농어촌발전(農漁村發展)과 전망(展望)

고재군 한국농공학회 1990 韓國農工學會誌 : 전원과 자원 Vol.32 No.2

農村計劃을 위한 施設의 調査

高在君,金文基,奇宇奭 農科大學 農業開發硏究所 1980 農業開發硏究 報告書 Vol.1 No.1

혼합제가 콘크리트의 내산성과 물리적성질에 미치는 영향에 관한 실험적 연구(II)

고재군 한국농공학회 1971 한국농공학회논문집 Vol.13 No.3

서해조수에 의한 콘크리트의 부식 방지법에 관한 연구

고재군 한국농공학회 1972 한국농공학회논문집 Vol.14 No.2

이 연구는 해수 작용에 대한 콘크리트의 내구성 시험의 일환으로 각종 배합설계에 있어서는 보통 시멘트 만을 사용, 혼화제로서 후라이애쉬, 포조리스, 빈솔레진등을 각각 보통시멘트에 사용, 포조란 시멘트만을 사용한 것등으로 구분하고 각 콘크리트의 공시체는 K. S규정에 준하여 만들어서 양생하였다. 그리고 압축강도 시험은 재령 7일, 28일 및 3개월 강도를 측정하고, 흡수율시험은 재령 28일 공시체로서 저불법(煮沸法)에 의하여 5시간 끓은 물에 당구어 흡수율을 측정 하였다. 이와같이 콘크리트의 물리적성질에 대한 시험 결과를 요약하면 다음과 같다. 1. 후라이애쉬를 혼화제로 사용한 콘크리트는 각 재령에 있어서 그 효과가 인정 되었으나 흡수율에 있어서는 보통 콘크리트와 같은 결과를 얻었으므로 그 효과는 인정할 수 없는 셈이다. 2. 포조리스를 혼화제로 사용한 콘크리트는 각 재령에 있어서 압축강도나 흡수율에 있어서 그 효과가 인정되며 후라이애쉬(강도)나 빈솔레진을 사용한 콘크리트 보다 더욱 큰 효과를 나타내었다. 3. 빈솔레진을 혼화제로 사용한 콘크리트는 각 재령에 있어서 압축강도나 흡수율에 있어서 그 효과가 인정되었다. 그러나 포조리스나 포조란시멘트를 사용한 콘크리트보다 약간 그 효과는 떨어졌다. 4. 포조란시멘트만을 사용한 콘크리트는 각 재령에 있어서 압축강도나 흡수율은 이 시험에서 가장 큰 효과를 나타내었으며 특히 장기 강도는 급증 현상을 보였다. 이 시험에서 포조란시멘트는 콘크리트의 품질개선에 있어서 바람직한 시멘트라고 생각된다. 5. 콘크리트의 압축강도와 흡수율간에는 희정기선관계가 성립 되었으나 이는 각 재령에 따라 일직하지 않고 조기재령에 비하여 장기 재령 일수록 더욱 급격한 강도의 변화율을 나타 내었다. 6. 후라이애쉬를 제외하고 포조리스나 빈솔레진을 혼화제로 사용한 콘크리트와 포조란 시멘트만을 사용한 콘크리트는 물리적 성질의 개선으로 미루어 볼 때 해수작용에 대한 내구성에 있어서도 그 효과가 기대될 것으로 본다. This study was attempted in order to search for phyosical properties on various mix designs of concrete as ne of studies relating top revention against corrosion by action of sea water in the West Sea. In this study, as concerete mix design, fly ash, pozzolith and vinsolresin were used as admixtures for normal portland cement respectively, and pozzolan cement and normal cement were also used for each plain concrete. Concrete specimens were made and cured in accordance with the Korean Standard Specifications for concrete. In thetest, compressive strengths of the specimens were measured at the following ages; 7-day, 28-days and 3-months. Absorption test was made by immersing the specimens in water kept at boiling temperature for 5 hours. The results obtained from the tests are summarized as follows; 1. The use of fly ash as an admixture in mix design of concrete, has an effect on compressive strength at each age. But it is actually not effective on absorption by concrete, as the result of the fly ash concrete is almost the same at that of ordinary plain concrete. 2. The use of pozzolith as an admixture in mix design of concrete, has an effect on both of compressive strength at each age and absorption rate. The pozzolith is more effective than vinsol resin, relating to improvement for physical proreties of concrete. 3. The use of vinsol resin as an admixture in mix design of concrete, has also an effect on both of compressive strength at each age and absorption rate. As the above fact, effectiveness of the vinsol resin is some what lower than pozzolith, as far as physical properties of the concrete are concerned. 4. Plain concrete used pozzolan cement only is the most effective on both of strength at each age and absorption rate in this study. The pozzolan cement is characteristic of higher strenth as the age is later. 5. Relationship between compreessive strengths and absorption rates of the concrete is shown by a different regression line dependingon ages. The gradient of the regression line is steeper as the age is later. 6. Throught physical test, it may be expected that the use of pozzolith and vinsol resinas asan admixture respectively will be better resistant than fly ash or ordinary plain concrete and that plain pozzolan concrete will also be the best resistant to action of sea water due to improvement of theirphysical properties.

