• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.232-233
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• 2018

Among the recent environmental pollution, indoor air pollution has an adverse effect on the health of indoor residents. Radon, one of the causes of indoor air pollution, is released from concrete, gypsum board and asbestos slate among building materials. Radon is a primary carcinogen and is a colorless, tasteless, odorless inert gas that adheres to airborne dust and enters the body through breathing. At this time, there is a risk of developing cancer if the alpha rays from the lononggas entering the human body destroys the lung tissue and is continuously exposed to a high concentration of lonon gas. The World Health Organization (WHO) has emphasized the reduction of radon and its exposure to radon by classifying it as a first-level carcinogen, but many people have not recognized it yet, and the research is underdeveloped. Therefore, this study was carried out to investigate the properties of adsorbed coconut radon to prevent the inflow of radon gas, which is an air pollution source of indoor air, and to prevent inflow into the human body.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.235-242
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• 2005

This study is on the evaluation of performance of polymer cement mortar which is used for pre-wetting spray method. Pre-wetting spray method is an epoch-making method to repair concrete structures damaged, which is added a small quantity water preciously to dry mortar to reduce dust and rebound and spray mortar mixed with fixed quantity water at nozzle before spray. The result showed that physical performance such like compressive, flexural and adhesive strength of polymer cement mortar, TS 100 used for pre-wetting spray method was superior to other repair mortar. Also durable performance such as resistance on permeability of chloride ion, carbonation, chemical and freezing-thawing was excellent.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.55-62
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• 2010

This is an experimental research in order to judge the applicability of sewage sludge incineration ash having applied the mixing proportion needed to manufacture bricks and to do plaster work with addition of hwangtoh and slaked lime as a part of the methods for utilizing the wastes produced from sewage sludge incineration ash. Based on the results from experiment and analysis, it is judged that, in case of mixing proportion of 1:2 for the purpose of plastering and masonry work, the cement mortar produced by using a 10% addition ratio of sewage sludge incineration ash with mixture of hwangtoh covering all range of addition ratio, and also the cement mortar produced by using a 20% of sewage sludge incineration ash together with 0% and 10% addition ratio of hwangtoh, was possible to be applied to the practical use. In case of mixing proportion of 1:7 for manufacture of bricks and blocks, if such brick and block products are produced with 10% and 20% addition ratio of sewage sludge incineration ash having added aggregate fines or stone dust that has been actually used in brick and block manufacturing, it is judged that these bricks and blocks could be practically used in the job sites, although strength development is a little bit lower.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.628-631
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• 2004

In this paper, mechanical properties of concrete incorporating CKD are discussed with W/B and fluidity. For setting properties, an increase in W/B retarded setting time greatly in $5^{\circ}C$, while accelerated in $20^{\circ}C$. For fluidity, an increase in slump delayed the setting time with dosage of SP agent. The presence of CKD has little influence on setting time compared with plain concrete. For compressive strength, an increase in maturity enhanced compressive strength. Fluidity had no relation to compressive strength. At low curing temperature, concrete with CKD has slight strength loss compared with plain concrete. However, remarkable strength loss at low curing temperature in early stage was not found, which can be applicable to low temperature environment concrete placing.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.521-524
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• 2006

In this paper, admixture factors affecting the properties of lightweight foamed concrete incorporating cement kiln dust(CKD) and fly ash(FA), respectively are discussed. Increase in CKD contents resulted in loss of fluidity and decrease in settlement of concrete noticeably. Moreover, the higher the unit weight is, the smaller the settlement depth is. The use of CKD resulted in slight decrease in compressive strength and tensile strength compared to that with other admixture. However, all mixtures met the requirement of strength prescribed in Korean Industrial Standards.

