• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.467-472
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• 2000

It is known that chloride ion in concrete destroys the passive film of reinforcement inside concrete and accelerates corrosion which is the most influencing factor to durability of concrete structures. In this thesis, a chloride ion diffusion model for blast furnace slag(BFS) concrete, which has better resistance to both damage due to salt and chloride ion penetration than ordinary portland cement concrete, is proposed by modifying existing model of normal concrete. Proposed model is verified by comparing diffusion analysis results with both results by indoor chloride penetration test for specimens and field test results for actual RC bridge pier. Also, the optimum resistance condition to chloride penetration is obtained according to degrees of fineness and replacement ratios of BFS concrete. As a result, resistance to chloride ion penetration for BFS concrete is more affected by replacement ratio than degree of fineness.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.401-404
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• 2008

균열은 콘크리트에 염소이온과 같은 유해한 물질의 침투경로가 되어 내구성에 심각한 열화를 야기한다. 따라서 고내구성 재료를 사용한 콘크리트 휨부재에서의 균열 발생에 따른 염소이온 침투특성을 검토하고자 하였다. 이를 위해, 고내구성 재료를 적용한 보에 하중을 가하여 휨균열을 도입시키고, 촉진 염화물 침투실험(RCPT)과 장기 염화물 침투실험을 실시하여 염화물 침투 특성을 파악하였다. 실험결과에 따르면, 고내구성 재료를 적용한 부재는 균열이 발생하여도 일반 콘크리트 부재에 비해 높은 염화물 침투 저항성을 보였다. 특히 고로슬래그 미분말을 적용한 경우, 균열 부재의 장기 염화물 침투 실험에서 탁월한 염화물 침투 저항성을 보였다.

• 한국구조물진단유지관리공학회 논문집
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• 제22권6호
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• pp.16-23
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• 2018

본 연구에서는 표면 침투 및 코팅형 흡수방지재인 Polydimethylsiloxane(PDMS)을 고인성 섬유복합체(ECC)에 적용하여 적용성, 강도 평가 및 염화물이온 침투 저항성능에 대한 연구를 수행하였다. PDMS 적용 방법에 따른 침투깊이를 분석한 결과 모든 방법에서 KS F 4930 의 기준을 만족하는 것을 확인하였다. 적용 방법 중, 침지 방법이 가장 우수한 침투깊이를 보였으나 현장적용성을 고려할 경우 스프레이 방법이 적용 가능한 것으로 확인되었다. ECC 배합에 따른 PDMS 침투깊이 실험 결과 배합강도가 감소할수록 침투깊이는 최대 70% 이상 증가하는 경향을 나타났다. 압축강도 시험 결과에서는 PDMS 침투 깊이가 큰 M4-A, M4-B 시험체의 압축강도는 PDMS를 적용하지 않은 M4 시험체와 비교하여 9.6%, 8.0% 압축강도가 감소하였다. 또한, 침투깊이가 작은 M1-A와 M1-B 시험체의 압축강도는 M1 시험체와 비교하여 4%, 2.2% 감소하여 PDMS 침투깊이가 클수록 강도감소율이 증가하였다. 염소이온침투 저항성능 평가 시험결과, PDMS의 침투깊이가 클수록 염소이온 침투 저항성능이 향상되는 것을 확인하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.433-436
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• 1999

Long-term durability of the reinforced concrete structures exposed to marine environment deteriorates seriously by the attack of the chloride ion from see water results in corrosion of steel reinforcement in concrete. Their coating effect is aluminum oxide-isocyanate-based coating material, resistance of chloride penetration, carbonation and freezing and thawing resistance were compared to acryl-based coating material and sealer type o waterproofing material. Aluminum oxide-isocyante-based and acryl-based coating material show higher resistance to chloride penetration and carbonation than the sealer type do waterproofing material and aluminum oxide-isocyanate-based coating resist about 99% of chloride penetration. Resultants to the accelerated test for freezing and thawing, coating concrete show higher resistance than non-coating concrete, respectively.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.165-166
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• 2020

The climate on the Korean Peninsula has been warmed recently, abnormal weather conditions such as heat waves, cold waves, and tropical nights have been detected frequently. Precisely, the number of days with cold waves in the winter has increased, and rapid changes of temperature in the morning and afternoon have occurred frequently in the 2000s. Due to the previous phenomenons, this research is focused on evaluating the concrete's Chloride Penetration Resistance and Durability, and the difference of the resistance according to the W/C.

• Geomechanics and Engineering
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• 제13권3호
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• pp.475-488
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• 2017

Geotechnical data contributes substantially to the cost of engineering projects due to increasing cost of site investigations. Existing information in the form of soil maps can save considerable time and expenses while deciding the scope and extent of site exploration for a proposed project site. This paper presents spatial interpolation of data obtained from soil investigation reports of different construction sites and development of soil maps for geotechnical characterization of Multan area using ArcGIS. The subsurface conditions of the study area have been examined in terms of soil type and standard penetration resistance. The Inverse Distance Weighting method in the Spatial Analyst extension of ArcMap10 has been employed to develop zonation maps at different depths of the study area. Each depth level has been interpolated as a surface to create zonation maps for soil type and standard penetration resistance. Correlations have been presented based on linear regression of standard penetration resistance values with depth for quick estimation of strength and stiffness of soil during preliminary planning and design stage of a proposed project in the study area. Such information helps engineers to use data derived from nearby sites or sites of similar subsoils subjected to similar geological process to build a preliminary ground model for a new site. Moreover, reliable information on geometry and engineering properties of underground layers would make projects safer and economical.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.820-824
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• 1997