혼화제가 콘크리트의 물리적 성질과 내산성에 미치는 영향에 관한 연구

고재군 한국농공학회 1971 한국농공학회논문집 Vol.13 No.2

농업토목(農業土木) 기술발전(技術發展)에 대(對)한 제언(提言)

고재군 한국농공학회 1983 韓國農工學會誌 : 전원과 자원 Vol.25 No.2

모르타르의 내구성에 관한 연구

고재군 한국농공학회 1969 韓國農工學會誌 : 전원과 자원 Vol.11 No.4

이 실험(實驗)은 시멘트모르타트를 0.1N-NaOH의 알카리용액(溶液)에 침지(浸漬)시켜 alkali작용(作用)에 의한 모르타르의 부식(腐蝕)이 모르타르의 물리적(物理的) 성질(性質)에 미치는 영향을 구명(究明)하여 내고기성 모르타르 또는 콘크리트의 배합설계(配合設計)에 기초자료를 제시(提示)하고저 기도(企圖)하였던 바 이를 요약(要約)하면 다음과 같다. 가. 공시체(供試體)는 5cm입방체(立方體)의 모르타르로서 그 배합비(配合比)(중량(重量))는 1:1, 1:3, 1:5, 1:7, 1:10의 5종(種)을 만들어 사용(使用)하였다. 나. 공시체(供試體)의 물리시험(物理試驗)은 재령(材令) 7일(日), 28일(日), 3개월(個月) 6개월(個月)의 압축강도시험(壓縮强度試驗)과 5시간(時間) 자비(煮沸)의 흡수율시험(吸水率試驗)을 하였다. 다. 알카리시험(試驗)에서는 0.1N-NaOh 용액(溶液)을 사용(使用)하고 7일간격(日間隔)으로 감량(減量)을 7주간(週間) 계속(繼續) 측정(測定)하였다. 라. 알카리작용(作用)에 의(依)한 모르타르의 부식(腐蝕)은 배합비(配合比) 1:1, 1:3에서는 전연(全然) 생기지 않았고 1:5와 1:7에서 7주후(週后) 각각(各各) 3.5%와 6.26%로서 미량(微量)이였으나 1:10에서는 36.6%의 상당(相當)한 감량율(減量率)이였다. 그러나 같은 농도(濃度)의 고산용액에서는 같은 침액기간(浸液期間)(7주간(週間))을 통(通)해서 감량율(減量率)을 보면 배합비(配合比) 1:1에서 20.4% 1:3에서 25.1%, 1:5에서 56.8%, 1:7에서 72.2% 그리고 1:10에서 92.0%이므로 알카리의 작용(作用)에 의한 모르타르의 부식(腐蝕)은 산(酸)의 작용(作用)에 의한 부식(腐蝕)에 비(比)해서 극(極)히 적다는 것을 알 수 있다. 마. 보다 내고기성 모르타르를 만들기 위하여 배합비(配合比)를 1:7 또는 더 부배합(富配合)이고 흡수율(吸水率)은 5시간(時間) 자비(煮沸)하였을 때 20% 이하(以下) 밀도(密度)는 $1600kg/m^3$이상(以上) 그리고 사용수량(使用水量)은 시공연도(施工軟度)을 감안하여 수밀성(水密性)을 높이기 위하여 될 수록 소량(少量)으로서 더욱 장기양생(長期養生)이 요망(要望)되었다. 한편 내산성(耐酸性) 모르타르의 품질(品質)은 내고기성 모로타르가 되므로 콘크리트의 배합설계(配合設計)에서는 내산성(耐酸性)의 품질(品質)을 유지(維持) 또는 향상(向上)시킴으로써 알카리의 작용(作用)에 의(依)한 피해(被害)를 면(免)할 수 있다고 본다. The experiment was carried out as one of the basic studies to improve the alkali-resistance of cement mortars and it was conducted to investigate some propetties of mortars relating to weight losses when exposed to 0.1 N salution of sodium hydroxide. The experiment and the results obtained are summarized as follow; 1. The specimens used in this experiment were made of 5 centi-meter cubes of mortar having such various ratios of mix by weight as 1 : 1, 1 : 3, 1 : 5, 1 : 7 and 1 : 10. 2. Physical tests included compressive strengths at 7 days, 28 days, 3 months, and 6 month, and 5 hour boiling absorption test. 3. In alkali test, every specimen was immersed into 0.1 N solutions of sodium hydroxide. The specimens exposed to the alkali solution were weighed to determine the weight losses of the alkail-corroded at one week interval for 7 week's exposure and the old alkali solutions were also changed to fresh solutions when weighed the weight losses by alkali attack at one week interval. 4. According to the alkail test after 7 week's exposure, no weight losses were observed on ratios of mix 1:1 and 1:3 and slight weight losses occurred on ratios of mix 1:5 and 1:7, but relatively large amount of weight losses were showed by 36.6 per-cent on ratios of mix 1:10. It was also found that the weight losses of the alkali-corroded were extremely lower than those of the acid-corroded at the some concentrations as 0.1 N of solutions. 5. In order to make better quality of alkali-resistant mortar it might recomend that a 1:7 mix or richemixes, use of small amount of mixing water for watertight, 20 per cent or less absorption by 5 hour boiling 1,600 kirogram per cubic meters or denser densities by absolute dry base are available for physical properties of mortar. It could conclude acid-resistant mortars were so high alkali-resistant, that it is expected to make and improve the acid-resistant mortars for getting rid of damages by alkali attack.

