• 한국도로학회논문집
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• 제16권5호
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• pp.39-47
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• 2014

PURPOSES : This study aimed to analyze economic effect of recycled aggregate production on job-site airport pavement. METHODS : The validation of site recycling for waste concrete as economic efficiency is analyzed through the case study of site recycling at an O airport pavement construction. The break-even point for the cost of site recycling was estimated according to two different waste concrete processing methods such as job-site recycling and processing on commission (or plant). RESULTS : Job-site recycling cost decreases as the use rate of job-site recycled concrete aggregate increases, or the amount of concrete waste increases, but transporting distance decreases. It was shown in an O airport case that as the use rate of job-site recycled concrete aggregate exceeds 61.4 %, the job-site recycling cost is cheaper than the processing cost on commission. CONCLUSIONS : The results of this study can utilize basic data of feasibility for site recycling of waste concrete on airport pavement construction.

• 한국산학기술학회논문지
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• 제1권2호
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• pp.75-83
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• 2000

최근 경제성장 및 국민 생활향상에 따라 폐기물 발생량이 급격하게 증대되어 그 처리문제가 심각해지고 있다. 이러한 폐기물중 노고 포장의 해체 및 유지·보수공사의 증가에 따라 다량 발생하고 있는 폐아스콘은 대부분 재활용되지 못하고 불법처분 또는 매립되고 있어 자원낭비 및 심각한 환경오염 문제를 야기하고 있는 실정이다. 따라서 본 연구에서는 폐아스콘의 재활용을 촉진하기 위하여 이동형 아스팔트 재생기 및 재생첨가제를 사용하여 양질의 신재 아스콘과 동등 수준의 품질을 갖춘 기층용 재생아스콘을 제조하기 위한 기초적 연구를 수행하였다.

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.2019-2024
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• 2021

For evaluating the radiological safety of dismantled concrete, the process of disposal and recycling of the radioactive concrete generated during the dismantling of Kori Unit 1 is analyzed. Four scenarios are derived based on the analysis of the concrete recycling and disposal process, and the potential exposure to the workers and public during this process are calculated. VISIPLAN and RESRAD code are used for evaluating the dosages received by the workers and public in the following four scenarios: concrete inspection, transport of concrete by the truck driver, driving on a recycled concrete road, and public living near the landfilled concrete waste. Two worker exposure scenarios in the processing of concrete and two public exposure scenarios in recycling and disposal are considered; in all the scenarios, the exposure dose does not exceed the annual dose limit for each representative.

• 한국안전학회지
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• 제29권4호
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• pp.123-131
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• 2014

Whole amount of waste water, approximately 921.6 liter, for cleaning a ready mixed concrete truck should be used to produce concrete as a mixing water or cleaning water. Recycling water for concrete mixing contains solids, which cause decrease in slump, air and compressive strengths, so it may influence on poor concrete quality. Therefore, it has been maintained to use recycling water with less than 3 percent of solids. Since no evaluation system has been constructed to directly reflect on variability of recycling water from ready mixed concrete plants, it is necessary to develop "Automatic recycling solid measuring system" for quality controls in real time. In this research, sensors measuring waste water concentration in ultrasonic and inductance methods were developed, and automatic system using the sensors were established. The accuracy of measurement sensors developed for recycling water based on various conditions of concentration was proved, and application limits were evaluated. Also, concentration of recycling water using sensors developed from ready mixed concrete plant was measured, and curing method verified the accuracy of the sensors. Moreover, measurement sensors for recycling water in various locations were installed to evaluate the effects on measuring method and spots. The automatic measuring system for recycling water concentration, which is developed in the research, will contribute to improve concrete quality safety through reliable solids maintenance.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.561-566
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• 1999

Due to recent demolition works of aged concrete bridges and buildings, a considerable amount of waste concrete material have been reclaimed without crushing works. It is well believed that waste concrete could be used for recycling good coarse aggregate, which could contribute to partly reduce environmental pollutions due to noise and dust by demolition works, and also to solve the shortage of natural aggregate for new concrete works. This experimental study is to investigate the flexural and shear behaviour of recycling RC beams with pertinent amount of recycling coarse aggregate, such as 30%, 50% and 100% of total aggregate volume. It is concluded from the test that structural behaviour of recycled concrete is determined to have similar behaviour of normal concrete.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.530-545
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• 2023

