An Investigation of the Deterioration Characteristics of Concrete Bridge Decks with Asphalt Concrete in Korea

Jiyoung Rhee,Hongsam Kim,Changkwon Ock,최재진 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

One of the most serious problems in maintaining and rehabilitating bridges is the deterioration of the asphalt concrete overlay, and subsequent deterioration of the deck concrete under the overlay. Although it is important from the perspective of the road managers to evaluate the exact status of the bridge deck thorough detailed examination, it still remains a difficult problem to determine the condition of the bridge deck under the overlay without coring samples. Accordingly, it is still a common and daily practice to examine the overlay surface and bottom of the bridge deck to evaluate its condition. Instead, this study collected cores from bridges with asphalt concrete in public service, which had manifested deterioration of the concrete deck. The study aimed to delineate the relationship between the deterioration status of the concrete bridge deck and the asphalt concrete overlay, waterproof layer, cover thickness of rebar, corrosion of rebar, and chloride contents in the concrete. The results of this investigation found that the deterioration of the concrete of the bridge deck was closely related to the functionality (performance) of the waterproof layer, and the deteriorated depth was significantly related to the average chloride content in the cover concrete of the top rebar.

신개념 FRP-콘크리트 합성 바닥판의 구조 형식 및 거동 특성

조근희(Cho Keunhee),박성용(Park Sung Yong),조정래(Cho Jeong-Rae),김병석(Kim Byung-Suk) 대한토목학회 2007 대한토목학회논문집 A Vol.27 No.3A

새로운 형식의 FRP-콘크리트 합성 바닥판을 제안하고 설계 개념 및 구조 형식 등을 소개한다. 또한 바닥판으로서의 성능을 검증하여 실제 적용 가능성을 확인하고자 한다. 제안된 FRP-콘크리트 합성 바닥판은 하부에 인발(pultrusion)공정으로 제작된 중공 GFRP 패널을 두어 영구 거푸집 및 주요 인장부재로 활용하고, 그 위에 콘크리트를 타설하는 신개념 바닥판 형식이다. FRP와 콘크리트 사이의 합성을 위해 규사코팅과 전단연결판을 도입하고 양면전단실험을 통하여 합성 성능이 충분함을 확인하였다. 또한 바닥판과 거더 사이의 합성 효과를 고찰하고 스터드 연결방식에 대해 직접전단실험을 수행하였다. 스터드는 프리캐스트 바닥판의 경우와 비슷한 수준의 극한강도를 나타내어서 실제로 요구되는 성능을 만족함을 확인하였다. 또한 실물 크기의 바닥판에 대해 정적 및 윤하중 피로 실험을 수행하여 거동 특성을 고찰하고, 관련 설계기준을 만족함을 확인하였다. 이와 같은 점을 고려할 때 본 연구에서 제안한 신형식 FRP-콘크리트 합성 바닥판은 기존 바닥판에 비해 시공성과 내구성이 향상되었음을 알 수 있었으며, 교량 바닥판으로서 적용성이 충분히 있음을 확인하였다. An innovative type of FRP-concrete composite deck is proposed, and its design concept and structural type are presented. The performances of the proposed system as a bridge deck are examined so as to verify its actual applicability. The proposed FRP-concrete composite deck is innovative regard to its bottom constituted by a hollowed GFRP panel fabricated by pultrusion, which plays the role of permanent form and main tensile member, and on which concrete is cast. The composition of FRP and concrete is realized by coarse sand coating and shear connecting plate, which has been verified to develop sufficient composite effect by means of push-out tests. Moreover, the composite effect between the deck and girder is examined and pure shear tests were carried out on the shear stud connection. The studs were seen to develop similar ultimate strength than precast deck, which satisfied the actually required performances. In addition, a full-scale deck was built and subjected to static and wheel load fatigue tests so as to investigate its behavioral characteristics. Test results verified that the proposed deck satisfies the relevant design codes. Consequently, this innovative FRP-concrete composite deck proposed in this study is seen to offer improved constructability and durability compared to former decks, and to present sufficient practicability as a bridge deck.

