• Title/Summary/Keyword: penetration resistance

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A Study on the Mock-up Test of Waterproofing/Root Penetration Resistance Technology for the Application to an Eco-bridge (생태교량 적용을 위한 방수·방근공법의 Mock-up 시험 연구)

  • Seon, Yun-Suk;Choi, Su-Young;Kim, Meong-Ji;Choi, Sung-Min;Oh, Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.230-231
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    • 2014
  • This study is concerned with the root penetration resistance competence and constructability of a waterproofing and root penetration resistance layer of an eco-bridge which is applied with various types of seeding. For the review of root penetration resistance competence, the competence was tested using herbs, woody plants, and tall trees. As a result, there was no tear of or damage to the waterproofing and root penetration resistance layer as well as the sweeping-down phenomenon of a waterproofing and root penetration resistance layer by soil. Also, the effect of the root growth of herbs, woody plants, and tall trees on the root penetration resistance system was confirmed.

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Ballistic Resistance of an Armor Ceramic Structure against a Shaped Charge Jet As a Function of Penetration Depth

  • Hyunho Shin;Lee, Chang-Hyun;Wan Sung
    • The Korean Journal of Ceramics
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    • v.5 no.3
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    • pp.270-277
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    • 1999
  • The ballistic capability of an alumina-rich oxide armor ceramic against a shaped jet was characterized as a function of penetration depth in a layered target structure. The penetration resistance of the ceramic, based upon the determination of penetration velocity, was not equally realized throughout the depth of penetration. It was abnormally low at an early stage of penetration, followed by a sudden increase to reach ~16GPa thereafter. There was no apparent change in such a profile with respect to the lateral size of the specimen. Based upon 2-D flash x-ray radiography and 3-D Hull code simulation, the feasibility of forming a pressure-induced predamnaged zone in front of the jet tip was speculated to foster an increased penetration velocity in the initial stage penetration, resulting in the diminished penetration resistance. The disappearance of such a predamaged zone with penetration was interpreted to restore the resistance of the ceramic in the later penetration stage.

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Applicability of Mini-Cone Penetration Test Used in a Soil Box

  • Sugeun Jeong;Minseo Moon;Daehyeon Kim
    • Journal of the Korean Geosynthetics Society
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    • v.22 no.4
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    • pp.83-92
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    • 2023
  • In this study, we conducted verification of key influencing factors during cone penetration testing using the developed Mini Cone Penetration Tester (Mini-CPT), and compared the experimental results with empirical formulas to validate the equipment. The Mini-CPT was designed to measure cone penetration resistance through a Strain Gauge, and the resistance values were calibrated using a Load Cell. Moreover, the influencing factors were verified using a model ground constituted in a soil box. The primary influencing factors examined were the boundary effect of the soil box, the distance between cone penetration points, and the cone penetration speed. For the verification of these factors, the experiment was conducted with the model ground having a relative density of 63.76% in the soil box. It was observed that the sidewall effect was considerably significant, and the cone penetration resistance measured at subsequent penetration points was higher due to the influence between penetration points. However, within the speed range considered, the effect of penetration speed was almost negligible. The measured cone penetration resistance was compared with predicted values obtained from literature research, and the results were found to be similar. It is anticipated that using the developed Mini-CPT for constructing model grounds in the laboratory will lead to more accurate geotechnical property data.

