• 한국도로학회지:도로
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• v.10 no.4
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• pp.61-67
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• 2008

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.3
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• pp.246-254
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• 2013

This study is purposed to verify the safety of the floor of the children's playground using polyolefin foam waste and rubber paving. The critical fall height, walking suitability, long term physical fatigue expectation and slipperiness were tested. Polyolefin foam wastes in thickness of 30mm, 50mm and 70mm were prepared with paving the rubber paving materials in 12mm and 15mm thickness respectively. The test on the critical fall height was carried out according to KS G 5758:2009. The floor hardness test equipment (O-Y HMA) was used for the test on hardness of the floor from a viewpoint of walking suitability and fatigue. A portable slipperiness tester (ONO PPSM) was used for slipperiness test. It was revealed from the test that the floor made of the polyolefin foam waste and rubber paving were considerably safe from a viewpoint of impact absorption. With regards to the hardness of the floor, it was shown the excellent performance in the aspects of walking and fatigue for male. But it was not suitable with walking on the shoes(middle heels) for female. And they will be very fatigue if they were in a long time walking or standing. As far as the slipperiness is concerned, it was shown that it was comparatively safe for the ordinary motions even though the surface was wet.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.579-582
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• 2010

We propose a method of using the three dimensional characteristic information to classify the front environment in travelling by using the images captured by a CCD camera equipped on a mobile robot. So, this paper proposes the method of deciding the travelling direction of a mobile robot with using input images based upon the suggested algorithm by preprocessing, and verified the validity of the image information which are detected as obstacles by the analysis through neural network.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2396-2401
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• 2009

This study is on development of UV-cured hard coating compounds which have more improved abrasion resistance than existing UV-cured urethane-acrylic resin, to prevent a surface of a widely used PVC tile as a constructive material from being scratched. To make a high abrasion resistant hard coating solution compared to UV-cured urethane-acrylic resin which has no abrasion resistance and been used for PVC tiles, we added powder substances of different abrasion resistant level, $Al_2O_3$(Al-160SG-3), $Al(OH)_3$(SH-8W), $SiO_2$(KS-5000), etc., to the resin, changing their contents from 10% to 30% against quantities of resin, and compounded it using Ring-Mill. After coating PVC tiles with the hard coating solution using bar-coating method that can adjust a thickness, we estimated some surface properties-abrasion resistance, pencil hardness, adhesive power, thickness of coating, and so on. As a result, a hard coating solution added 30% $Al_2O_3$ powder to the resin had the finest surface properties-the first grade in abrasion resistance, H in pencil hardness, 100% in adhesive power, and a hard coating solution which showed excellent solidity and abrasion resistance has smaller particle size, higher powder content, and thicker coating thickness.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.27-34
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• 2017

Recently, the importance of the industrial warehouse floor has been increasing due to the development of the distribution and logistics industry. In this present study, an early-hardening polymer floor mortar which can compensate for the limitation of conventional cement based floor mortar regarding fluidity and long curing time was developed. In order to achieve the early-hardening of mortar characteristic ultra rapid hardening cement was used as binder. Four types of mixture proportions in accordance with the vinyl acetate ethylene(VAE) polymer contents with range from 10% to 20% and the other proto proportion without VAE polymer were designed. Mechanical experiments including the fluidity test, compressive strength test, bending test, bond test, and abrasion test were conducted for all mixture proportions. From the flow test result, it was possible to achieve the high flow with 250 mm by controlling the amount of superplasticizer. The incorporation of VAE polymer was found to affect the compressive strength reduction, however, the flexural strength was higher than that of the proto mixture, and it was evaluated to increase the compressive strength / flexural strength ratio. Moreover, at least 2.6 times higher bond strength and more than 4 times higher abrasion resistance were secured. From the mechanical experiments results, the optimum mixing ratio of the VAE polymer was determined to be 10%. As a result of application and monitoring, it shows that it has excellent resistance to cracking, discoloration, impact, and scratch as well as bond performance compared to the cement based floor mortar.

• Electric Engineers Magazine
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• s.371
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• pp.40-41
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• 2013

2013. 6. 16(월) 11:00경 경기도 여주군 소재 A공장내 지상 수전설비(H변대)에서 전기설비 안전관리담당자(남, 63세)가 컷아웃스위치(C.O.S)를 맨손으로 투입하다가 감전되어 7m 높이의 바닥으로 떨어져 사망한 재해임.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.101-107
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• 2017

Over-break, which is excavated larger than planned line at tunnel excavation, is inevitable due to the nature of blasting. But regarding the bottom of the foundation, most of the domestic ordering organizations pay only 10 cm thick filled concrete when pouring concrete due to over-break. In accordance, the construction cost will increase greatly if all the depths of the designed over-break are filled only with concrete. When tunnel excavation occurs, concrete filling of 18 MPa(T = 100 mm) and 150 mm~237 mm auxiliary concrete layer and 240 mm concrete track(TCL) are applied to the upper part. The concrete is installed in an excessive amount of about 600 mm between the lower part of the rail and the tunnel rock bed. Therefore, in this study, it is necessary to analyze the concrete crack structure according to the depth of the existing tunnel and the modified tunnel section, and to evaluate the adequacy of the required thickness of the tunnel floor concrete for securing the crack stability of the concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.757-760
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• 2008

The latex modified concrete was applied to baseplate of road bridge after 2000 year. This is in the limelight of stability to be missing problems. But, The baseplate of railroad bridge being experience to difficulty that searching method substituted for bridge waterproofing. In this study, I would like to application on P.C.L layer of railroad bridge using the property and merit of L.M.C. As a result performance test about six item, L.M.C was confirmed no problem to performance and application of bridge waterproofing.

• Elastomers and Composites
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• v.38 no.2
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• pp.122-127
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• 2003

Compounding, using such thermoplastic elastomer as styrene-ethylene-butadiene-styrene (SEBS) blended with polypropylene(PP), oil, and other ingredients, was studied to develop a new material with excellent impact resistance and resilience for the replacement of environmentally toxic PVC sheet. Hardness decreased linearly with oil content in the SEBS/oil blend, and the tensile strength increased with PP content whereas elongation showed no effects over 50 phr of PP in SEBS/oil/PP blend. In the practical SEBS composition, proposed to replace the PVC sheet material, tensile and tear strength, as well as hardness, increased proportionally with PP content, while melt index decreased.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.3
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• pp.125-133
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• 2011

The requirement for durability of concrete bridge deck is increasing as the deterioration for the concrete bridge deck exposed to severe environment has been increased. For this reason, the concern about high-durable concrete is being high. Recently, a metakaolin is highly spotlighted as new admixture because its strength and durability are equivalent to silica fume. On the other hands, there are few researches for the metakaolin concrete bridge deck in domestic. So many various long-term data on the mechanical property and durability is needed to apply metakaolin concrete at the concrete bridge deck construction field. This study is aim to evaluate the long-term mechanical properties and durability of metakaolin concrete bridge deck with curing age. Mechanical properties are estimated by the compressive and flexural strength, and the drying shrinkage, the chloride resistance, the scaling, and freezing and thawing characteristics are compared with curing age. According to the results, when the metakaolin concrete is used, the development of compressive and flexural strength proceed in both the early and old ages. It is also improved the resistance of chloride penetration, freezing and thawing in concrete. It was showed that replacement of metakaolin was efficient for the reduction of the drying shrinkage.