LB-DECK의 Lattice bar 높이 변화에 따른 합성거동 연구

노병철(Lho Byeong Cheol),조규대(Cho Gyu Dae) 대한토목학회 2007 대한토목학회논문집 A Vol.27 No.2A

본 연구는 교량바닥판의 한 형태인 LB-DECK의 내하력 증가와 구조적인 성능 향상을 위하여 Lattice bar의 높이를 135 ㎜에서 70 ㎜로 변경함에 따른 현장타설 콘크리트와의 합성거동 여부를 평가하는데 있다. 평가 방법은 Lattice bar 높이 135 ㎜와 70 ㎜의 두 가지 시편을 제작하여 재하 실험을 실시하였다. 실험결과 Lattice bar의 높이가 70 ㎜ 시편은 135 ㎜의 시편보다 17.1%의 극한모멘트 증가율을 보였으며, 이는 모멘트 팔길이의 증가에 따른 것으로 판단된다. 균열형상은 LB-DECK의 하부에서 시작하여 현장타설 콘크리트 하부로 진전되는 양상으로 LB-DECK의 접합면은 인장에 의한 지배를 받는 것으로 나타났다. 균열형상 및 중립축 변화를 분석한 결과, LB-DECK와 현장타설 콘크리트는 합성거동 함을 확인하였다. The experimental investigations for the flexural strength and composite behavior of a bridge deck with precast concrete panel form work called LB-DECK based on the height change of lattice bar from 135 ㎜ to 70 ㎜ to increase ultimate strength and construction ability. Two types of beams with LB-DECK were tested. Tested beams with 70 ㎜ lattice bar have 17.1% average ultimate strength than 135 ㎜ lattice bar due to the increase of moment arm. And the cracks are propagated from the bottom of LB-DECK to the bottom of plate with continuous pattern, and the upper part of LB-DECK is in tension. From the monitoring of crack patterns and neutral axis changes, a composite behavior is observed between LB-DECK and slab concrete.

Different Characteristics of Radar Signal Attenuation Depending on Concrete Condition of Bare Bridge Deck

이지영,심재원,기성훈,이상염 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.7

This paper examined the attenuation method, which is used abroad, to derive a method to evaluate the condition of bare concrete bridge decks using ground penetrating radar (GPR) technology. For this purpose, 12 GPR surveys of 10 bridge decks in public service from the beginning of its service to 25 years of service were carried out to examine the attenuation characteristics of GPR signals under various concrete conditions. The survey revealed the signal below the top rebar of concrete bridge deck under the condition of using de-icing chlorides for snow removal was not clear. Therefore, using the receiving wave signal from top rebar was reasonable when attenuation of GPR signal was to be used for bridge deck evaluation. Examining the signal attenuation by the condition of concrete, dispersion of the attenuated signal was overall large in the initial performance period. However, since this is not due to deterioration, exclusion of the large dispersion from the evaluation of bridge deck condition was desirable. The attenuation size was linearly proportional to its two way travel time (signal transmission time), i.e., the depth of the top rebar, in a sound bridge deck. Also, the dispersion of the attenuation was small and symmetric to the linear regression line. If the bridge deck was maintained adequately, the linear regression correlation was also maintained similarly for the next several years. However, if deterioration occurred to be accompanied by increased attenuation and dispersion, correlation coefficient of the linear regression line declined. Nonetheless, the upper value of the attenuation representing sound concrete condition was still tended to be linearly proportional to two way travel time. Since the attenuation quantity could result in considerable debilitation just by the construction error, it is necessary to deal with the depth-error of top rebar for evaluating the concrete condition by using the GPR signal attenuation. Calibration was carried out by deriving a linear regression line for the signal two way travel time and the upper 90th percentile values of the attenuation obtained from the top bar position of the bridge and then removing it from the total attenuation.

GFRP 근 보강 콘크리트 교량 바닥판의 설계지배인자

조정래 ( Jeong Rae Cho ),박영환 ( Young Hwan Park ),박성용 ( Sung Yong Park ),조근희 ( Kun Hee Cho ),김성태 ( Sung Tae Kim ) 한국안전학회(구 한국산업안전학회) 2015 한국안전학회지 Vol.30 No.6

In this study, the governing design factors of GFRP-reinforced concrete bridge deck are analyzed for typical bridges in Korea. The adopted bridge deck is a cast-in-situ concrete bridge deck for the prestressed concrete girder bridge with dimensions of 240 mm thickness and 2.75 m span length from center-to-center of supporting girders. The selected design variables are the diameters of GFRP rebar, spacings of GFRP rebars and concrete cover thicknesses, Considering the absence of the specification relating GFRP rebar in Korea, AASHTO specification is used to design the GFRP-reinforced concrete bridge deck. The GFRP-reinforced concrete bridge deck is proved to be governed by the criteria about serviceability, especially maximum crack width, while steel reinforced concrete bridge deck is governed by the criteria on ultimate limit state. In addition, GFRP rebars with diameter of 16 mm ~ 19 mm should be used for the main transverse direction of decks to assure appropriate rebar spacings.

