• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.983-986
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• 2007

Concrete surface grinding is required for flatness and adhesiveness of concrete surface. The procedure is, however, labor intensive and has a hazardous work condition. Also, the productivity and the quality of concrete surface grinding depend on the levels of worker. Thus, the development of remote controlled concrete surface grinding equipment is necessary to prevent the environmental pollution and to protect the workers from hazardous work condition. However, it is difficult to evaluate the grinded surface objectively in a remote controlled system. The machine vision system developed in this study takes the images of grinded surface with the network camera for image processing. Then, by representing the quality test results to the graphic MMI program of the remote control station, the quality control system is constructed. The machine vision algorithm means the image processing algorithm of grinded concrete surface and this paper presents the objective quality control standard of grinded concrete surface through the application of the suggested algorithm.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.929-933
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• 2007

Concrete Pavement Cutting Operation have Labor-intensive features. And Cutting Operation quality and productivity is influenced by operator's experience. Moreover Workers have risk of safety concerns. Therefore we need Concrete Pavement Cutting Operation automation system and system support software development on the economics. First of all we have to develop driving Path Planning for Concrete Pavement Cutting automation system. If result of Path Planning connect with automation system, Weak points is a complement to the existing Path Planning and we can obtain effective automation system. Consequently this paper suggest method of Autonomous Driving Path Planning for Concrete Pavement Cutting Operation And the Path Planning system application.

• Magazine of the Korea Concrete Institute
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• v.14 no.6
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• pp.22-31
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• 2002

콘크리트 블록에는 속빈 콘크리트 블록, 치장 콘크리트 블록, 형틀 콘크리트 블록, 콘크리트 적층 블록 등이 있고, 콘크리트 적층 블록을 제외하면 모두 건축용으로 널리 쓰이는 재료이다. (1) 속빈 콘크리트 블록 속빈 콘크리트 블록이란 보강근을 삽입하는 속빈 부분을 갖고, 블록 벽체로 외력을 부담하는 것을 말한다. 속빈 콘크리트 블록은 건물의 경량화와 시공 기간의 단축이 가능하기 때문에 (그림 1)과 같이 벽체용으로 사용되거나 또는 칸막이용 등으로 많이 사용되는 대표적인 조적재이다 (2) 치장 콘크리트 블록 치장 콘크리트 블록은 철근으로 보강할 수 있는 공동이 있고, 미리 표면에 연마, 절삭, 씻어 내기, 쪼아 내기. 스플릿, 슬럼프, 리브붙임 등의 치장 마무리가 되어 있는 블록을 말한다. 도장 또는 착색만에 의한 치장 블록은 포함하지 않고 있다. 치장 블록은 주로 (그림 2)와 같이 담장에 많이 사용되고 있다. (3) 형틀 콘크리트 블록 형틀 콘크리트 블록은 형틀 콘크리트 블록조에 사용되는 것을 형틀 콘크리트 블록조란 형틀 블록을 조합하여 형틀로 하고, 그 중공부에 철근을 배치하고 콘크리트를 타설하여 내력벽을 형성하는 건축구조를 말한다. 형틀 블록을 조적한 후 외부에 나타나는 면에는 스플릿, 연마, 절삭, 씻어 내기, 쪼아 내기 등의 치장을 하기도 한다.(중략)

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1683-1691
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• 2013

Concrete surface grinding is frequently used for flatness of concrete surface, concrete pavement rehabilitation, and adhesiveness in pavement construction. The procedure is, however, labor intensive and has a hazardous work condition. Also, the productivity and the quality of concrete surface grinding highly depend on the skills of worker. Thus, the development of remote controlled concrete surface grinding equipment is necessary to prevent the environmental pollution and to protect the workers from hazardous work condition. However, it is difficult to evaluate the grinded surface objectively in a remote controlled system. Also, The machine vision system developed in this study takes the images of grinded surface with the network camera for image processing. Then, by representing the quality test results to the integrated program of the remote control station, the quality control system is constructed. The machine vision algorithm means the image processing algorithm of grinded concrete surface and this paper presents the objective quality control standard of grinded concrete surface through the application of the suggested algorithm.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.2
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• pp.153-170
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• 2022