As an alternative to conventional management options for a lot of concrete waste from decommissioning of nuclear power plants, a set of scenarios for controlled recycling of decommissioning concrete waste as engineered barriers of a radioactive waste repository was proposed, and a comprehensive safety assessment model and framework covering both pre-and post-closure phases was newly developed. The new methodology was applied to a reference vault-type repository, and the ratios of derived concentration limits to unconditional clearance levels of eighteen radionuclides for controlled recycling were provided for three sets of dose criteria (0.01, 1, and 20 mSv/y for the pre-closure and 0.01 mSv/y for the post-closure phases). It turns out that decommissioning concrete waste whose concentration is much higher than the unconditional clearance level can be recycled even when the dose criterion 0.01 mSv/y is applied. Moreover, a case study on ABWR bio-shield shows that the fraction of recyclable concrete waste increases significantly by increasing the dose criterion for the radiation worker in the pre-closure phase or the duration of storage prior to recycling. The results of this study are expected to contribute to demonstrating the feasibility of controlled recycling of a lot of decommissioning concrete waste within nuclear sectors.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.327-328
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• 2021

In the manufacturing process of ready-mixed concrete, quantity management directly affects the workability and strength of concrete. Therefore, water quantity is the most important management factor for water quality control of ready-mixed concrete. It can be said that the number of unit water in the mix design, the water quantity due to the surface water contained in the aggregate used, and the water quantity taking into account the concentration of sludge contained in the recycling water when using the recycling water are factors that affect the quantity management of ready-mixed concrete. In this study, as a stable quality control method of ready-mixed concrete, a quantity management method by aggregate surface water and a sludge concentration management method according to the use of recycling water were proposed. Thus, we tried to suggest an efficient quantity management method for stabilizing the quality of ready-mixed concrete.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2003년도 추계정기총회 및 국제심포지엄
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• pp.129-133
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• 2003

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.777-780
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• 2008

레미콘공장에서 발생되는 회수수는 대부분 재활용되고 있으나, 회수수 슬러지에는 시멘트, 골재, 혼화제 등이 포함되어 있어, 콘크리트 제조시 성능을 저하시키는 요인으로 작용하고 있다. 본 연구에서는 회수수에 포함되어 있는 슬러지를 콘크리트용 혼화재료로서 활용하고자 기존의 연구를 참고하여 슬러지를 하소하여 활성도를 부여하였다. 활성도를 부여한 슬러지를 콘크리트용 혼화재로 사용한 특성을 분석하기 위하여 기본배합을 고로슬래그 미분말 대체, 플라이애시 대체, 고로슬래그 미분말과 플라이애시를 혼합 대체한 3가지 수준으로 하였으며, 기본배합에 대하여 활성 슬러지를 결합재의 2.5%씩 12.5%까지 대체하였다. 그 결과, 슬러지 대체율이 증가할수록 슬럼프는 다소 감소하였으며, 공기량은 증가하였으나, 큰 변화는 보이지 않았다. 콘크리트의 압축강도는 슬러지의 대체율 증가에 따라 소폭으로 증가하는 경향이었다. 이러한 결과를 바탕으로 레미콘 공장에서 발생되는 회수수 슬러지에 활성도를 부여하면 콘크리트 품질에는 큰 변화가 없을 것으로 판단되며, 회수수의 슬러지 농도를 저감시켜 레미콘 품질향상에도 기여할 것으로 전망된다.

• 한국산학기술학회논문지
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• 제2권2호
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• pp.65-71
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• 2001

폐아스팔트혼합물의 배출은 좁은 도로와 늘어나는 교통량에 의해 해마다 그 양이 증가하고 있으며 건설폐기물 중에 그 오염도가 다른 폐기물에 비하여 매우 심각하다고 할 수 있다. 특히 폐아스팔트혼합물의 경우 단순히 환경오염 차원을 넘어 무단 투기되므로 국민의 식수원을 오염시켜 사회적 문제로 대두되고 있는 실정으로 국내의 실정을 감안할 때 천연자원의 보존, 막대한 처리비용 절감 및 환경보전이라는 측면에서도 막대한 양의 폐아스팔트혼합물에 대하여 가열 및 상온 아스팔트재활용과 처리에 대한 중요성을 실감할 수가 있다. 본 연구에서는 가열의 공정을 생략하고 이러한 단점들을 제거하여 폐아스팔트혼합물의 재활용 취지에 좀더 가까운 결과를 유도할 수 있는 상온 아스팔트 재활용에 관하여 상온재활용 및 처리기술의 개발 및 상온재생 방법의 실험적인 연구를 통하여 그 적용성 및 적합성을 검토하고자 한다.