• 한국구조물진단유지관리공학회 논문집
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• 제21권5호
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• pp.67-73
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• 2017

고속도로에서 콘크리트 포장의 알칼리-골재반응 발생 구간이 증가하고 있다. 알칼리-골재반응이 발생한 콘크리트 포장은 팽창하면서 인접 교량에 교대 변위를 발생시켜 다수의 손상을 발생시키고 있다. 현장 조사 결과 콘크리트 포장의 팽창량은 온도 신축에 의한 팽창률을 상회하면서 교량에 치명적인 하중으로 작용하고 있어 손상 방지를 위한 선제적인 조치가 필요하다. 알칼리-골재 반응에 의한 팽창 정도는알칼리-골재반응의 상태, 포장의 길이 및 도로구조에 따라 달라짐을 알 수 있었다. 교량의 손상 방지를 위해선 콘크리트 포장의 팽창력을 이완시켜 주는 방안이 효과적이며 콘크리트 포장의 길이가 긴 구간은 아스팔트 치환공법이 유리할 것이다.

• 한국도로학회논문집
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• 제19권1호
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• pp.37-44
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• 2017

PURPOSES : This study is primarily focused on evaluating the effects of the non-linear stress-strain behavior of RAP concrete on structural response characteristics as is applicable to concrete pavement. METHODS : A 3D FE model was developed by incorporating the actual stress-strain behavior of RAP concrete obtained via flexural strength testing as a material property model to evaluate the effects of the non-linear stress-strain behavior to failure on the maximum stresses in the concrete slab and potential performance prediction results. In addition, a typical linear elastic model was employed to analyze the structural responses for comparison purposes. The analytical results from the FE model incorporating the actual stress-strain behavior of RAP concrete were compared to the corresponding results from the linear elastic FE model. RESULTS : The results indicate that the linear elastic model tends to yield higher predicted maximum stresses in the concrete as compared to those obtained via the actual stress-strain model. Consequently, these higher predicted stresses lead to a difference in potential performance of the concrete pavement containing RAP. CONCLUSIONS : Analysis of the concrete pavement containing RAP demonstrated that an appropriate analytical model using the actual stress-strain characteristics should be employed to calculate the structural responses of RAP concrete pavement instead of simply assuming the concrete to be a linear elastic material.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1989년도 가을 학술발표회 논문집
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• pp.43-47
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• 1989

In recent years, it has been found that one of the most significant factors in the reduction of the life of concrete pavements is the presence of voids beneath the slab. In the design of pavement, it is assumed that there is a full support through the length of the pavement. When a void develops, this assumption is no longer vaild. With increasing void size, traffic loads have a very a significant increase in stress. Thus, the combination of existing voids and increasing traffic loads results in significant pavement life reduction. Basea on the results of an experimental deflection using Dynaflect device and a theoretical one on the pavement model, this study presents a rational evaluation technique for detecting voids beneath the plain reinforced concrete pavement.

• 콘크리트학회논문집
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• 제25권1호
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• pp.11-18
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• 2013

시멘트 콘크리트 포장은 중차량에 대한 뛰어난 적용성과 장기간의 공용성을 지녔고, 아스팔트보다 구입이 용이하여 내구성 및 경제적 측면에서 우수한 장점을 가지고 있으나, 아스팔트 포장에 비해 노후화 되거나 파손이 발생할 경우 대규모 유지보수가 발생할 수 있는 단점이 있다. 콘크리트 포장의 손상은 대부분 균열에 의한 것으로 콘크리트 포장의 초기 및 장기균열을 제어할 수 있는 기술 확보가 필요하다. 이 연구에서는 일반적인 구조용 콘크리트 배합에 비해 단위수량이 낮고 굵은 골재 최대 치수가 큰 콘크리트 포장 배합에서의 섬유보강 효과를 평가하기 위해 직경이 작고 형상비가 큰 마이크로 섬유와 직경이 크고 형상비가 작은 매크로 섬유로 하이브리드 보강된 콘크리트 포장용 배합에 대한 기본적인 성능실험을 수행하였다. 실험 결과 콘크리트 포장 배합의 섬유보강 효과는 일반 구조용 콘크리트 배합에 비해 낮은 것으로 나타났으나 하이브리드 섬유로 보강된 콘크리트 포장 배합은 휨강도 및 인성보강 효과가 큰 것으로 나타났다. 특히 하이브리드 섬유보강 콘크리트는 포장 손상의 주요 요인인 콘크리트 포장의 초기 건조수축을 제어하는데 매우 효과적인 것으로 나타났다.

• 한국농공학회논문집
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• 제57권2호
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• pp.47-56
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• 2015

At the present, the mechanized form roads pavement was constructed with plain concrete. Mostly, it was used by welded wire mesh for preventing crack. Cellulose fibers for the reinforcement of concrete offer relatively high levels of elastic modulus, fiber count (per unit weight), specific surface, and bond strength to cement-based materials. The construction of concrete pavement confirmed that cellulose fiber reinforced concrete was applicable to mechanized form roads pavement. In the study, cellulose fibers were used here at 0.08 % volume fraction, which is equivalent to a fiber content of $1.2kg/m^3$. Cellulose fiber reinforced concrete were compared with plain concrete. Field test results indicated that cellulose fiber reinforced concrete showed slightly to increase of 28 days compressive strength and improved the initial strength. it tended to increase of splitting tensile strength. Test results showed that the slump and air content tend to decreased. but, the variation of air contends is very little. Also, construction cost of cellulose fiber reinforced concrete is less than about 25.7 % the case of welded wire mesh previously used. Therefore, The cost reduction is expected to be possible in construction site by mechanized form roads pavement.

