• Geomechanics and Engineering
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• v.12 no.4
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• pp.561-577
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• 2017

Vast parts of the east of Tabriz city have been covered by Baghmisheh formation marls. These marls can be classified into three types based on their color as identified in yellow, green, and gray marls. Many high-rise buildings and other projects were founded and now is constructing on these marls. Baghmisheh formation marls are classified as stiff soil to very weak rock, therefore they undergo considerable consolidation settlement under foundation loads. This study presents the physical properties and consolidation behavior of these marls. According to the XRD tests, major clay minerals of marls are Illite, Kaolinite, Montmorillonite and Chloride. Uniaxial compressive strength are 100-250, 300-480 and 500-560 kPa for yellow, green and gray marls, respectively. Consolidation and creep behavior of Baghmisheh marls investigated by using of one dimensional consolidation apparatus under stress level up to 5 MPa. The results indicate that yellow marls have high compressibility, settlement and deformation modules. Green marls have an intermediate compressibility and settlement and while gray marls have low compressibility and settlement and from the foundation point of view have high stability. According to the creep test results, all types of marls have not been entered to progressive creep phase up to pressure 5 MPa.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.693-696
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• 2008

In order to assess time-dependent behaviors of the high-strength concrete that applied in actual FCM bridges with various curing environments, the shrinkages of air-dried, sealed, and moist 100${\times}$100${\times}$400 mm prism specimens were measured. And the compressive creep test of 3 and 28 days aged concrete in the tap water and 10% CaCl$_2$ solutions were carried out, then results were compared with traditional test results of air-dried and sealed specimens. Time-dependent behaviors of the concrete that according to curing circumstances between sealed and moist specimens show remarkable differences not only on the shrinkage but also on the creep. Hence there need some reconsiderations to the traditional creep test manners that predicting the creep and shrink age of actual concrete structures.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.171-177
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• 2000

It is essential to understand the creep behavior, which shows how long the characteristics of material maintains because press joined molding GMT-Sheet for recycle is usually used in the severe environment. In this study, we predict joining strength of GMT-Sheet for recycle, when lap length was changed. and we will investigate how compression ratio have an effect on creep behavior in press joined molding. The result of experiment of forming condition concerned with joining problem of GMT-Sheet is as followings joining efficiency. of GMT-Sheet, increases as lap joint length I, increases. Increase of compression ratio causes decrease o f joining efficiency after of GMT-Sheet joining. As the result of creep test, GMT-Sheet is easily damaged in high temperature range, because it is sensitive to the temperature

• Journal of Korean Association for Spatial Structures
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• v.10 no.3
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• pp.57-64
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• 2010

Uniaxial tensile tests of ETFE membrane are performed in this paper. Three kinds ETFE membrane with different thickness are used in the tests. The tensile strength, the tensile strain at break and the stress-strain curve are obtained from the tests. Futhermore, The cycle loading test of ETFE membrane is carried out through using different values of cycle stress. The residual strain, the relaxation of stress and the change of the elastic modulus of foil are investigated. In the creep test, three kinds of temperature (25, 40 and 60 $^{\circ}C$)and three kinds of stress(3,6and9 MPa) are set respectively and the creep time lasts 24 hours.

• Journal of Korean Association for Spatial Structures
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• v.11 no.3
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• pp.115-123
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• 2011

It is needed to investigate the material properties of ETFE foil under various temperatures because ETFE membrane foils have very thin depth and relatively high flexibility. In this paper, the material properties of ETFE membrane foil obtained from 3 testes under various temperatures are presented. First, the uniaxial test under four temperatures as -20$^{\circ}C$, 0$^{\circ}C$, +20$^{\circ}C$ and +40$^{\circ}C$ was performed. Each 5 specimen was tested and the yield stress, tensile strength and the Young's modulus of the foils are obtained. Second, the creep testes under three temperatures as 25$^{\circ}C$, 40$^{\circ}C$ and 60$^{\circ}C$, 3MP, 6MP and 9MP tension load was subjected to the specimen and the creep characteristics was investigated. Finally, the tear test under $5^{\circ}C$, $^0{\circ}C$ and $20^{\circ}C$ was performed. It is concluded that the shape of stress-strain curve or general behaviors are similar with that of normal temperatures but the mechanical characteristics of ETFE membrane foils were affected by the temperatures, obviously.

