• International Journal of Concrete Structures and Materials
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• 제9권2호
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• pp.219-239
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• 2015

This paper discusses the suitability of producing concrete with 100 % recycled aggregate to meet durability and strength requirements for different applications. Aggregate strength, gradation, absorption, specific gravity, shape and texture are some of the physical and mechanical characteristics that contribute to the strength and durability of concrete. In general, the quality of recycled aggregate depends on the loading and exposure conditions of the demolished structures. Therefore, the experimental program was focused on the evaluation of physical and mechanical properties of the recycled aggregate over a period of 6 months. In addition, concrete properties produced with fine and coarse recycled aggregate were evaluated. Several concrete mixes were prepared with 100 % recycled aggregates and the results were compared to that of a control mix. SEM was conducted to examine the microstructure of selected mixes. The results showed that concrete with acceptable strength and durability could be produced if high packing density is achieved.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.259-266
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• 2008

Recently, the maintenance period of sidewalk pavement proposed in Ministry of Construction & Transportation to be extended by more than 10 years. Therefore it takes many interests in Durability and the maintenance. Beside sidewalk pavement, block pavement happened problems in parking and road less than 20km/hr about bearing capacity and durability, the maintenance. It interests about importance of environmentally friendly sidewalk pavement. It compared engineering characteristics about strength and durability through general pavement comparison with stone block pavement. It estimate bearing capacity in actual si-tu site and test site. It experimented plate bearing test and field density test. It verified about durability of pavement by construction availability of geosynthetics that is constructed by purpose of filter. Stone block pavement evaluated about application of sidewalk/road pavement on the basis of result.

• 대한건축학회논문집:구조계
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• 제34권2호
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• pp.41-48
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• 2018

Carbonation is one of the major detrimental factors to the reinforced concrete structures owing to penetration of atmospheric CO2 through the micro pores, thereby it reduces the durability of the concrete. The maintenance periods and cost for concrete according to the coefficient variation of different finishing materials is documented in literature. However, it is required to carry out the systematic and well planned studies. Therefore, keeping them in mind, surface repair was carried out to the carbonated concrete and the maintenance cost was calculated to measure the durability life after repair with different variable. The deterministic and probabilistic methods were applied for durability and repair cost of the concrete. In the existing deterministic model, the cost of repair materials increases significantly when the concrete structure reaches its service life. In present study using a stochastic model, the maintenance period and cost was evaluated. According to obtained results, there was no significant difference in the number of maintenance of the coefficient variation. The initial durability has a great influence on the maintenance time and cost of the structure. Unlike the deterministic model, the probabilistic cost estimating model reduces the number of maintenance to the target service life expectancy.

• 동력기계공학회지
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• 제18권2호
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• pp.43-49
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• 2014

This study has been investigated on the durability of carbon fiber/epoxy composites (CFRP) in moisture environment. The carbon fiber/epoxy composites were modified to use the nanoparticles such as carbon nanotubes and titanium oxide. These hybrid composites were exposed to moisture environment for a certain period of time. Weight gain according to immersion time, quasi-static tensile test and micro-graphic characterization were investigated on the samples exposed to moisture environment. Consequently, the weight gains increased with increasing immersion time and weight gain of the hybrid composites was lower than the one of CFRP through the whole immersion time. The tensile strengths decreased with increasing immersion time and tensile strengths of the hybrid composites were higher than the one of CFRP through the whole immersion time. The CFRP were observed more degraded than hybrid compositess in moisture environment. Therefore, it was concluded that the addition of nanoparticles in CFRP could lead to improve the durability in moisture environment.

• 한국농공학회논문집
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• 제49권4호
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• pp.35-41
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• 2007

The most agricultural concrete structures for the irrigation and drainage are exposed to the underwater condition at the irrigation period and they take the influence on very severe cold in the winter. Therefore, it is impossible to use repair materials used to the general concrete structures. The research need the development of the repair material for a performance enhance of the agricultural underwater concrete structures. This research evaluated the mechanical and durability performance of the latex modified repair mortar for underwater concrete structures which peformed the repair in the underwater according to the characteristic of the agricultural concrete structure. The latex modified repair mortar is a material that minimize the effect of the ecosystem, environment and the segregation. In this research, the construction condition of the latex modified repair mortar for agricultural concrete structures was considered and the test specimens made in the underwater condition. Test results was then compared with target performance and commercial repair mortar. Experimental test results indicated that the mechanical and durability performance of latex modified repair mortar for agricultural underwater concrete structure satisfied all target performance. Also, the latex modified repair mortar resulted in better repair performance than the commercial repair mortar.

