In this study, the recycling processes of construction and demolition waste (C&D waste) were analyzed, and its national recycling rate was determined using material flow analysis (MFA). Available statistical data provided by Ministry of Environment and Korea Environment Corporation were used for the MFA study. The collected data were carefully examined and validated by field investigations. System boundary for MFA covered from waste generation from construction sites to final disposal in 2013. The field investigation showed that recycled aggregate is produced through mechanical shredding, separation, and screening processes of C&D waste. The production efficiency (or process yield) was estimated to be approximately 81.2% on average. The foreign materials in the waste accounted for 18.8% by weight. The separated impurities were sent to recycling facilities, incineration facilities, or landfill sites, depending on the physicochemical characteristics. Efficiency of recycling facilities and the statistical data were integrated to estimate the national actual recycling rate, which turned out to be 87.7% in 2013. Approximately 49.1% of the construction-related waste was recycled as recycled aggregate for concrete production and road base layer for asphalt pavement. Based on the result of MFA, there is 9.8% difference between the actual recycling rate in this study and reported recycling rate by national statistics. In the future, more various C&D waste treatment and disposal facilities, along with aggregate recycling facility, should be investigated to verify the actual recycling rate determined by this study. Statistical accuracy should be further refined through additional field investigations. Our findings can be applicable to development of recycling policies and best management practices for C&D waste streams.

This study includes research works to develop high performance concrete or cementitious composite with PE fiber, using stone dust sludge or LCD waste glass.

In this study, the specific 3-dimensional plant model is developed to check the physical interference of structures and components which cross each other, and to reduce the interference errors occurred between interconnecting parts. Based on 3D model, the construction schedule is reviewed by 4D simulation to avoid construction activity overlapping. Also, the layout simulation of a large capacity crane is implemented to relieve interference on the run-time of a large capacity crane.

The current study is a basic research to review the possibility of using steel wire from waste tires as recycled steel fiber for construction purposes. It analyzes preexisting waste tire-related data before processing and selecting waste steel wires to compare their composition and three quality standards if appearance as defined by concrete steel fiber regulations (KS F 2564), tensile strength, and flexibility, in order to review the feasibility of reusing waste steel wires. The results showed that the waste steel wires satisfy quality standards stated in the concrete steel fiber regulation (KS F 2564), indicating that they may be reused as recycled steel fiber for concrete.

In this study we were to explore the seasonal variation of water temperature distributions before and after weir construction at Gumi, Chilgok, Gangjung(Goryung), Dalsung in the Nakdong River using Landsat satellite images. Relationship between in-situ water temperature and radiance values of Landsat-5, 7, 8 satellite images showed high correlation. Seasonal variation of water temperature in Nakdong River showed that the fluctuation ranges of water temperature before weir construction were larger than those after weir construction. This indicated that the variation of water temperature is due to the difference of heat storage volume by weir construction and dredging work. In particular, the water temperature after weirs construction in autumn was 4-8 times lower than that before weirs construction. Water temperature after weir construction decreased in spring and summer at the downstream of Gumi weir and Gangjung(Goryung) weir, and the upstream of Dalsung weir. In autumn and winter, the water temperature after weir construction increased in the upstream and downstream of the whole weirs except upstream of Gumi weir. Relationship between water temperature and meteorological elements (air temperature, wind speed, sunshine, radiation) showed high correlation of above 94% in air temperature, and then radiation was high correlation before and after 65%.