• Journal of the Korean Society of Safety
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• v.7 no.3
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• pp.99-107
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• 1992

Weld bonding can be applied as a combined method of spot welding and adhesive to have more advantages than those. Weld bonding has many merits that enlarge the fatigue strength of spot Welding and also improve the creep of adhesive. But it has not beer proved well in the various environmental conditions. In this study, weld bonding test for fatigue properties and tensile strength is presented under such various coditions as temperatures, humidity, and etc.

• Journal of the Korea Concrete Institute
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• v.26 no.3
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• pp.247-254
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• 2014

Strain properties of concrete member which acts as an important factor in the stability of the concrete structure in the event of fire, significantly affected the characteristics of the coarse aggregate, which accounts for most of the volume. For this reason, there are many studies on concrete using artificial lightweight aggregate which has smaller thermal expansion deformation than granite coarse aggregate. But the research is mostly limited on concrete using clay-based lightweight aggregate. Therefore, in this study, the high temperature compressive strength and elastic modulus, thermal strain and total strain, high temperature creep strain of concrete was evaluated. As a result, remaining rate of high-temperature strength of concrete using lightweight aggregate is higher than concrete with general aggregate and it is determined to be advantageous in terms of structural safety and ensuring high-temperature strength from the result of the total strain by loading and strain of thermal expansion. In addition, in the case of high-temperature creep, concrete shrinkage is increased by rising loading and temperature regardless of the type of aggregate, and concrete using lightweight aggregate shows bigger shrinkage than concrete with a granite-based aggregate. From this result, it is determined to require additional consideration on a high temperature creep strain in case of maintaining high temperature like as duration of a fire although concrete using light weight aggregate is an advantage in reducing the thermal expansion strain of the fire.

• Journal of the Korean Geosynthetics Society
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• v.2 no.2
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• pp.33-38
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• 2003

Polyester woven geotextiles to be bonded with nonwovens were manufactured for reinforcement and the allowable strength of these were obtained by the results of creep tests. Long-term design strength were calculated in consideration with factors of safety for design and construction and the long-term behaviors of geogrids were compared to those of composite woven geotextiles to examine the reinforcement function. From the experimental results, it was confirmed that these woven composite geotextiles could have the sufficient performance as an alternative geosynthetics instead of geogrids and the further study will be continue to confirm the possibility of woven composite geotextiles as the excellent reinforcing material.

• Nuclear Engineering and Technology
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• v.46 no.6
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• pp.857-862
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• 2014

Mechanical alloying under various gas atmospheres such as Ar, an Ar-$H_2$ mixture, and He gases were carried out, and its effects on the powder properties, microstructure and mechanical properties of ODS ferritic steels were investigated. Hot isostatic pressing and hot rolling processes were employed to consolidate the ODS steel plates. While the mechanical alloyed powder in He had a high oxygen concentration, a milling in Ar showed fine particle diameters with comparably low oxygen concentration. The microstructural observation revealed that low oxygen concentration contributed to the formation of fine grains and homogeneous oxide particle distribution by the Y-Ti-O complex oxides. A milling in Ar was sufficient to lower the oxygen concentration, and this led a high tensile strength and fracture elongation at a high temperature. It is concluded that the mechanical alloying atmosphere affects oxygen concentration as well as powder particle properties. This leads to a homogeneous grain and oxide particle distribution with excellent creep strength at high temperature.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.689-692
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• 2008

The purpose of this study was to analyze mechanical properties through an experiment of concrete that reinforced PET fiber, blast furnace slag and Hwangtoh. As admixture that is substitute material of cement for environmental concrete development In order to measure compressive strength, the experiment has executed to concrete, Hwangtoh concrete and a mixture specimen of Hwangtoh and PET reinforcement fiber. Also, creep and drying shrinkage experiment have executed to analyze long-term quality of specimens. Test results, compressive strength by age was not much of difference as a substitute, however, compressive strength of HTC specimen was the strongest of the three specimens. In the case of creep and drying shrinkage, long-term quality of HTC specimen was distinguished.