Investigation of Spudcan Penetration Resistance in Layered Soil Deposits

  • Jan, Muhammad Asad;Nizamani, Zubair Ahmed;Park, Duhee
    • Journal of the Korean GEO-environmental Society
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    • v.22 no.1
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    • pp.13-20
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    • 2021
  • A suite of 3D large deformation finite element (FE) analyses was performed to investigate the load transfer mechanism and penetration resistance of spudcan foundations in heterogeneous soil profile consisting of sand and clay. The Elasto-Plastic models following Mohr-Coulomb and Tresca failure criteria were adopted for sand and clay, respectively. The accuracy of the numerical model was validated against centrifuge test measurements. The dense sand behavior with dilation is modeled using the non-associated flow rule. An investigation study consisting of key parameters, which includes variation in soil stratigraphy (sand-clay, sand-clay-sand), strength parameters of sand and clay (��' and su) and normalized height ratio of the sand layer (Hs/D) was conducted to assess the penetration behavior of spudcan. Based on calculated outputs, it was demonstrated that these parameters have a significant influence on the penetration resistance of spudcan. The calculated penetration resistance profiles are compared with the published (sand overlying clay) analytical model. It is confirmed that for the case of two-layer soil, the available theoretical model provides an accurate estimate of peak penetration resistance (qpeak). In the case of three-layer soil, the presence of a third stiff layer affects the penetration resistance profile due to the squeezing of the soil.

The Effect of Mineral Admixtures' Type on the Chloride Penetration Resistance of Concrete (콘크리트의 염화물 침투저항성에 미치는 무기질 혼화재 종류의 영향)

  • Kim, Young-Jin;Kim, Dong-Seok;Yu, Jae-Kang
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.802-805
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    • 2004
  • This study was performed to investigate the effect of mineral admixture' type and replacement ratios on the chloride penetration resistance of concrete which was immersed in the artificial chloride solution. The chloride penetration resistance was evaluated by penetration depth and chloride diffusion coefficient. As a result, all of the mineral admixtures were effective on the chloride penetration resistance of concrete compared to ordinary portland cement only.

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An Experimental Study on the Salt Damage Resistance of High Durable Concrete (고내구성콘크리트의 염해저항성에 관한 실험적 연구)

  • Yoon, Jai-Hwan;Jaung, Jae-Dong
    • Journal of the Korea Institute of Building Construction
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    • v.3 no.3
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    • pp.73-81
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    • 2003
  • In this paper, salt damage resistance of high durable concrete was tested. High durable concrete was made by using low water cement ratio, chemical admixture called super-durable admixture and mineral admixtures such as fly-ash, ground granulated blast-furnace slag, silica fume. Two kinds of salt damage resistance test were carried out. One method is chloride ion penetration test(ASTM C1202), and the other one is depth of chloride penetration test in saline solution. Test results were as followers: 1) The depth of chloride ion penetration increased exponentially as water cement ratio was increased and time passed. 2) Super-durable admixture had little effect on the improvement of salt damage resistance of concrete. 3) Silica fume and ground granulated blast-furnace slag were effective on salt damage resistance because of pozzolanic reaction, but fly-ash had a little effect.

Evaluation of Chloride Ion Penetration Resistance of Coal Gasification Slag Replaced Concrete (석탄가스화 용융 슬래그 치환 콘크리트의 염화이온 침투 저항성 검토)

  • Cho, Hyeon-Seo;Kim, Min-Hyouck;Lee, Gun-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.11a
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    • pp.166-167
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    • 2019
  • In this study, to test the performance of concrete used as a concrete admixture as a recycling method of CGS, gypsum was mixed and the chloride ion penetration resistance test of CGS and BFS substituted concrete was conducted. As a result, it was found that without gypsum type test specimen, the CGS sustituted test specimens had lower chloride ion penetration resistance than the BFS substituted specimens. When gypsum was added, it was confirmed that the chloride ion penetration resistance was poor regardless of the type of admixture. In addition, it was confirmed that both admixtures were less resistant to chloride ion penetration than OPC, regardless of the presence of gypsum. However, considering the uneven quality variation of coal, which greatly affects the quality of CGS, further research is needed.