최근 전 세계적으로 환경오염이나 자원고갈이 급속히 진전되는 가운데, 건설 산업은 타 산업의 생산 활동에 비해 막대한 자원소비와 대량의 폐기물 배출 문제를 야기함으로써 지구의 환경부하를 증대시키는 주요 원인이 되고 있다. 특히 건설폐기물의 발생량은 1995년 국가통계가 기록된 이후 지속적으로 증가해왔으며, 그 양은 국가에서 발생하는 폐기물의 약 50%를 점유하는 수준(2013년 약 66,991,261톤)으로 이러한 추세는 앞으로도 지속될 것으로 예상된다. 국내에서는 이러한 건설폐기물의 적정 관리방안 마련을 위하여 다각적 측면의 검토 및 연구가 진행되어 왔다. 건설폐기물은 처리 지침에 따라 종류별, 처리방법별 분리배출 하여 재활용을 우선적 처리방법으로 하도록 하고 있다. 최근 2013년 국가 통계상 건설폐기물의 재활용률은 97.5%로 나타났다. 하지만 국가 통계상 재활용량은 재활용 시설로 반입되는 폐기물의 양을 나타내며, 공정에서 발생하는 이물질, 부산물, 손실량 등을 고려하지 않은 데이터 이다. 이처럼 국가 통계데이터는 현실적 요소를 반영하지 못하고 있어 실질적인 처리현황으로 판단하기에는 다소 한계가 있다. 이러한 문제점을 해결하고 국가 차원의 재활용 질적 수준과 현황파악을 위해서는 보다 현실성이 반영된 정보가 필요하며, 이러한 측면에서 재활용 시설의 공정파악과 물질흐름분석을 통한 기초자료의 구축이 매우 중요하다. 따라서 본 연구에서는 건설폐기물의 처리 공정 특성을 파악하고, 전과정 단계에 따른 물질흐름분석을 통하여 국가수준의 실질 재활용률을 산정하였다. 본 연구에서는 환경부, 한국환경공단 등의 통계데이터를 활용하였으며, 또한 건설폐기물 재활용시설 현장 실태조사를 통하여 통계 데이터를 검증하고 물질흐름분석 위한 기초 데이터를 수집하였다. 물질흐름분석의 시스템경계는 건설현장에서의 건설폐기물 발생단계부터 최종 처분단계까지를 포함하였으며, 시간적 범위는 2013년 연간 데이터를 활용하였다. 건설폐기물 재활용시설 실태조사 결과 반입되는 건설폐기물은 파쇄･분쇄 및 선별단계를 거쳐 순환골재로 생산되며 처리 공정의 순환골재 생산 수율은 약 83.7% 수준으로 산정되었다. 한편 반입량의 약 16.3%가 이물질로 선별되었으며, 그중 폐합성수지가 반입량의 약 8.43%로 가장 많은 비율을 차지하였다. 선별된 이물질은 각각 성상에 따라 재활용, 소각, 매립으로 배출되는 것으로 나타났다. 이러한 재활용시설의 공정수율과 국가 통계자료를 종합한 국가수준의 건설폐기물 실질재활용률 산정 결과 건설폐기물 발생량의 약 89%가 실질적으로 재활용되는 것으로 분석되었다. 또한 성토 및 복토용과 같은 저급용도(매립형 재활용)의 순환골재를 제외하면 발생량의 약 49.3%가 고급용도의 순환골재로써 재활용 되는 것으로 나타났다. 본 연구에서 실시한 물질흐름분석은 여러 가지 가정을 통하여 수행되었으며, 보다 정확한 건설폐기물 물질흐름분석의 수행을 위해 순환골재 생산시설 이외 다른 재활용 처리시설에 대한 조사가 필요하다. 본 연구의 결과는 건설폐기물 적정 관리를 위한 관련 정책 마련의 기초정보로 활용 될 수 있다.

TDFA (Tire Derived Fuel Ash) is byproduct after burning copped tire fillet in boiler. It contains relatively high SiO2 and CaO components with high Braine over 5,000g/cm3. Nowadays the reclamation site for TDFA is going insufficient and its utilization is strongly required. In the paper, its utilization for cement-based material is introduced. Its detailed strategy and test plans are presented in the related presentation.

Carbon nanotube(CNT), carbon nanotube-fiber(CNT-fiber) and graphene are representative nano materials which gained much attention by the research community owing to their excellent mechanical, electrical and heat conducting properties surpassing the existing materials by far. The utilization of these properties in construction materials is being actively studied. This paper summarizes the previous studies conducted by the authors regarding the utilization of nanotechnology into construction materials.

The study was conducted for making accident-free, accurate and effective construction site to improve the smart construction site management system by using new developed technology such as IoT, RFID, and etc... The study recommends new IoT construction management application and web with a structure of the system

It is required development on the work process of the legal system, quality management and safety management for safety securement of construction. Therefore, this study examines the status and issues surrounding the current legal systems and proposes improvements of material for safety securement of construction.

This study aims to suggest the available additional education courses that can be combined with the existing functional education, which is mainly for the enhancement of safety consciousness, along with a model for the way of management. To achieve the purpose of the study, the construction death accidents for the recent five years were analyzed about their patterns and the scales of the accident sites to infer the main subjects and the direction of hands-on education courses. Based on the analysis results, the recombination and management plans for the construction safety hands-on education courses and the additionally required education courses were proposed.

The purpose of this study is to analyse whether the capability assesment index to perform services as well as creditratings for the governmental procurement bidding influence earnings management behaviour using discretionary accrualsand real earnings management in the construction waste disposal industry. For this study, out of the 530 population(interimdisposal service companies for construction waste) across the country, the final sample of 144 companies is selected foran analysis period of six years, starting from 2008 to 2013. The modified Jones model (1995) is used to measure earningsmanagement and the Kothari et al. model (2005) reflecting return on total assets (ROA) is also applied to produce thediscretionary accruals. In addition, earnings management through real activities is measured by the model developed byRoychowdhury (2006) and the method developed by Cohen et al. (2008) is adopted to calculate the measurement ofintegration of real earnings management. Overall, our empirical results of the analysis show that the capability assessmentindex to perform services as well as credit ratings significantly influence earnings management behaviour in theconstruction waste disposal industry. First, the managers of companies having higher assessment index report increasedprofits through adjusting both discretionary accruals and real earings management. Second, the managers of speculativeenterprises which rank lower credit ratings use higher income-increasing discretionary accruals. These research findingsimply that the regulatory authorities should properly consider the earnings management behavior of the construction wastedisposal service industry in setting the qualification standards for the governmental procurement bidding. The usefulnessof this study results can be highlighted by alerting the industry managers that improper earnings management practicesnot only decrease the successful bidding chances of the companies involved but also deteriorate long-term firm valuesin the market.