Waterjet has been comprehensively used in urban areas owing to a suitable technique for cutting concrete and rock, and low noise and vibration. Recently, the abrasive waterjet technique has been adopted and applied by the Korea Atomic Energy Research Institute to demolish concrete plugging without disturbing and damaging In-situ Demonstration of Engineered Barrier System in the disposal research tunnel. In this study, the use of abrasive waterjet in the tunnel was evaluated for practical applicability and the existing cutting model was compared with the experimental results. As a variable for waterjet cutting, multi-cutting, water flow rate, abrasive flow rate, and standoff distance were selected for the diversity of analysis. As regarding the practical application, the waterjet facilitated path selection for cutting the concrete plugging and prevented additional disturbances in the periphery. The pump's noise at idling was 64.9 dB which is satisfied with the noise regulatory standard, but it exceeded the standard at ejection to air and target concrete because the experiment was performed in the tunnel space. The experimental result showed that the error between the predicted and measured cutting volume was 12~13% for the first cut and 16% for second cut. The standoff distance had a significant influence on the cutting depth and width, and the error tended to decrease with decrement of standoff distance.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.1
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• pp.161-182
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• 2018

We carried out a series of linear cutting machine tests to assess the cutting performance of a pick cutter in sedimentary rock. The specimens were Linyi sandstone from China and Concrete (rock-like material, conglomerate). Using the small scaled LCM system, we estimated the cutter force and specific energy under different cutting conditions. The cutter forces (cutting and normal) increased with penetration depth and cutter spacing in two rock types, and it was affected by the strength of specimens. On the other hand, the ratio of the peak cutter force to the mean cutter force was influenced by cutting characteristic and composition of rock rather than rock strength. The cutting coefficient was affected by the friction characteristic between rock and pick cutter rather than the cutting conditions. Therefore, the optimal cutting angle can be determined by considering of cutting coefficient and resultant force of pick cutter. The optimum cutting condition was determined from the relationship between the specific energy and cutting condition. For two specimens, the optimum s/p ratio was found to be two to four, and the specific energy decreased with the penetration depth. The result from this study can be used as background database to understand the cutting mechanism of a pick cutter, also it can be used to design for the mechanical excavator.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.15-16
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• 2010

The field experiments and analyses were performed to apply Post-Tensioned Prestressed Concrete Pavement(PTCP) at the Weigh-in-Motion(WIM) sensor installed sections. The experimental results showed that PTCP could be acceptable for WIM sections because the displacements were negligibly smaller at the cutting location for sensor installation.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.72-77
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• 2018

In this study, cutting robot system which could cut lateral protrusion into main pipes at the connection of sewer pipes was developed. In addition, the cutting test of the robot for the lateral protrusions were performed. The test parameters included materials used in the main pipes and diameters of the pipes, and materials used in the protruded pipes. The materials type of the main pipes were concrete and PE, and the diameters of the pipes were 300 and 500 mm. The materials type used in the protruded pipes were PE and PVC, and the diameter of the pipes was 100 mm. Remaining length of each lateral protruded pipe was less than 5 mm which was an target value of cutting performance. It showd that test results were within the target value. Therefore, in the repair of sewer pipes, the lateral protruded pipes can be cut by using the robot system developed in this paper.

• 한국도로학회:학술대회논문집
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• 2009.11a
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• pp.493-500
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• 2009

• International Journal of Highway Engineering
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• v.7 no.1 s.23
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• pp.83-92
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• 2005

Maturity method is a non-destructive method for estimating in-place concrete strength as a function of time and temperature. The main objective is to use maturity method determining joint sawing and traffic opening time for whitetopping construction in Korea. Another objective is to investigate the influence of air temperature in the correspondence to slab temperature and maturity value. For determining the joint sawing and traffic opening time, thermachron i-button and strain gage were inserted in the fresh concrete in the slab and a maturity value was calculated at desired times. In-place strength was then estimated from a pre-established relationship between maturity values and compressive strength. The results showed that there are significant differences between the estimated strength obtained from maturity curve and in-place concrete strength. The reasons are that the gain of in-place concrete strength was influenced by several factors in the field such as curing conditions, air temperature, and wind speed etc. Also, the results showed that air temperature had significant influence on slab temperature and maturity value The slopes of maturity curves exponentially decrease as air temperature decreases. This means that maturity value sharply dropped as air temperature decreases.