• Journal of the Korea Institute of Building Construction
• /
• v.14 no.3
• /
• pp.230-236
• /
• 2014

This study was carried out to investigate the manufacturability of artificial lightweight aggregate as a way to recycle basalt powder sludge, which is a waste produced during the manufacturing process of basalt in Jeju. Powdered waste glasses and calcium carbonate are used to improve the characteristics of manufactured artificial lightweight aggregate. Especially, considering the complex factors of basalt powder sludge, powdered waste glasses, and sintering method, the amount of calcium carbonate is appropriate at the 9 wt.% in order to improve the intumescent of lightweight aggregate. Also, the amount of powdered waste glasses is effective with using less than 50 wt.% and applying the direct sintering method at the same time on decreasing the absorption of lightweight aggregate. Furthermore, in order to manufacture artificial lightweight aggregate of high quality with a low specific gravity and low water absorption, it is considered to be more effective to apply the direct sintering method after the surface of artificial lightweight aggregate is covered with powdered waste glasses.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.1B
• /
• pp.7-16
• /
• 2005

Resource Reservation Protocol(RSVP) can provide Quality-of-Service(QoS) guarantees for real-time services in wired networks. However, RSVP suffers from mobility problem in the mobile Internet. Therefore, to provide seamless QoS services, it is needed that a mobile node makes a reservation everywhere it visits. Recently, many protocols have been proposed to provide QoS guarantees through advance resource reservation. But, these proposals have problems with a waste of bandwidth and the signaling overhead due to advance resource reservation. In this paper, we propose new advance resevation protocol, Proportional Aggregate RSVP(PA-RSVP) to minimize the resource reservation bandwidth and the signaling overhead in the mobile Intemet while providing QoS guarantees. Based on the performance evaluation, we show that the proposed protocol provides an improved performance over existing protocols under various system conditions.

• Economic and Environmental Geology
• /
• v.57 no.2
• /
• pp.161-175
• /
• 2024

Aggregate typically refers to sand and gravel formed by the transportation of rocks in rivers or artificially crushed, constituting a core resource in the construction industry. Gyeongsangbuk-do, the largest administrative area in South Korea, produces various sources of gravel, including forest, land (excluding other sources), river, and crushed stone. As of 2022, it has extracted approximately 6.96 million cubic meters of aggregate, with permitted production totaling around 4.07 million cubic meters and reported production of about 2.88 million cubic meters. The aggregate demand in Gyeongsangbuk-do is estimated to be 12.39 million cubic meters according to the estimation method in Ready-Mix Concrete. From the supply perspective, about 120 extraction sites are operational, with most municipalities maintaining an appropriate balance between aggregate demand and supply. However, in some areas, there is inbound and outbound transportation of aggregate to neighboring regions. Regions with significant inbound and outbound aggregate transportation in Gyeongsangbuk-do are areas connected to Daegu Metropolitan City and Pohang City along the Gyeongbu rail line, showing a high correlation with population distribution. Gyeongsangbuk-do faces challenges such as population decline, aging rural areas, and insufficient balanced regional development. Analysis using GIS reveals these trends in gravel demand and supply. Currently in this study, Gyeongsangbuk-do meets its demand for aggregate through the supply of various aggregate sources, maintaining stable aggregate procurement. River and terrestrial aggregates may be sustained as short-term supply strategies due to the difficulty of longterm development. Considering the reliance on raw material supply for selective crushing, it suggests the need for raw material management to maintain stability. Gyeongsangbuk-do highlights quarries in the forest as an important resource for sustainable aggregate supply, advocating for the development of large-scale aggregate quarries as a long-term alternative. These research findings are expected to provide valuable insights for formulating strategies for sustainable management and stable utilization of aggregate resources.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.11a
• /
• pp.15-18
• /
• 2003

Development of the construction industry generally exhausts natural aggregate. Hence it is problem to the lack of supply and quality deterioration, so the resource saving and protection of environment is made an effort through recycling by-product. This study presents that fundamental properties of concrete which used cooper slag as alternate sand of low fineness modulus and plan of cooper slag as concrete aggregate. Testing factors are concrete's slump, air contents, unit weight and compressive strength. The results of this study are as follows; (1) Concrete slump is generally satisfied with the condition but is inferior to the others in substitution rates 30%. Also air contents are 3.1-4.1% and go up according to increase substitution rate. (2) Unit weight increase in 1.1% as the mixing ratio of cooper slag argument 10%. (3) compressive strength of cooper slag concrete is similar to plain and especially higher 11-15% in W/C 45%, 50%. So it seems that aggregate mixed cooper slag is suitable to low water-cement ratio mixture.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.565-570
• /
• 2001