열악한 작업환경 때문에 수중항만공사를 기계화하려는 많은 노력들이 시도되고 있다. 본 논문은 수중항만공사 중 사석 고르기 작업을 수행하는 수중건설로봇에 대해 기술한다. 로봇의 블레이드는 울퉁불퉁한 지형에서도 사석 마운드를 기준면에 대해 평편하게 고르고, 다목적 암은 사석을 파고, 채울 수 있게 설계되었다. 본 연구는 로봇에 설치된 위치 및 방위 센서와 동기를 이루면서 주행과 스윙운동이 포함된 다목 적암과 블레이드의 기구학을 해석한다. 기준수심센서에 부여된 월드좌표에 대해서 블레이드와 다목적암의 위치와 방위를 나타내고, 기준면과 나란한 고르기 작업을 위한 형상을 찾는다. 고르기 작업을 위한 유압제어시스템을 개발하며, 로봇에 의한 육상 및 수중 사석 고르기 작업을 실시해 실험결과를 보인다. 로봇의 작업속도는 잠수부보다 8배 정도 빠르며 작업품질도 우수한 것으로 평가된다. 잠수부가 작업할 수 없는 대 수심에서는 효율성이 더 좋을 것으로 기대된다.

최근 건설폐기물의 발생량 급증과 함께 천연골재자원의 대체재로 폐기콘크리트를 활용한 재생골재의 사용에 국가․사회적인 관심이 집중되면서, 이에 대한 관리 및 적정처리에 대한 사회적 중요성이 대두되었으며, 향후 골재자원의 수급불균형 문제에 대비한 장기적 자원수급대책 등을 위하여 자원의 효율적 이용과 절약, 폐기물의 발생규제 및 재활용 촉진을 통한 환경보존 등에 대한 관심이 증가되고 있다. 골재수요는 건설 산업의 지속적인 증가에 힘입어 향후에도 꾸준하게 증가하여 연간 2억 m³ (약 3억 3천만톤) 이상의 수요가 지속적으로 발생할 것으로 예상되고 있으며, 국토교통부의 연도별 골재 채취 실적 자료에 의하면, 2002년의 경우 골재의 허가 채취량은 1억 1,900만 m³에 달하여 골재 수요량인 2억 1,700만 m³의 54.9%를 채취 허가량으로 공급한 것으로 나타나고 있어 부족분의 골재를 충당하기 위한 노력이 다각적으로 진행되고 있으며, 이러한 배경에서 재생골재의 필요성이 크게 대두되고 있다. 건설폐기물 중 발생하는 폐기콘크리트는 발생하는 양이 대규모로 공급 면에서 별 문제가 없고, 그 조성도 시멘트 모르타르와 골재의 비교적 단일 조성으로 되어 있어 파쇄 하여 재사용하여도 콘크리트 자체의 물성을 어느 정도 유지하기 때문에 재활용가치가 높은 것으로 평가되고 있다. 본 연구에서는 건설폐기물로 발생되는 폐콘크리트를 이용하여 레미콘업체 및 건설업체 등에서 사용할 수 있는 품질의 순환골재 생산기술을 개발하고자 하였다. 이를 위해 잔골재 회수 process 구축 및 물리적･열적 박리 기술 적용과 최적 운전조건을 도출하였다.

This paper aims to develop a wireless multi-sensing system for structural health monitoring of civil structures. This system is designed to measure all kinds of data--static and dynamic response, etc--from a multi-sensing data logger, and to transmit the measured data by means of a wireless real-time RF module, and to analyze the transmitted data for a health monitoring of structure. To test its validity, a FE analysis of a model cable-stayed bridge has been conducted for system identification. And a modal test of the model bridge has been also performed by both the proposed system and a cable based commercial measurement system(IOTech) for comparison. Based on those results, the proposed system was found to have an excellent capability of measuring and transmitting data from actual structure, and thus to be applicable to health monitoring of civil structures.

With the increase in the frequency of the seismic activity in the territory of Korean Peninsula, the demand for seismic performance evaluation of existing buildings has appeared as well. In this research, a public building built in 1970s is evaluated by the Korea Infrastructure Safety Corporation guideline. As a result, this existing public building is evaluated to satisfy the life safety (LS) and the collapse prevention(CP) performance level that the KBC2009 demands for.