• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.594-596
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• 2012

Currently, demands for outdoor broadcasts and concerts are increasing. Due to severe circumstance of outdoor places like rain, wet-damage in moved loudspeaker may occur. Experimental approaches to improve waterproof-effect for movable loud speaker have been investigated in this studies. For performance test of loud speaker, enclosures were made by MDF(Medium Density Fiberboard). Three types of finishing material, general paint, sheet paper and FRP(Fiber Reinforced Plastics) are proposed for comparing waterproof-effects.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1964-1969
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• 2010

Recently, as construction market scale is getting bigger and transportation industry is developing, the underground structure construction such as subway, tunnel (excavation box) or shield tunnel structure is becoming more diverse, and its demand is gradually increasing. However, for the concrete structures constructed underground, the water leakage is occurred due to the expansion joint and construction joint, or movement, uneven settlement, excessive load and vibration during application causing cracks. Many waterproofing method and materials are used in jobsites, but areas such as underground railroad and subway that has movement and vibration at all times, the ability of waterproofing layer is declined causing repetitive water leakage due to crack, erosion and separation, which is a vicious cycle. Therefore, this study evaluates the responsiveness to a movement for adhesive/flexible waterproofing material that can cope with the vibration and the movement of the structure. Also to recommend a waterproofing technology that can cope with structure movement through examples of actual jobsite applications such as subway and tunnel where there are constant movement and vibration.

• Magazine of the Korean Society of Agricultural Engineers
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• v.6 no.2
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• pp.787-802
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• 1964

• Geotechnical Engineering
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• v.26 no.11
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• pp.18-25
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• 2010

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.463-469
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• 2018

A currently used roof green system with multi layers has a low constructability. Therefore a new integrated waterproof & root barrier sheet and roof green box unit system was developed using steel plate fixture and cone type fixture by electromagnetic induction heating method. This study was proceeded to evaluate adhesion performance of two types of fixtures on Engineering PE, TPO, PVC sheet in a normal condition, repeated heating and cooling condition. As a result, adhesion load on Engineering PE sheet showed the highest value. The adhesion loads of steel plate fixture showed higher value as heating temperature was getting higher. However adhesion loads of cone type fixture showed opposite tendency. Regarding to the test conditions, test results of normal condition, repeated heating and cooling condition showed same value. The cone type fixture using butyl tape showed 7 times lower adhesion load than that of cone type fixture using electromagnetic heating and 28% lower adhesion load in a repeated heating and cooling condition than a usual condition.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.2
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• pp.283-299
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• 2017

The leakage of tunnel causes the long-term durability of the structures such as concrete lining to deteriorate. The cause of durability degradation can be various substances contained in groundwater such as chloride, sulphate, water, and gas. In this study, a series of test were carried out to determine the watertightness performance and the resistance to salt water of the spray-applied membrane used as non-structural rock support or as a waterproof material for tunnels. As a result, it was found that the penetration of water could occur in a specimen, and the reason was that the internal pores generated by the mixing of the liquid polymer and the powder material and the internal pores were connected by the water pressure. The tensile strength of the test specimens immersed in distilled water and saline water was found to be reduced to less than half of the tensile strength in normal condition. In addition, The elongation was measured to be higher in distilled water than in salt water. However, this result will require further investigation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05c
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• pp.89-97
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• 2009

As landscaping building roofs and concrete structures increase gradually for low carbon green growth policy of government, But waterproofing membranes of those structures are effecting by root penetration of landscape plant. 80, we progressed study about test method for fast evaluating root resistance of waterproofing materials jointly with Tokyo Institute of Technology. The result of the study is as follows: (1) The penetrating load of the needle at the displacement speed of 1mm/min was measured for various membrane to basis and lap joints of membrane, the load force was $3{\sim}50$ N by material variously. (2) According to the test method of deriving rhizomes of bamboo grass to basis and lap joints of membrane, there were no penetrated membrane until present, but need persistent observation. (3) Test method of deriving rhizomes of bamboo grass to basis and lap joints of membrane can shorten from period of 2 years to 1 year for testing. Because rhizomes of bamboo grass can grow from May to September, test is possible in same period.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.189-190
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• 2018

KS standards mostly relate to single component material evaluation, so in cases of underground structure environments, most cannot predict the existing composite forms of deterioration, resulting in the applied waterproofing materials becoming unable to respond to these damaging factors. Current domestic waterproofing market in Korea mainly uses single-ply waterproofing materials comprised of coatings or waterproof sheets and two or more-ply composite waterproofing methods. In order to evaluate these types of composite waterproofing systems, a new test equipment and method that incorporates various deterioration conditions (joint displacement, chemical exposure, water pressure etc) was developed. In a comparison testing, the results showed that flexible type materials have higher response performance towards joint displacement than the hardened material.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.648-657
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• 2014

This paper is about the study on a newly developed small waterproofed 4-axis robot arm and the analysis of its kinematics and dynamics. The structure of robot arm is designed to have Pitch-Pitch-Pitch-Yaw joint motion for inspection using a camera on itself and the joint actuator driving capacity are selected and the joint actuators are designed and test for 10m waterproofness. The closed-form solution for the robot arm is derived through the forward and inverse kinematics analysis. Also, the dynamics model equation including the damping force due to the mechanical seal for waterproofness is derived using Newton-Euler method. Using derived dynamics equation, a sliding mode controller is designed to track the desired path of the developed robot arm, and its performance is verified through a simulation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.118-125
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• 2016

This paper proposes the appropriate waterproofing methods for underground structures after applying different types of waterproofing materials on the concrete test specimens and selecting the best results out of humidity testing in winter conditions. Results of the testing showed that the underground structures absolutely require relevant waterproofing application based on the environmental conditions; when applied with interior waterproofing, the results showed that the concrete maintained high level of humidity and reinforcing steel within the concrete layer corroded. However, when applied with exterior waterproofing, it was shown that the waterproofing layer prevent direct contact with water and concrete, thereby protecting the concrete structure and improving overall durability. It follows that during underground structure construction, exterior waterproofing methods are have shown by an effective method for improving the durability as well as providing a comfortable interior environment for users.