에폭시 콘크리트를 사용한 조립식 교량 상판 연결부의 피로거동에 과한 실험적 연구

成基泰,李丞鏞 충주대 산업과학기술연구소 2000 産業科學論文集 Vol.8 No.-

열화손상이 발생된 교량 상판의 보수를 위해서는 교통흐름의 지체, 대중의 불편함 및 경제적인 손실이 불가피하다. 그러므로, 교통량이 적은 시간대에 신속하게 교량 상판을 보수 또는 교체할 수 있는 공법의 적용이 바람직하다. 이러한 공법 중의 하나가 조립식 교량 상판을 현장에서 에폭시 콘크리트로 연결하는 방법이다. 따라서, 본 연구는 이 방법을 사용하였을 때 에폭시 콘크리트 연결부의 역학적 특성과 이상 유무를 파악할 목적으로 실험적 연구를 실시하였다. 그 결과, 조립식 교량 상판의 에폭시 콘크리트 연결부는 최대 설계활하중을 초과하는 반복하중이 작용하여도 충분한 피로강도를 갖고 있음을 알 수 있었다. 또한, 연결부 경계면의 분리나 철근 겹이음부의 미끄러짐은 나타나지 않아 조립식 상판 콘크리트와 에폭시 콘크리트는 일체로 거동함을 확인할 수 있었다. Rehabilitation of the deteriorated bridge decks causes travel delay, public inconvenience and economic loss. Therefore, it is desirable to adopt deck replacement techniques that allow repair work to be completed rapidly during the periods of low traffic volume. Precast deck method using epoxy concrete is satisfactory for that purpose. The experimental study is performed to investigate the mechanical behavior and safety of precast deck joints using epoxy concrete. The results show that epoxy concrete joints in precast deck have a sufficient fatigue strength under the cyclic load beyond maximum design live load. And the interface between epoxy concrete and precast concrete is not separated, so it is concluded that precast concrete and epoxy concrete behavior like one material.

메타카올린 콘크리트 교량바닥판의 장기 역학적 특성 및 내구성에 관한 연구

양은익,김명유,양주경,박해균,최윤석 한국구조물진단유지관리공학회 2011 한국구조물진단유지관리공학회 논문집 Vol.15 No.3

가혹한 환경에 노출되는 콘크리트 교량바닥판에 대한 피해가 증가하면서 콘크리트 교량바닥판의 내구성 향상에 대한 요구가 증가하고 있다. 이에 따라 고성능 콘크리트에 대한 관심이 높아지고 있다. 최근, 새로운 광물질 혼화재로써 실리카흄과 같은 수준의 강도와 내구성 확보가 가능한 메타카올린이 높게 평가되고 있다. 이에 비해 국내의 메타카올린에 대한 연구 및 대체사용은 미진한 수준이며, 메타카올린 콘크리트를 교량바닥판에 적용하기 위한 검토도 매우 부족한 실정이다. 따라서 메타카올린 콘크리트를 교량바닥판에 적용하기 위해서는 장기적인 역학적 특성 및 교량바닥판에 요구되는 내구성에 대한 다양한 자료가 필요하다. 본 연구는 메타카올린 콘크리트를 적용한 교량바닥판의 장기적인 역학적 특성 및 내구성을 양생 재령에 따라 검토하는데 목적을 두었다. 역학적 특성은 압축강도 및 휨강도가 측정되었으며, 내구성의 경우는 건조수축, 염화물 저항성, 스케일링, 동결융해 저항성을 양생 재령에 따라 비교 평가하였다. 연구결과에 따르면, 메타카올린의 대체는 압축강도 및 휨강도 발현이 초기 및 장기 재령에서 우수하였다. 또한, 내구성 측면에서도 염화물 침투 저항성과 동결융해 저항성을 향상시켰다. 또한, 건조수축을 저감시키는 것으로 나타났다. 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.

