• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.3
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• pp.146-151
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• 2013

In this study, the effect of addition of waste glassy slag produced from recycling of spent catalyst (denoted as waste glass hereafter) on the physical properties of artificial aggregates made of coal bottom ash and dredged soil (7 : 3 by weight base) was evaluated. Especially, the bloating behavior of artificial aggregates was analyzed by performing the relation study between the apparent density, water absorption and microstructure. The apparent density of artificial aggregates increased slightly with sintering temperature at $1050{\sim}1150^{\circ}C$, but decreased above $1150^{\circ}C$ showing bloating phenomenon. The bloating behavior of artificial aggregates was decreased so the apparent density increased with amount of waste glass added. Also, the water absorption of artificial aggregates decreased with sintering temperature. Above $1200^{\circ}C$, big fissure and much liquid were formed at the surface of artificial aggregates and these phenomena could be suppressed by increasing amount of waste glass added. The artificial aggregates fabricated in this study had an apparent density of 1.1~1.6 and water absorption of 8~22 % which meet KS requirements for the artificial lightweight aggregates.

• Journal of the Korea Institute of Building Construction
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• v.10 no.1
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• pp.147-153
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• 2010

The recycling of demolished concrete as an alternative source of coarse aggregates for the production of new concrete can help to solve the growing waste disposal crisis and the problem of the depletion of natural aggregates. The purpose of this study is to investigate the chloride migration of recycled aggregate concrete containing pozzolanic materials by the chloride migration coefficient. The specimens were made with recycled coarse aggregate at various replacement ratios (10, 30, 50%) and metakaolin, blast furnace slag, and fly ash is replaced for recycled concrete with a mixing ratio of 20%. The major results are as follows. 1) The compressive strength of recycled aggregate concrete containing pozzolanic materials increases as the curing age and chloride diffusivity decreases. 2) When the replacement ratio of recycled coarse aggregate is 30%, the chloride migration coefficient of recycled concrete containing blast furnace slag or metakaolin that shows a value similar to or lower than that of plain concrete at all ages.

• Resources Recycling
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• v.13 no.4
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• pp.3-10
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• 2004

The intension of this study is to produce ordinary portland cement using ash, both bottom ash and fly ash, obtained from municipal solid waste incineration ash (MSWI). We used limestone, waste molding sand, shale, slag from converting furnaces and fly ash as main raw materials and mixed them, setting the lime saturation factor (LSF) within 91.0, the silica modulus (SM) within 2.40, and iron modulus (IM) within 1.80. We conducted tests adding bottom ash alone 1, 2 and 3％ by weight, respectively, and a mixture of bottom ash 0.9％ and fly ash 0.1 ％ by weight. The result of analysis on clinker shows that the more ash is added, the lower the burnability index (B.I.) falls, lowering the mineral evolution of calcium silicate accordingly. From the measurement of compressive strength we have learned that the more ash is used, the lower the strength becomes.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.646-652
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• 2014

Data of pollution incidents which occurred in shipyards of South Korea for 10 years from 2004 to 2013 were collected and analyzed in order to propose the plans for the prevention of pollution incidents in shipyards. Total number of pollution incidents in shipyards was 103 cases over the nation of Korea for the recent 10 years and the average annual number was about 10 cases, and annual cases tended to increase from 8 cases in 2004 to 23 cases in 2010 and then to decrease to 9 cases in 2013. The location data of pollution incidents showed 32 cases in Busan metropolitan city (31%), 30 cases in Jeonnam (29%), 21 cases in Gyeongam (21%), 5 cases in Jeju (5%), 4 cases in Gangwon (4%), 4 cases in Gyeongbuk (4%), 3 cases in Chungnam (3%) and 3 cases in Incheon metropolitan city (3%). According to the data of work types of shipyards, 60 cases happened during the work of ship repair (58%), 25 cases during the work of ship breakup (24%), 10 cases in the course of ship building (10%) and 8 cases by others (8%). The data of pollutant type showed oil and oily mixtures to be 59 cases (57%), waste paint dust to be 22 cases (21%), iron dust and welding slag to be 13 cases (13%), wastes to be 4 cases (4%), waste FRP powder to be 3 cases (3%), and others to be 2 cases (2%). The plans for the prevention of pollution incidents in shipyards of Korea were proposed as follows; (1) Observance of the related laws and regulations, (2) Establishment and implementation of action plans to prevent areas dense with shipyards from causing pollution incidents, (3) Establishment and implementation of oil pollution prevention plans in shipyards, especially during the ship repair and breakup works, (4) Preparation of measures to solve civil complaints against pollution incidents in shipyards, and (5) Improvement in national management for the control of shipyards.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.619-626
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• 2008

There have been numerous studies to develop eco-friendly concrete. The attempt to reduce the amount of cement usage is suggested as one of the solutions for eco-friendly concrete. To reduce the amount of cement usage, the pozzolan-reaction materials such as ground granulated blast furnace slag, fly ash, and meta kaolin are widely used as the mineral admixture. Hwangtoh which deposited broadly in Korea is a well known eco-friendly material and the activated Hwangtoh with pozzolan-reaction can be practically used as a mineral admixture of concrete. Meanwhile, PET fiber made of recycled PET bottle is a type of recycled material, which can be used to control micro cracks in concrete. But the study about concrete mixed with recycled PET fiber is insufficient and the research of Hwangtoh concrete mixed with PET fiber is urgently needed presently. In this study, experiment and analysis flexural behavior of Hwangtoh concrete blended with recycled PET fiber are carried out. The results are discussed in detail.

• Journal of the Korean Ceramic Society
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• v.39 no.7
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• pp.680-686
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• 2002

The solidification/stabilization mechanism of each cementious material was investigated. It was found that when $C_3$S was hydrated , the Pb element could be transferred to the insoluble Ca[Pb(OH)$_3$.$H_2O$]$_2$and the Cr element to the CaCr $O_4$$H_2O$. The addition of heavy metal tends to delay the hydration until initial 7 days. The Pb element as also delayed the hydration and the Cr element was substituted for the ettringite. On the occasion of the hydration of $C_4$ $A_3$ $S^{S}$, the Pb and Cr ions were solidified/stabilized by the substitution into the ettringite and/or monosulfate. Leaching of the Pb, Cr and Zn elements in the solidified material was extremely little, indicating that heavy metals were effectively solidified/stabilized in the hydrated cementious materials. Solidification/stabilization of heavy metal ions in the industrial wastes such as the STS, BF and COREX sludge was investigated. In case of the mixing ratio of cement and slag was 3 : 7, leaching of hazardous heavy metal ions was very little, indications that the solidification and stabilization was very successful.l.

• Clean Technology
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• v.19 no.4
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• pp.423-429
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• 2013

This study aimed to develop flowable backfill material using oyster shell, coal ash, and surplus soil. The high temperature (> $800^{\circ}C$) reaction was required to convert $CaCO_3$ to CaO. The solid specimens formed by pozzlanic reaction between CaO and coal ash showed low unconfined compressive strength. The effect of kaolin and blast furnace slag was also examined. It was found that CaO and coal ash could not be utilized due to high cost and low performance. The use of oyster shell without calcination ($CaCO_3$) was evaluated. The specimens composing of oyster shell and cement showed the higher unconfined compressive strength than that composing of coal ash and cement. However, use of oyster shell is limited in mortar due to the presence of salt. Addition of soil into oyster shell-coal ash-cement mixture satisfied the specification of flowable backfill material by optimizing their ratio.