• 한국도로학회논문집
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• 제7권1호
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• pp.11-20
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• 2005

본 연구는 재활용 아스팔트 혼합물의 역학적 특성과 재생혼합물 내 바인더의 대형분자(Large molecular size : LMS)와의 상관성을 조사하였다. 재생 혼합물은 여러 가지 혼합 방법으로 제작하여 역학적 강도 시험을 수행하였고 재생혼합물 내의 RAP 굵은골재(R), 매트릭스(M) 및 신규 굵은골재(V) 시료에 코팅된 바인더의 노화 상태를 gel-permeation chromatography(GPC)를 통해 조사하였다. 재생혼합물 내 바인더의 노화상태 분석을 위한 혼합물 제조에는 원형골재 (13mm 강자갈)가 굵은골재로 사용되었다. GPC를 통한 재생혼합물 내 바인더의 노화상태를 분석한 결과 신 구 바인더의 노화 정도에 차이를 확인했으며, 혼합 방법에 따라 재생혼합물의 바인더 노화 상태가 서로 상이함을 확인하였다. 역학적 강도 특성과 R, M, V시료의 LMS에 대한 상관성분석결과 재생혼합물의 역학적 특성이 혼합물 내의 재료 중 어느 특정 재료의 바인더 LMS와 더 밀접한 상관관계를 보였다. 또한 LMS가 어느 정도 증가될 때까지는 강도특성이 향상되나 LMS가 보다 더 커지면 강도성능이 저하되는 경향을 보여 혼합물 제조시 제대로 회복되지 못한 노화된 아스팔트가 향후 노화가 더욱 진행되면 재생혼합물의 강도 성능이 저하될 것으로 판단되었다.

• Advances in concrete construction
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• 제6권4호
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• pp.375-386
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• 2018

This experimental work aims at developing and investigating a lightened concrete by the addition of treated straws. The used formulation is based on that of an ordinary concrete which is composed of sand and gravel as the main aggregates. The properties of the straws are improved by using one of two treatments before their use: the hot water and bitumen. Henceforth, the main objective of this study is to assess the mechanical characteristics of different formulations with different compositions and treatments on straws. The obtained results have shown that the addition of straws improves its lightness property. However, it decreases the compressive and flexural strengths as well as decreases the modulus of elasticity and increases the dimensional variations. Set into comparison to the concrete with untreated straws, the treatment of straws by hot water or by bitumen improves most of the characteristics.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.177-182
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• 1995

Large-scaling recycling of demolished concrete will contribute not only to the solution of a growing waste disposal problem. it will also help to conserve natural resoures of sand and gravel and to secure future supply of reasonly priced aggregates for builiding and other construction purposes within large urban areas. because recycled aggregate particles consist of substaintial amount of relatively soft cement paste component, it is less resistant to mechanical actions. With this view in mind, to obtain a reference data for the development of recycling system and to a basic data the guideline of recycled aggregate concrete construction and mix design, this study deals with the comparative analysis of the workability and engineering properties of recycled aggregate concrete according to the factors, such as blending ratio of recycled aggregate with the natural aggregate, addition of flyash, water cement ration.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.256-261
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• 1995

Large-scaling recycling of demolished concrete will concrete will contribute not only to the solution of a growing waste disposal problem, it will also help to consweve natural resoures of sand and gravel and to secure future supply of reasonly priced aggregates for building and other construction purposes within large urban areas. Because recycled aggregate particles consits of substantial amount of relatively soft cement paste component, it is less resistant to mechanical actions. With this view in mind, to obtain a reference data for the development of recycling system and to a basic data the guiedline of recycled aggregate concrete construction and engineering properties of recycled aggregate concrete according to the factors, such as blending ratio of recyced aggregete with the natural aggregate, addition to the factors, such as blending ratio of recycled aggregete with the natural aggregate, addition of flyash, water coment ratio.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.573-580
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• 2003