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A Standard Test Methods of Resistance to Root Penetration for Waterproofing and Rootproofing Membrane Using Green Roof System (인공지반녹화용 멤브레인 방수 및 방근재료의 방근성능 평가 방법 제안 연구)

  • Lee, Jung-Hoon;Seon, Yun-Suk;Kwak, Kyu Sung;Oh, Sang-Keu
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2009.11a
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    • pp.141-148
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    • 2009
  • The purpose of this paper is to propose a standard test methods of resistance to root penetration for waterproofing and rootproofing membrane using green roof system. Green roof system is considered to be an important subject in construction industry for green growth project. At the same time, we have to consider the counterplan for protection the damage of waterproofing layer and concrete substrate from the penetration of plant root. But many kinds of materials for protection from root penetration are using in construction field. But the performance of those materials is not clear, and there is not test methods for the evaluation of performance. So in this paper, based on the research results of 4 institutes during four years and foreign cases, we made a standard test methods of resistance to root penetration for waterproofing and rootproofing membrane using green roof system. This test method deals with about environmental condition of laboratory, experimental facilities, kinds of plant, specimen of test, management methods, evaluation duration and documents, etc.

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Characteristics of the Strength Change of Dredged Soil by Tide Influence (조석 영향에 의한 해성준설토의 강도변화 특성에 관한 연구)

  • Chun, Byung-Sik;Kim, Bong-Su;Lee, Won-Taek;Do, Jong-Nam
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.1071-1074
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    • 2008
  • In this study, the behavior of dredged soil was measured by repeated tide and analyzed the change of settlements and cone penetration resistance by centrifuge model about dredged soil of Kunsan-Janghang site that maximum tidal range is 7.4m. Consequently the settlements of dredged soil by repeated tide in the 2nd month was 0.489 m. After 12th month, the total settlements was 0.524 m in the model. It meaned the settlements of dredged soil by repeated tide in the 2th month was 80% of the settlements. Also, with the lapse of time, cone penetration resistance increased centrifuge model test for catching the strength change of dredged soil by repeated tide. After 10th month, there were not almost changes. cone penetration resistance in 10th month was measured more 3.5~5.6 times than that in its early stages. Also, with the lapse of time, cone penetration resistance increased almost linearly. And, when we surveyed the relation between cone penetration resistance and time, as depth increased, cone penetration resistance rose.

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Evaluation of Applicability of penetrating-type Nano-Coat for Preventing Deterioration of Concrete (침투형 Nano-Coat를 이용한 콘크리트 열화 방지 적용성 평가)

  • Lee, Jun Hee;Kim, Jo Soon;Sim, Yang Mo;Lee, Seung Woo
    • International Journal of Highway Engineering
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    • v.19 no.2
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    • pp.7-15
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    • 2017
  • PURPOSES : Infiltration of moisture, polluted material, and deicer into concrete, accompanied by freeze and thaw can cause significant deterioration of concrete pavement. In order to protect concrete from deterioration, it is necessary to prevent the infiltration of these concrete external materials. The moisture-repellent agent, which is a surface treatment and maintenance material added to concrete structures to render them water resistant, has advantages such as prevention of water infiltration and security against air permeation. Nano-coat, which is referred to as silicon hydride, is typically used as a moisture-repellent agent. Therefore, in this study, an attempt is made to use penetration-type Nano-coat as an alternative in order to evaluate its applicability through environmental resistance tests. METHODS : This study aimed to evaluate the applicability of penetration-type Nano-coat, which can provide water repellency to concrete, in concrete pavements, through various environmental resistance tests such as freezing and thawing resistance, chloride ion penetration resistance, and surface scaling resistance tests. The applicability of penetration-type Nano-coat was demonstrated based on the specification of KS F 2711, KS F 2456, and ASTM C 672. RESULTS :In the case of penetration-type Nano-coat applied on sound concrete, an increase in concrete durability was demonstrated by the negligible chloride ion penetrability and the absence of scaling, as revealed by visual observation of the surface, after 50 cycles of scaling resistance test. In addition, test result of the application of penetration-type Nano-coat on deteriorated concrete established that concrete surface pretreated by grinding provided improved durability than non-treated concrete. CONCLUSIONS :This study indicates that penetration-type Nano-coat is applicable as an effective alternative, to increase the durability of concrete structures. In addition, it was known that pretreatment of deteriorated concrete surface, such as grinding, is required to improve the long-term performance of concrete pavement.