• International Journal of Concrete Structures and Materials
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• 제18권3E호
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• pp.145-150
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• 2006

An experiment with the objective of providing guidelines for joint depth determination and timing of contraction joint sawcutting to avert uncontrolled cement concrete pavement cracking has been conducted. Theoretical analysis and laboratory tests were performed to help in understanding and analyzing the field observation. Using two-dimensional elastic fracture mechanics, the influence of several parameters on crack propagation was delineated by a parametric study, involving initial notch ratio, joint spacing, Young's modulus and thermal expansion coefficient of concrete, temperature gradient, and modulus of subgrade reaction. Bimaterials made of rock plus cement mortar and rock plus polymer mortar were applied to the concrete in a field test section, and they were subjected to fracture tests. These tests have shown that fracture mechanics is a powerful tool not only in judging the quality of the jointed cement concrete pavement but also in providing a criterion for crack propagation and delamination. Based on fracture mechanics, a method is proposed to determine the joint depth, sawcut timing, and spacing of the jointed cement concrete pavement. This method has successfully been applied to a test section in Seohaean expressway. This study also summarizes the research results obtained from a field test for jointed plain concrete pavement, which was also carried out on the Seohaean expressway.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.533-538
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• 1999

Nowadays, as the traffic volume is higher, the more pavement are expanded and constructed. In korea, the most of the pavement system were covered with an asphaltic concrete or portland cement concrete, so it need the new system of pavement to protect the natural environments. The objectives of this study are to investigate properties and applications of soilcrete using FGC soil stabilizer and then to evaluate the benefits to be gained by soilcrete pavement, when a pavement system of existing are replaced by soilcrete. for example, environmental advantages, cost savings, ultimately.

• 한국도로학회논문집
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• 제19권3호
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• pp.11-18
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• 2017

PURPOSES : This study investigates the effect on concrete pavement accordance with the curing methods in cool weather and supports the best method in the field. METHODS : Two field tests evaluated the curing methods of concrete pavement in cool weather. Firstly, five curing methods were tested, including normal curing compound, black curing compound, bubble sheet, curing mat, and curing mat covered with vinyl. Concrete maturity was compared from temperature data. Secondly, normal curing compound and curing mat with vinyl, which showed the best performance, were compared in terms of maturity and join condition index. RESULTS:From the field tests, it is an evident that curing mat with vinyl accelerated the concrete strength. Therefore, it is possible to conduct saw-cut works in cool weather, which minimizes damage on concrete at joint. CONCLUSIONS : For concrete pavement in cool weather, using curing mat with vinyl as the curing method could overcome the strength delay. Therefore, strength and durability problems on concrete at joint due to cool weather would be fewer in the future.

• 대한토목학회논문집
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• 제31권4D호
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• pp.555-564
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• 2011

국내 고속도로의 60% 이상이 시멘트 콘크리트 포장으로 건설되었으며, 그 중 공용년수가 20년이 넘어선 구간이 절반이상에 달하고 있다. 노후화 된 콘크리트 포장의 보수 보강은 국내의 교통여건상 우회도로가 준비되기 어렵기 때문에 조기교통개방이 요구되며 현재까지는 주로 아스팔트 덧씌우기가 사용되고 있다. 그러나 아스팔트 덧씌우기 포장은 보수 후 수년만에 발생하는 조기 파손이 빈번하여 많은 유지보수비용이 지출될 뿐 아니라 도로사용자의 불편을 초래하고 있다. 최근 들어 노후화 된 콘크리트 포장의 효율적인 보강공법으로 접착식 콘크리트 덧씌우기 공법의 적용이 시도되고 있다. 따라서 어떠한 인자가 접착식 콘크리트 덧씌우기의 수명에 영향을 미치는 지 고찰할 필요가 있다. 국내에서는 콘크리트 덧씌우기 포장의 공용 중 파손상태에 대한 자료가 미비한 실정이다. 본 연구에서는 접착식 콘크리트 덧씌우기 수명과 영향인자간의 상관성을 검토하기 위해 다양한 파손자료를 구축하고 있는 미국의 LTPP data를 이용하여 각 구간의 포장단면, 교통량 및 환경특성을 고려하여 포장의 연도별 파손에 대한 database를 구축하였다. 또한 각 구간의 포장수명을 산정 후 접착식 콘크리트 덧씌우기 구간의 수명과 이에 영향을 미치는 인자들에 대해서 통계분석을 수행하였다.

• 농업과학연구
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• 제37권2호
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• pp.277-283
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• 2010

Research on permeable pavement like asphalt and concrete pavement with porous structure has been increasing due to environmental and functional need such as reduction of run off and flood. This study was performed to evaluate void ratio, permeability coefficient, and compressive strength of permeable polymer concrete (PPC) using crushed and recycled coarse aggregate that is obtained from waste concrete. Also, 6 mm length of polypropylene fiber was used to increase toughness and interlocking between aggregate and aggregate surrounded by binder. Binder and filler used were unsaturated polyester resin and CaCO3, respectively. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate sizes 5~10 mm. In the test results, regardless of kinds of aggregates and fiber contents, the void ratio, permeability coefficient and compressive strength of all types of PPC showed the higher than the criterion of porous concrete that is used in permeable pavement in Korea. Also, strengths of PPC with increase polypropylene fiber volume fraction showed slightly increased tendency due to increase binder with increase of fiber volume fraction. Accordingly, polypropylene fiber and recycled coarse aggregate can be used for permeable pavement.