• Proceedings of the Korean Institute of Building Construction Conference
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• v.y2004m10
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• pp.51-54
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• 2004

This paper investigated the results of mixture proportion and compressive strength of concrete incorporating mineral admixtures. W/B and contents of mineral admixtures were selected as test parameters. According to test results, use of mineral admixtures resulted in a reduction of fluidity and air contents caused by increased fine particles and absorption effect of FA on reduction of AE agent. Thus, increase of SP and AE agent was needed to maintain the same fluidity and air content as plain concrete. At early stage, use of CKD was beneficial to the compressive strength while at 28days. incorporation of FA and BS had favorable effect on the compressive strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.253-256
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• 2005

This paper is to investigate the mixture proportion, compressive strength and drying. shrinkage of concrete depending on mineral admixtures such as fly ash (FA), blast furnace slag (BS) and cement kiln dust (CKD) under various contents of admixtures. The use of CKD had little effect on strength development at 3 days, while the use of FA and BS lead to similar compressive strength compared with that of control concrete. Concrete with CKD exhibited a reduction of compressive strength at 91 days, meanwhile concrete with FA and BS had a increase compared with that of control concrete. Drying shrinkage of concrete depending on CKD and BS increase compared with that of control concrete about $10\∼20\%$, while the use of FA exhibited reduce compared with that of control concrete about $10\∼15\%$.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.483-489
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• 2020

Particulate matter is divided into PM10 (particle diameter of 10 ㎛ or less) and PM2.5 (particle diameter of 2.5 ㎛ or less), which are approximately 1/5 of the thickness of the hair. Due to its effect on the human body, lung disease, arteriosclerosis and heart It is known as a carcinogen that causes various diseases such as diseases. It is known that the main cause of such fine dust is nitrogen dioxide (NOx), which is emitted from automobiles in about 57.3% of urban roadsides. Therefore, in this study, as part of the development of functional construction materials to reduce NOx generated from road transport pollutants, comparative evaluation of NOx reduction performance was conducted according to the replacement rate of cement mortar in which cement was replaced with a porous material. In addition, the NOx reduction performance of cement mortar according to the photocatalyst application method and the number of applications was compared an d evaluated. As a result of the experiment, when activated ocher was substituted by 30%, it showed a reduction effect of about 32.7%, showing the best reduction performance.

• Tuberculosis and Respiratory Diseases
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• v.41 no.6
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• pp.651-657
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• 1994

Asbestos is widely used in the textile, asbestos cement, construction products, friction material, paper products, insulation products, chemical and plastic products because of its heat resistance, flexibility, tensile strength, and texturability. It is now generally recognized that longterm and excessive inhalation of asbestos dust causes asbestosis, lung cancer, malignant mesothelioma and malignancies in other organs such as cancer of gastrointestinal tract, leukemia, lymphoma. Although eighty thousand tons of asbestos has been annually consumed since 1979 in korea, it has not been reported asbestos and lung cancer by asbestos dust so far, while a case of mesothelioma was officially diagnosis as a occupational disease at 1993. We experienced firstly a case of asbestosis and lung cancer caused simultanously by occupational asbestos exposure 11 years, which was confirmed by chest x-ray, pulmonary function test, chest CT and HRCT, bronchoalveolar lavage, and gallium scan. And so We present a case of asbestosis, pleural effusion and lung cancer with a review literature.

• Journal of the Korea Institute of Building Construction
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• v.24 no.3
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• pp.309-318
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• 2024

This research investigated the feasibility of incorporating industrial by-products into precast concrete formulated with blast furnace slag and natural gypsum. Specifically, the study examined the effects of incorporating steelmaking slag(STS slag), combined heat power plant fly ash, and return dust. The optimal amount of these by-products was determined by measuring air content, slump, and compressive strength at various incorporation levels. Results demonstrated that compressive strength was enhanced across all levels of by-product addition. Notably, incorporating 10% of the by-products led to exceptional early-age strength development. However, a 20% addition of combined heat power plant ash significantly reduced the slump value by approximately 40%. Considering these findings and the requirement for rapid strength development in precast concrete applications, a 10% incorporation of industrial by-products was deemed optimal due to its ability to accelerate early-age strength gain.