In Taiwan there are 21 Municipal Solid Waste Incinerators (MSWI) built to treat 80% of the MSW nationwide. Approximately 2,000 tons of incineration ashes of municipal waste contain reaction ash and fly ash (3:1 by weight)will be produced daily, and this may cause a serious waste problem. According to EPA regulations, reaction ash and fly ash produced after incineration should be properly treated. Landfill capacity barely meets the general demands. More efficient actions should be planned and taken. The study found 'reclamation' should be the optimal solution to this problem. Only limited research and previous successful experiences are available among other countries. An incinerator in Northern Taiwan is chosen for this study to make environmental bricks from the reaction ash and fly ash. From the previous tests, the results of strength test were measured. From the previous test results, the fly ash products have not reached the desired strength; hence, reaction ash is chosen for further pilot study. In the experiment, incineration ashes, cement and gravel are mixed in the ratio of 1:1:1(by weight), to ground concretization aggregate and pelletization aggregate, the concrete products made from the aggregates were of the strength of 108 $kgf/cm^2$ and 142 $kgf/cm^2$ individually. For the purpose of making nonstructural walls which met the State Building Standards. In the study, 50 tons of concrete products was yielded from aggregate and environmental bricks. Further observation and supervision are recommended to ascertain the resource recycling and reclamation. EPA has planned to build three 'Recycling Plants' in northern, middle and southern Taiwan to develop efficient techniques to produce concrete products, sub-base course, soundproofing wall, gravel, artificial fishing reefs, tiles, drainage, bricks and etc. This experiment of the demonstrative plant solves the problem of the incineration ashes and opens another opportunity to reclaim them.

• 자원환경지질
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• 제56권6호
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• pp.871-885
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• 2023

2022년에는 약 1억 2,874만 m³ 의 골재가 채취되었다. 이 중 모래는 약 4,427만 m³, 자갈은 약 8,447만 m³ 이다. 허가채취는 약 5,334만 m³, 신고채취는 약 7,540만 m³ 이다. 골재원별로는 선별파쇄에서 가장 많은 7,067만 m³가 채취되었으며, 그 다음으로 산림골재 4,214만 m³, 바다골재 797만 m³, 선별세척 403만 m³, 육상골재 286만 m³, 기타골재 70만 m³, 하천골재 37만 m³ 순으로 선별파쇄와 산림골재의 채취량이 전국 채취량의 약 87.6%에 달한다. 시도별로는 경기도가 가장 골재를 많이 채취하였으며, 그 다음으로 경상남도, 충청남도, 인천광역시, 전라남도의 순이다. 2022년에는 231개 시군구의 약 64%인 147개 시군구에서 골재를 채취하였다. 100만 m³ 이상의 골재를 채취한 시군구는 44개이며, 이들 시군구에서는 전국 채취량의 72%인 약 9,269만 m³ 를 채취하였다. 2022년도에는 약 960개소 정도의 채취장이 운영되었으나 실제 골재를 채취한 채취장은 약 800개소이다. 이중 허가채취장은 350개소, 신고채취장은 450개소이다. 선별파쇄가 약 407개소로 가장 많으며, 산림골재는 187개소, 육상골재는 123개소 내외이다. 100만m³ 이상의 골재를 채취한 채취장은 14개소이며, 1만m³ 미만의 소규모 채취장도 약 105개소이다. 약 350여개의 허가채취장에서 허가기간은 최장 34.8년에서 최소 0.1년이며, 허가기간이 10년 이상인 채취장은 103개소이다. 2022년 이후에도 채취 가능한 채취장은 258개이지만 5년 내로 320여개 이상의 채취장이 개발종료되어 28개의 채취장만이 5년 이상 채취가 가능하다.

• Computers and Concrete
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• 제2권3호
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• pp.239-248
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• 2005

The article presents the results of examination of the fractal dimension D of concrete specimen fracture surfaces obtained in fracture toughness tests. The concretes were made from three different types of coarse aggregate: gravel, dolomite and basalt aggregate. Ordinary concretes (C40) and high-performance concretes (HPC) were subjected to testing after 7, 14, 28 and 90 days of curing, respectively. In fracture toughness and compressive tests, different behaviours of concretes were found, depending on the type of aggregate and class of concrete (C40, HPC). A significant increase in the strength parameters tested occurred also after a period of 28 days (up to the $90^{th}$ day of curing) and was particularly large for concretes C40. Fractal examinations performed on fracture replicas showed that the fractal dimension D was diverse, depending on the coarse aggregate type and concrete class being, however, statistically constant after 7 and 14 days for respective concretes during curing. The fractal dimension D was the greater, the worse strength properties were possessed by the concrete. A cross-grain crack propagation occurred in that case, due to weak cohesion forces at the coarse aggregate/mortar interface. A similar effect was observed for C40 and HPC made from the same aggregate. A greater dimension D was exhibited by concretes C40, in which case the fracture was easier to form compared with high-performance concretes, where, as a result of high aggregate/mortar cohesion forces, the crack propagation was of inter-granular type, and the resulted fracture was flatter.

