• Journal of the Korea Institute of Building Construction
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• v.15 no.2
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• pp.185-192
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• 2015

Expansion joint is the essential element of the bridge in many cases. When the bridge faces chloride of preventing freezing on the surface of the bridge, the expansion joints is damaged significantly, thus this reduces service life and increases maintenance cost of the bridge. As a solution of this problem, new technology using high ductile materials for the joint without expansion joint was developed and in this research, crack control performance, preventing leaking after the cracking, and chloride resistance were experimentally evaluated. As a result of the experiment, with PCM and FRC materials, the connecting joint suffered poor crack dispersion and severe damage by the chloride penetration while with high-ductile material, the connecting joint dispersed the tensile deformation to microcracks stably up to 7.5mm. Furthermore, under the sever conditions, the leaking was prevented and penetration of chloride ions was prevented after the crack occurred.

• International Journal of Highway Engineering
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• v.4 no.2 s.12
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• pp.33-42
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• 2002

The cracks in the pavements result from drying shrinkage, temperature change, repeated traffic loadings and so on. The reduction of soil support, spatting and many local failures are caused by water and incompressible foreign materials infiltrated into the cracks. In order to reduce this kind of problems the crack width must be controlled and managed by the accurate measurement. The current method is a visual survey using a microscope, which requires traffic blocking. The purpose of this study is to find the best condition to measure accurate crack width using automated pavement condition survey equipment running at the similar speed as other vehicles. In this study pavement surfaces are filmed on an enlarged scale by the camera with a zoom lens, and then the proper focal distance is determined according to the crack width through a pilot survey. The conditions for measurement of the accurate crack width using the image processing technique are suggested by comparing crack widths surveyed using a microscope in the field with those computed by various factors in the image processing program, STADI-2. In conclusion, the camera with a focal distance of 75m could detect crack range of 0.5mm$\sim$1.2mm In width with an accuracy of 80% for CRCP. The camera with a focal distance of 12.5mm could detect crack range of 1.8mm$\sim$3.3mm in width with an accuracy of 90% for asphalt pavement.

• Journal of the Society of Disaster Information
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• v.16 no.3
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• pp.449-457
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• 2020

Purpose: The Seoul Metropolitan Government classifies the cavity risks into emergency, priority, general, and observation grades in consideration of the cavity size, asphalt pavement thickness, and pavement depth based on the cavity management grade criteria of Seoul. In this study, the depth of cracking was measured at 17 cracks identified by checking the pavement condition of the cavity at 265 cavities found in the 2019 cavity investigation service. Method: In the first phase, crack width and depth were measured using a vernier caliper, taper gauge, and depth gauge to check the cracks of the identified cavities. In the second phase, the location of the largest crack in the upper road surface was confirmed, and A.C. was drilled to further measure the crack depth. Results: As a result, the cavity management level was raised in nine of the 17 test cavity identified. Therefore, in case of emergency and priority recovery, the grade should be adjusted according to the depth of pavement crack and the thickness of residual A.C. pavement. Conclusion: In the case of cracks in the upper part of the cavity, the crack progression must be determined through the perforation and the remaining asphalt concrete thickness must be determined to determine the cavity grade.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.758-764
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• 2019

The chassis of the Korean light tactical vehicle adopts a frame-on-body structure that uses lightweight design technology in terms of equipment operating characteristics. Military vehicles are operated in much harsher conditions compared to civilian vehicles, including mountainous terrain, especially steep slopes. Due to this characteristic, frame-welded cracks were found on some military vehicles. Therefore, in this paper, road damage analysis was conducted by identifying various roads including the military unit's road. The result confirmed that the operating environment of some military units' tactical road was much harsher than the endurance road test condition. A solution was derived through defect analysis, design review, and actual vehicle driving test. This study can be used as a reference by suggesting the development direction for the durability test of a new vehicle.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.2
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• pp.237-244
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• 2024

Pavement management systems (PMS) provide procedures to quantify road serviceability based on pavement conditions such as cracks and plastic deformation and suggest proper maintenance methods. The deterioration of the road pavement is relevant to the time although the quantifications on road serviceability in PMS present road surface conditions at the evaluation. More systematic evaluation on road serviceability may need time-dependent factors of road environments and that can improve PMS. Rainfall, temperature and vehicle loads can be environmental factors for road serviceability evaluation. As no data are avablie that can link between road conditions and environmental road factors, we conducted experiments to suggest economical devices and methods to obtain relevant data. We used temperature sensors and accelerometers with Arduino to measure road surface temperature and dynamic loads and provide data to improve pavement serviceability evaluation.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.99-109
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• 2009

