Institute
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• v.25 no.6
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• pp.593-599
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• 2013

The unrestrained shrinkage strain of alkali-activated (AA) slag concrete was examined and compared with design equations specified in code provisions and empirical equations proposed by Yang et al. The main parameters investigated were the water-to-binder ratio (W/B), unit water content and fine aggregate-to-total aggregate ratio (S/a). Test results revealed that shrinkage strain of AA slag concrete is nearly proportional to the W/B ratio, whereas its time function is independent of the W/B ratio. The shrinkage strain of AA slag concrete increased significantly when the unit water content is above $185kg/m^3$, whereas it is marginally affected by the S/a ratio. The design equation of ACI 209 considerably overestimates the shrinkage behavior of AA slag concrete, whereas CEB-FIP equation tends to underestimate the shrinkage at the age more than 28 days. The empirical equation of Yang et al. is in better agreement with test results, showing that values of mean and standard deviation of error coefficients obtained from each specimen are 016 and 0.07, respectively.

• Computers and Concrete
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• v.19 no.1
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• pp.51-58
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• 2017

The paper presents the experimental investigations for studying the effect of ground granulated blast furnace slag (GGBFS) on the time-dependent deflection of reinforced concrete (RC) beams due to creep and shrinkage. The RC beams were reinforced with 2-10 mm bars at tension side and subjected to constant sustained two-point loading for the period of 150 days. The amount of cement replacement by GGBFS was varied from 0 to 60% with an increment of 20%. The total deflection was measured at different ages of up to 150 days under sustained loads. The experiments revealed that the time-dependent deflection of the reinforced concrete RC beams containing GGBFS was higher than that of plain concrete RC beams. At 150 days, the average creep and shrinkage deflection of RC beams containing 20%, 40% and 60% GGBFS was 1.25, 1.45 and 1.75 times higher than the plain concrete beams. A new model, which is an extension of authors' earlier model, is proposed to incorporate the effect of GGBFS content in predicting the long-term deflection of RC beams. Besides validating the new model with the current data with higher percentage of tension reinforcement, it was also used to predict the authors' earlier data containing lesser percentage of tension reinforcement with reasonable accuracy.

• Journal of the Korean Society of Hazard Mitigation
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• v.1 no.2 s.2
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• pp.93-101
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• 2001

The objective of this study is to derive a shrinkage correction formula that considers temperature effect and to develop a methodology for the improved prediction of the long-term behavior of the FCM bridges by considering seasonal temperature variations in-situ. Thereby, current formulation were performed by using the actual experimental shrinkage data including seasonal temperature variation. The investigation of the long-term behavior of the FCM bridge was performed on the construction site in order to decide applicability of the shrinkage formula Numerical results by the general method indicates inaccurate values of total strain when considering real strain, whereas the applied method demonstrates a good agreement in the resultant strain. In consequently, the applied method will improve the prediction of the long-term deformation of the FCM Bridges.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.180-181
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• 2017

This study aims to analyze the high strength mortar's fundamental properties and autogenous shrinkage properties by taking into consideration the result of the previous study in which it was found that ERBO(Biodiesel) exercises greatest effect on the expansion effect of mortar, and changing the time and rate of mixing the ERBO. A total of five levels were set as experimental variables: the three levels of the rate of ERBO, 0, 0.5, 1.0%, and the two levels of the time of mixing the ERBO: first, adding the ERBO with the mixing water and mixing it before, and second, mixing it after the mortar is completely mixed. It was found that the rate of length change decreased as the rate of ERBO increased, and the rate of length change was lower when the ERBO was mixed sooner.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.709-712
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• 2008

RC super tall buildings are planned and constructed recently in domestic area. Concrete is characterized by time dependant material such as creep and shrinkage. For this properties of concrete, differential shortening is one of the main issues on super tall buildings construction. This study includes material research, which is performing as a pre design stage to solve differential shortening on Lotte Super Tower Jamsil core structure(50, 60, & 70 MPa). The major part of this study is composed with comparison and analysis between experimental data and predicted data on total shrinkage and total compliance which were used on design stage. Four models, ACI209R Model, Ba${\check{z}}$ant-Baweja B3 Model, CEB MC99 Model, & GL2000 Model, were employed to predict them. It also tries to seek a proper model for high strength and high performance concrete in the case of no concrete test.

• Journal of the Korea Concrete Institute
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• v.16 no.3 s.81
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• pp.391-396
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• 2004

Plastic shrinkage crack occurs at the exposed surfaces of freshly placed concrete due to consolidation of the concrete mass and rapid evaporation of water from the surface. This so-called shrinkage crack is a major concern for concrete, especially for flat structures such as pavements, slabs for industrial factories and retaining walls. This study has been performed to obtain the plastic shrinkage and the permeability of hydrophilic poly vinyl alcohol(PVA) fiber reinforced mortar and concrete. Test results indicated that PVA fiber reinforced cement composite showed an ability to reduce the total crack area and the maximum crack width (as compared to plain and polypropylene fiber reinforced concrete). Also, according to the permeability test result, it was found that PVA fiber reinforced cement composite was more reducing than polypropylene fiber reinforced cement composite.

• Journal of Cadastre & Land InformatiX
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• v.52 no.2
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• pp.35-51
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• 2022

This study investigates how much building area among total building area concentrates on urban region in a local government region and then, I applies 'The Index of Building Concentration in Urban Area' for the first time in a study. The finding shows that Cities' Index is higher than counties', and also shows that a lower index is associated with a higher rate of older adult population, and is also associated with higher general budget expenditure by the local government based on the index of Building Concentration in Urban Area in Gyeongbuk Province. This study provides evidence that the Index of Building Concentration in Urban Area can be utilized in measuring shrinkage level, effectiveness of municipal finance, and in establishing shrinkage city/county planning by basic data.