In order to investigate the effect of surface treatment(Anodizing) and rolling in Al 5083-H131 alloy, ballistic testing was conducted. Ballistic resistance of these materials. was measured by protection ballistic limit(V$_{50}$), a statical velocity with 50% probability for incomplete penetration. Fracture behaviors and ballistic tolerance, described by penetration modes, are observed respectfully, resulting from V$_{50}$ test and Projectile Through Plates(PTP) test at velocities greater than V$_{50}$. PTP tests were conducted with 0$^{\circ}$obliquity at room temperature were also conducted with projectiles that were able to achieve near or complete penetration during PTP tests. Resistance to penetration, and penetration modes of Al 5052-H34 alloy, compared to those of Al 5083-H131 alloy.alloy.

• The Plant Pathology Journal
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• 제26권2호
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• pp.149-153
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• 2010

Biological and structural mechanisms of the nematode disease development in chili pepper caused by the root-knot nematode, Meloidogyne incognita, were investigated. Out of 39 chili pepper cultivars/lines tested, six were found resistant, while 33 were susceptible to M. incognita, of which a susceptible cultivar Chilseongcho and three resistant cultivar/lines CM334, 02G132 and 03G53 with different resistance degrees were selected for microscopic studies on the disease development. Gall formation was greatly reduced in the resistant cultivars/lines. Nematode penetration occurred both in the susceptible and resistant chili pepper roots; however, the penetration rates were significantly lowered in the three resistant peppers compared to the susceptible pepper cv. Chilseongcho. In the susceptible pepper, giant cells were extensively formed with no discernible necrosis around the nematode feeding sites. In the highly resistant pepper cultivar CM334, no giant cell was formed, but extensive necrosis formation was observed around the penetrating nematodes. In the other two resistant pepper lines (02G132 and 03G53), both giant cells and prominent necroses were formed, and the necrotic responses appeared to inhibit the further development of giant cells or accelerate their early degeneration. Although the nematode penetration was retarded significantly in the resistant cultivar/lines, all of the above results suggest that the disease resistance of pepper may be related to post-infectional defense mechanisms (nematode growth and development) more than pre-infectional ones (penetration and establishment). Variations in structural modifications in the resistant cultivar/lines may reflect their genetic differences related to the nematode resistance.

• Journal of Biosystems Engineering
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• 제34권6호
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• pp.397-403
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• 2009

This study was carried out to investigate the present status of subsoil compaction, and subsoil compaction management in orchard as a basic study for developing a self-propelled explosive subsoiler. Subsoil compaction was evaluated using the soil penetration resistance. Soil cone index was measured using the DIK 5520 type cone penetrometer in several fruit farms such as apple, pear, peach and grapes during growing seasons of these fruit in Jecheon, Gamgok, Choongju, Cheonan and Hwasung areas. Most of the subsoil managing machinery were either explosive type or digging type attached to the tractor or power tiller and turning radius of this machine was more than 3-5 m. Many of the farmers wanted to use the subsoiler which can put lime into soil and rupture soil at the same time. For most of the orchard fields, soil penetration resistance in vehicle traffic area was increased quickly and reached about 1.0 MPa in 5 cm soil depth. As the soil depth increased to 15-20 cm, cone penetration resistance reached about 2.0-2.5 MPa which restricted root growth seriously. Thus it was concluded that one of the main reason for increasing the soil compaction in orchard fields is agricultural vehicle traffic. In the vicinity of fruit trees, compaction is not so serious compared to that of the vehicle traffic area, but as the soil depth increased to 20-25 cm, in most of the orchard fields soil penetration resistance reached about 2.0-2.5 MPa which is the root growth-limiting value. Considering the rooting depth of fruit trees which ranged 30-60 cm for apple, pear and peach, and 20-30 cm for grape, it is necessary to loosen the subosoil and improve the subsoil conditions using subsoiler.

• 한국구조물진단유지관리공학회 논문집
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• 제15권2호
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• pp.79-87
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• 2011

본 연구에서는 초기 균열을 도입한 철근콘크리트 부재에 대한 침지 염화물 침투 실험을 수행하였다. 염화물 확산 특성과 임계 균열폭을 비교하였으며, 콘크리트 자기복원 특성을 검토하였다. 실험결과에 따르면, 표면 균열폭이 증가할수록 염화물 침투저항성이 크게 감소하였으며, 광물질 혼화재를 사용할 경우, 비균열 부재의 염화물 침투저항성은 크게 개선되었지만, 고로슬래그 및 플라이애쉬 혼화재를 사용할 경우에 균열이 발생하게 되면 도리어 염화물 침투저항성은 보통 콘크리트에 비해 크게 저하하였다. 임계 균열폭은 침지 염화물 침투 실험 결과 평균 $29{\mu}m$으로 측정되었다. 자기복원 현상에 의해 $4{\sim}15{\mu}m$ 범위의 균열이 복원되었다. 그러나 콘크리트 자기복원 현상에 의해 시각적으로 복원된 부분의 염화물 침투 저항성은 완전히 회복되지 않았다.