• 한국해양공학회지
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• 제28권1호
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• pp.64-68
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• 2014

This study was conducted to investigate the durability of carbon fiber/epoxy composites (CFRP) in a saline water environment. The carbon fiber/epoxy composites were modified to use nanoparticles such as carbon nanotubes and titanum oxide. These hybrid composites were exposed to a saline water environment for a certain period. The weight gain according to the immersion time, a quasi-static tensile test, and micro-graphic characterization were used to investigate the samples exposed to the saline water environment. The weight gains increased with increasing immersion time. The weight gains of the hybrid composites were lower than that for pure CFRP throughout the entire immersion time. The tensile strengths decreased with increasing immersion time. The tensile strengths of the hybrid composites were higher than that of the pure CFRP throughout the entire immersion time. The pure CFRP was observed to be more degraded than the hybrid composites in the saline water environment. Therefore, it was concluded that the addition of nanoparticles to CFRP could lead to improved durability in a saline water environment.

• 한국재난정보학회 논문집
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• 제15권1호
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• pp.28-38
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• 2019

연구목적: 본 연구는 건설 계측센서의 내구연한 저하원인 및 개선방안을 상세히 제시하여 건설구조물의 계측관리 수준향상과 계측센서의 기술발전에 기여하고자 한다. 연구방법: 건설 계측센서의 내구연한 저하원인 및 개선방안에 대하여 건설분야와 전기전자분야로 구분하여 상세한 현황을 조사하고 검토를 실시하였다. 연구결과: 건설분야는 승인 및 검수, 검사 및 시험, 검정 및 교정, 손망실율 최소화 방안 등을 조사 검토하였고, 전기전자분야는 센서패키지 및 실링, 응력집중부위 단선, 낙뢰 및 부식에 의한 손상 등을 조사 검토하였다. 결론: 건설분야와 전기전자분야에서 계측센서의 내구연한 저하원인 및 개선방안을 토대로 건설현장에 적용되는 계측센서의 내구연한이 현재보다 연장될 것으로 기대된다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.326-331
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• 2006

The durability of recent motors is longer than the past one because there are the rapid technique development of the automobile industry and the vehicle maintenance of users. And then the importance of the durability test due to vibration is increased from day to day. So full vehicle and parts companies accomplish the durability test using various methods. The most public test method among them is the reliable field test but it bring on higher cost and period of the development process. The durability test using MAST(multi axis simulation table) is a solution in order to improve the development process of automobiles. Generally its excitation source uses the optimized road profiles that are obtained by the road test of belgian road, country road, cobbleston road and so on instead of a real field but the interrelations and influences accordingly vehicle damage are considered by a field test between specific roads and real fields in the first place. Therefore this study, in order to accomplish a basic research for the durability test using the MAST, performed on the real field driving test at various domestic roads and the results which are analyzed by PSD(power spectrum density) are compared with relative sensitivity among the roads. Consequently they can present a basic material for generation of road profiles which is applied to the durability test using MAST.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.169-172
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• 2002

In this study, the effects of the number of coat and immersion period on strength properties, waterproofness and chemical resistance of painted and immersed cement mortars using two admixture were examined. Test results showed that the flexural and the compressive strengths of the coated and immersed cement mortars increase with increasing number of coat and immersion period. The water absorption of the coated and immersed cement mortars tended to decrease with increasing number of coated and immersion period. In the case of the change of weight and the immersion period for the solutions, a decreasing tendency was shown as the immersion period increases regardless of solution, with a little variation.

• 한국터널지하공간학회 논문집
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• 제20권1호
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• pp.73-81
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• 2018

본 논문은 지하구조물 계측센서의 내구연한 기준에 대한 규정 분석 연구로 국내 건설공사 발주기관의 건설 계측센서에 대한 내구연한 기준을 조사 분석하고, 법인세 시행규칙에서 건축물 등의 기준 내용연수 및 조달청의 건설계측 및 건설기계 관련 내용연수 기준을 분석하였다. 지하 구조물에 설치되기 전 조달청에서 물품 자체로 구매하는 경사계와 변형률계 등의 내구연한 기준은 8년에서 10년을 제시하고 있으나, 건설공사 시 원 지반 및 콘크리트 구조물 내에 설치된 계측센서는 지하수 영향 및 다짐 등 여러 가지 불리한 요인으로 물품 자체의 내용연수보다는 상당 기간 단축될 것으로 판단된다.