• Coupled systems mechanics
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• 제7권5호
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• pp.509-524
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• 2018

A hierarchical multi-scale modeling strategy devoted to the study of a Bitumen-Bound Gravel (BBG) is presented in this paper. More precisely, the paper investigates the temperature-dependent linear viscoelastic of the material when submitted to low deformations levels and moderate number of cycles. In such a hierarchical approach, 3D digital Representative Elementary Volumes are built and the outcomes at a scale (here, the sub-mesoscale) are used as input data at the next higher scale (here, the mesoscale). The viscoelastic behavior of the bituminous phases at each scale is taken into account by means of a generalized Maxwell model: the bulk part of the behavior is separated from the deviatoric one and bulk and shear moduli are expanded into Prony series. Furthermore, the viscoelastic phases are considered to be thermorheologically simple: time and temperature are not independent. This behavior is reproduced by the Williams-Landel-Ferry law. By means of the FE simulations of stress relaxation tests, the parameters of the various features of this temperature-dependent viscoelastic behavior are identified.

• 한국산업융합학회 논문집
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• 제2권1호
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• pp.45-52
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• 1999

It is difficult to keep the balance of supply and demand for natural aggregates in recent years, because natural resources have become to be almost exhausted. Crushed stone is already used for coarse aggregate instead of river gravel at present. Now, crushed sand or sea sand should be used for fine aggregate, because natural sand also has been exhausted with a few exceptions around Nakdong River. The sea sand has a lot of problems which are the corrosion of reinforcement bars, the investment of facility for cleansing salt and the cost increase due to the insufficiency of industrial water. Therefore, it is necessary to produce and to utilize the crushed sand very actively, but some material properties which are related to water absorption, strength and chemical durability, prevent from determining the generalized criteria because its rocks make much differences in its physical and chemical characteristics. In this paper, fundamental physical properties of crushed sand, which comes from Daegu Subway construction fields, have been investigated for the usability on basic material of concrete. The optimum replacement ratio and the strength estimation method of crushed sand replacing natural sand also have been presented here through the compressive strength test of ready-mixed concrete cylinders.

• 자원환경지질
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• 제57권2호
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• pp.161-175
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• 2024

골재는 일반적으로 암석이 강에서 운반되거나 인공적으로 파쇄되어 형성된 모래와 자갈 등을 말하며, 건설 산업의 핵심 자원이다. 경상북도는 전국에서 가장 넓은 행정구역으로, 산림골재, 육상골재, 하천골재, 선별파쇄골재 등 다양한 종류의 골재를 생산하고 있다. 2022년 기준으로 약 696 만m³의 골재를 채취하였으며, 이 중 허가에 의한 채취물량은 약 407 만m³, 신고물량은 약 288 만m³이다. 경상북도의 골재수요는 레미콘 공급량의 추정 방법에 따라 1,239 만m³로 나타난다. 골재의 공급 측면에서는 약 120 개의 채취장이 운영되고 있으며, 대부분의 시군에서는 골재의 수요와 공급이 적절하게 유지되고 있다. 다만, 일부 지역에서는 경상북도 인접지역에 반입과 반출이 발생하고 있다. 경상북도의 골재의 반입과 반출이 많은 지역은 경부선을 따라 경상북도 남부와 대구광역시, 포항시로 연결되는 지역이며 인구의 분포와 높은 관련성이 나타난다. 경상북도는 인구 감소와 농촌 지역의 고령화, 지역 간의 균형 발전 부족 등의 문제에 직면하고 있으며, 연구결과로 제시된 GIS를 이용하여 출발지-도착지 분석을 통해 파악된 골재의 수요와 공급 흐름에서도 이러한 양상이 확인된다. 경상북도의 골재산업구조와 공간구조를 분석한 결과 현재 경상북도는 다양한 골재원의 공급으로 수요를 충족하고 안정적인 골재 수급이 유지되고 있다. 하천골재와 육상골재는 장기적인 개발이 어렵기 때문에 단기간 공급전략으로 유지될 수 있으며, 선별파쇄를 통한 공급은 원석 공급에 의존하여 안정성 유지가 어려운 상황을 고려하여 원석관리의 필요성을 제안하였다. 경상북도에서는 골재자원의 안정적 공급을 위한 장기적인 대안으로 산림골재가 중요 자원으로 부각되어 대규모 골재 채석장 개발의 필요성을 제시하였다. 본 연구결과는 골재 자원의 지속 가능한 관리와 안정적 활용을 위한 전략 수립에 중요한 정보를 제공할 것으로 기대된다.