Fine-size exposed aggregate portland cement concrete pavements (FEACP) have surface texture of exposed aggregate by removing upper 2$\sim$3mm mortar of surface of which curing is delayed by using delay-setting agent. FEACPs have advantages of maintaining low-noise and adequate skid-resistance level during the performance period than general portland cement concrete pavements. It is necessary to ensure the durability environmental loading to prevent unexpected distress during the service life of FEACP. In the process of curing, volume change accompanied change in by moisture and temperature could be an important cause of crack in concrete to construct for successful FEACP, The use of chloride containing deicer may accelerate defects of concrete pavement, such as crack and scaling. This study aim to evaluate environmental loading resistance of FEACP, based on the estimation of shrinkage-crack-control-capability by moisture evaporation and scaling by deicer in freeze-thaw reaction.

• Journal of Korean Society of Forest Science
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• v.106 no.1
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• pp.70-76
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• 2017

Among the forest road pavement methods, the majority of current constructions utilize concrete pavements but it has disadvantages as follows: many cracked concrete pavements generated by the erosion of underlying soil layers, could not be used as forest roads in steep slope during winter, and cement contains hazardous chemicals (hexavalent chromium, etc.). In order to supplement the limitations of the use of concrete pavement, this study was conducted to investigate the operation process and cost, the strength and compaction of the experimental forest road pavement(85 m) utilizing eco-friendly solidification material at Goryeong-gun, Gyeongsangbuk-do. The work elements of experimental forest road paving were classified into: preparation, Roadbed excavation, Roadbed grading, subgrade compaction, form work, collection and selection of site soil, mixing site soil and eco-friendly solidification material, paving by eco-friendly solidification material, compaction by vibrating roller and curing. The result of economic analysis using construction cost shows that for concrete costs total to $38,681won/m^3$ while for the eco-friendly paving material it is $38,245won/m^3$. Thus the construction costs for concrete and the eco-friendly paving material are similar. And the results of the Schmidt Hammer test for strength analysis by curing period are 10.5-13.5 MPa for 7 days, 18.1-22.7 MPa for 14 days, and 20.8-23.0 MPa for 28 days.

• Korean Journal of Construction Engineering and Management
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• v.6 no.4 s.26
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• pp.172-180
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• 2005

The purpose of this study is to suggest a new SRC(Steel Ready mixed Concrete) lining board. The research method of this study includes problem analysis of existing lining boards a constant load test and a fatigue test. The results of this study are as follow : 1) the suggested new lining board improves the function and reduce slipperiness than existing lining boards. 2) the strength of the new SRC lining board is analyzed as superior than existing lining boards from the results of constant load test and fatigue test.

• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.535-545
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• 2022

The purpose of this study is to classify the various problems in surface road according to their severity and to propose a priority decision making process for road policy makers. For this purpose, the road problems reported by Cheok-cheok app were classified, and the EPDO was adopted and calculated as an index of their severity. To test applicability of the proposed process, some images of road problems reported by the app were classified and annotated, and the Deep Learning was used for machine learning of the curated images, and then the other images of road problems were used for verification. The detecting success rate of the road problems with high severity such as road kills, obstacles in a lane, road surface cracks was over 90%, which shows the applicability of the proposed process. It is expected that the proposed process will make the app possible to be used in the filed to make a priority decision making by classifying the level of severity of the reported road problems automatically.

• International Journal of Highway Engineering
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• v.9 no.3
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• pp.111-121
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• 2007

During the whole month of December in 2005, Korea experienced both heavy snowfall and freezing temperature in southeast regions, which had caused frost related damages to many pavements laid on top of box culverts. In-situ observation revealed that the formation of ice lenses in subgrade and subsequent unbound layers led to upward heaving and transverse cracks in concrete and asphalt pavements. This has affected the long-term performance of pavements, as well as has threatened drivers' safety for a while. Recently, Korea Expressway Corporation has proposed a design guide to better protect newly constructed unbound pavement layers over culverts from frost heave. A trench drainage system has been selected to effectively draw off water and to alleviate pore-water pressure in soils during the coldest season. This paper presents experimental and analytical backgrounds behind this new design guide. Soil specimens retrieved from the sites are tested to quantify clay content and to estimate the permeability of subgrade. A 2-D ground seepage analysis has been conducted to better understand the changes in pore water pressures as a function of grain size. Finally, an optimum size of trench drainage is determined based on numerical analysis and workability in the field.