교량 콘크리트 바닥판 열화 매커니즘과 유형에 따른 보수방안

정유석(Yoseok Jeong),이일근(Ilkeun Lee),민근형(Geunhyeong Min),김우석(WooSeok Kim) 한국콘크리트학회 2024 콘크리트학회논문집 Vol.36 No.4

최근 교량 바닥판 유지관리 실패로 인해 관련 사고가 빈번하게 발생하고 있어 체계적인 바닥판 유지관리 전략 수립이 필요한 시점이다. 이를 위해 본 연구에서는 바닥판 열화메커니즘 규명 및 바닥판 열화유형을 제안하고 그에 따른 보수보강 방안 및 선정방법을 제시하고자 한다. 콘크리트 바닥판의 열화 메커니즘은 상면에서 초기 결함, 미세균열, 중차량 피로로 인해 열화가 시작되고, 이 부위에 수분 및 염화물 침투, 동결융해, 중차량 피로에 의해 손상 면적과 깊이가 확대된다. 콘크리트 바닥판 보수공사는 열화깊이에 따라 교면재포장(TYPE A), 바닥판 부분단면복구공사(TYPE B), 바닥판 전단면복구공사(TYPE C)로 구분할 수 있다. 적정보수공법을 선정하기 위해 육안조사 및 상세조사를 통해 바닥판의 열화 정도(면적과 깊이)를 고려하여 바닥판보수공사(TYPE A, B, C) 선정절차를 제안하였다. It is imperative to propose effective maintenance strategies for deteriorated bridge concrete deck, given the increasing cases of maintenance failures. This study aims to elucidate the deterioration mechanism and patterns of bridge concrete deck degradation. Additionally, it presents various repair methods and flowcharts for determining the most suitable repair method for each type of deterioration. The deterioration mechanisms include initial defects, cracks, heavy vehicle loads, and the infiltration of water and deicing chemicals through cracks. These factors lead to the expansion and deepening of deterioration, exacerbated by freeze-thaw cycles and heavy vehicles. Repair methods are categorized into concrete overlay repair (Type A), partial-depth deck repair (Type B), and full-depth deck repair (Type C). The study also proposes flowcharts for determining the appropriate repair method based on results obtained from visual and in-depth inspections of deteriorated concrete decks. By following this structured approach, the maintenance and rehabilitation of bridge decks can be conducted more efficiently, reducing long-term costs and enhancing the resilience of bridge infrastructure.

Delamination and concrete quality assessment of concrete bridge decks using a fully autonomous RABIT platform

Gucunski, Nenad,Kee, Seong-Hoon,La, Hung,Basily, Basily,Maher, Ali Techno-Press 2015 Structural monitoring and maintenance Vol.2 No.1

One of the main causes of a limited use of nondestructive evaluation (NDE) technologies in bridge deck assessment is the speed of data collection and analysis. The paper describes development and implementation of the RABIT (Robotics Assisted Bridge Inspection Tool) for data collection using multiple NDE technologies. The system is designed to characterize three most common deterioration types in concrete bridge decks: rebar corrosion, delamination, and concrete degradation. It implements four NDE technologies: electrical resistivity (ER), impact echo (IE), ground-penetrating radar (GPR), and ultrasonic surface waves (USW) method. The technologies are used in a complementary way to enhance the interpretation. In addition, the system utilizes advanced vision to complement traditional visual inspection. Finally, the RABIT collects data at a significantly higher speed than it is done using traditional NDE equipment. The robotic system is complemented by an advanced data interpretation. The associated platform for the enhanced interpretation of condition assessment in concrete bridge decks utilizes data integration, fusion, and deterioration and defect visualization. This paper concentrates on the validation and field implementation of two NDE technologies. The first one is IE used in the delamination detection and characterization, while the second one is the USW method used in the assessment of concrete quality. The validation of performance of the two methods was conducted on a 9 m long and 3.6 m wide fabricated bridge structure with numerous artificial defects embedded in the deck.

Evaluation of the Compatibility of Repair Materials for Concrete Structures

Giri Venkiteela,Matthew Klein,Husam Najm,Perumalsamy Naidu Balaguru 한국콘크리트학회 2017 International Journal of Concrete Structures and M Vol.11 No.3

This study evaluates the compatibility of repair materials for concrete bridge decks. A new compatibility test set-up was designed and tested based on the concrete bridge deck cracking and delamination mechanism theory. The repair materials used in this study include lab formulated inorganic nano-aluminum silicates and commercially available organic two-part epoxy systems. Two different lab test-setups are proposed in this study: a prototype and a full-scale test. The developed test procedures were effective in communicating results in terms of compatibility of material properties, performance and quality. The prototype beams test can successfully serve as a small scale screening test providing insights on materials selection for the full-scale beam tests. The full-scale beams demonstrated the compatibility of the repaired system by providing data on authentic field conditions. Based on the observations it can be concluded that the proposed test setup is effective in examining the concrete bridge deck repair materials performance and selection, and compatibility in terms of mechanical properties and further guarantee the repaired structure safety.