Annually, Taiwan generates approximately 2 million tons of inorganic wastes in the form of sludge, fly ash and slug. To increase the added value of waste and maintain the increasingly insufficient supply of natural gravel, large public construction projects account for this large demand each year. future architectural trends are leading towards high-rise buildings. In light of the above, Center for Environmental, Safety and Health Technology Development, Industrial Technology Research Institute has developed the technology of manufacturing cold-bonding, sintering and bloating types of lightweight aggregates with a specific gravity ranging between 0.7~1.7, water absorption rate < 30%. The lightweight aggregate verified by physical property tests can be used as a substitute for the natural aggregate, which generally appears in replacing gravel in concrete, soundproofing and heat insulation materials. Doing so would not only moderate waste disposal problems, but also achieve the goal of resource recovery.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2006.05a
• /
• pp.93-96
• /
• 2006

As the importance of recycled materials is being emphasized more in the Korean construction market, the production quality has been improved to a significantly high level. Compared to the high quality, however, there are used very limitedly. Among recycled construction materials, recycled aggregates produced through the retreatment of waste concrete are drawing attention because of lack of natural aggregate and heightened consciousness of resource saving and environmental protection and, as a consequence, they are close to natural aggregates in terms of production technology and quality. Despite the high quality and productivity, however, the utilization of recycled aggregates is very low.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.252-257
• /
• 1999

The distinguished geological characteristic of Taegu area is consist of anisotropic shale or sedimentary rock. Therefore if rocks are used for construction, it would've some difficulties of reuse showing the aspect of resource engineering. We made physical and mechanic properties for rock discrimination and then whether it had utilization worth or not. So we studied the engineering propriety through the aggregate tests based on rock's in laboratory. The last passed aggregate were D, E and B1 at KS and the rest couldn't use the place where weather phenomenon is caprice. This sis for base-line data of aggregate development research before the porpriety investigation for aggreagte of excavated rock in Taegu area.

• Journal of Korea Trade
• /
• v.23 no.8
• /
• pp.27-44
• /
• 2019

Purpose - The purpose of this paper is to develop a tractable general-equilibrium model of examining the impact of human resource management on intra-industry trade. Commonly, managers of Korean firms are promoted internally. It necessitates a study of human resource management and its impact on an industrial equilibrium. Design/methodology - This paper relies on theoretical analysis. We build a model in firms are hierarchical; an entrepreneur, managers, and workers. All individuals have heterogeneous managerial talents, which are the main source of managerial quality. Firms search talents for prospect managers, and eventually delegate them to supervise workers. The searching incurs a sunk cost. Findings - Our finding is as follows. Country 1, relatively abundant of managerial talents, can gain more from trade than Country 2, relatively scarce of managerial talents. This is because the higher searching cost leads to the lower survival rate of firms in Country 2. Implicatively, good jobs are destroyed, and aggregate income falls in Country 2. Originality/value - According to our study, relative abundance of managerial talents affects distribution of firm size and determines trade gain. This study can contribute to the literature of organization management and trade.

• KIEAE Journal
• /
• v.14 no.1
• /
• pp.131-138
• /
• 2014

The recent interests in securing alternative resource have increased due to environmental issues and exhaustion of natural resources. The government notices production of recycled aggregate using waste concrete as the substitute of the natural aggregate. However, It's important to reduce environmental burden being inevitably made in the process producing recycled aggregate. In this study, the scenarios of transportation distance were set in the transportation phase of production of recycled aggregate. In addition, The possibility of emissions and reduction of carbon dioxide were studied depending on the scenarios. For this study, data about a amount of waste concrete, transportation distance, kind of vehicle, the number of required vehicle, fuel efficiency of vehicle and etc were gathered from 15 companies of intermediate treatment and 60 constructions sites located in Daegu city and Kyungpook area. Based on those data, fuel consumptions and $CO_2$ emissions according to the transportation scheme of waste concrete were calculated. As a result of the study, the emission of carbon dioxide was possible to be reduced by 27.8~75.4% depending on the scenarios of transportation distance.

• Resources Recycling
• /
• v.16 no.5
• /
• pp.25-30
• /
• 2007

In Korea, reutilization of construction waste is gaining attention as construction waste generated increases continuously. Currently, the concrete waste is simply crushed and used as a low value application such as paving, back filling, etc. To meet the demand of aggregate for construction and the resource efficiently, production of high quality recycled aggregate is necessary. Therefore, in this study, a better process for production of high quality recycled aggregate was developed using combination of heat pretreatment and autogenous milling. Test results showed that the recycled aggregate has a density of $2.5\;g/cm^3$ and a water absorption ratio of 3.0%, which meet the specification of the first class of KS F 2573. Currently, a pilot scale autogenous mill is being constructed and tests will be further conducted to develop a commerce-scale process.