관거의 응력해석

고재군 한국농공학회 1974 한국농공학회논문집 Vol.16 No.1

용수로(用水路)의 유형별(類型別) 경제성(經濟性) 검토(檢討)

고재군,이신호 한국농공학회 1983 韓國農工學會誌 : 전원과 자원 Vol.25 No.3

This paper compares total construction and maintenance costs for the life time of three different types of conventional irrigation canals. The conventional canal types consist of concrete bench flumes: concrete-lined canals, and earth canals. The total expenses were grouped into three categories: net construction costs, maintenance cost, and the interest and other expenses. The construction costs were used to compensate the costs for conveyance water losses from three types of canals, and were added to the total expenses. The total expenses were then converted to present values, which were used as a criterion to evaluate economical feasibility of the systems. For a fixed life time of an irrigation system being 60 years, the total expenses for concrete bench flume canals were found to be the most economical. The expense ratios of concrete-lined and earth canals to the costs for the bench flumes were 1. 2 and 3. 1 at the conveyance discharge rate of 1㎥/sec; 1.4 and 2.5 at the rate of 2㎥/sec, respectively. In this case, the average annual interest rate was assumed to be fixed at 5.5%. And the ratios were significantly increased with a lower annual interest rate. Initial construction costs for earth canals were lower than those for concrete bench flumes. However, total expenses for earth canals increased rapidly and become greater than the bench flumes after a few years. For annual interest rate of 5.5%, the bench flumes becomes more economical after 3 years to convey the irrigation water of 1㎥/sec; after 5 years to do the same of 2㎥/sec. The results from this study demonstrate that the bench flumes are economically feasible in a long run. Cheaper conveyance systems like concrete-lined and earth canals demand higher maintenance costs, which often escalate total expenses to exceed those for the bench flumes within a few years following the construction.

Cemesol混和劑가 콘크리트의 壓縮强度와 耐酸性에 미치는 影響에 關한 硏究

高在君 서울대학교 1975 서울대학교 論文集 Vol.25 No.-

This study was conducted to investigate some effects of cemesol on acid­resistance and compressive strength of concrete. In mix design of concrete, the cemesol was used as an admixture of cement, and it was added to the mix in an amount equal to 0.1%, 0.2%, 0.3%, and 0.4% by weight of cement of mix. Concrete specimens were made in accordance with the Korean Standard Specification for concrete and they were tested for acid­resistance and compressive strength at 2 weeks intervals through 8 weeks. The tests were performed in two cases such as non­curing and curing for 28 days. The results obtained from the tests are summarized as follows. 1. Refering to acid­resistance test, the cemesol was comparatively effective at every cemesol content except 0.3% in case of non­curing and it was found that cemesol content of 0.4% is most optimum. On the other hand, the cemesol was ineffective in case of curing, but it was seen that cemesol content of 0.1% is some effective at 6 weeks to 8 weeks only. 2. Refering to compressive strength test, the cemesol was remarkably effective at a content of 0.1%, but it was also shown most ineffective at content of 0.3% in case of non­curing. On the other hand, the cemesol was comparatively effective at every content of cemesol except a content of 0.2% in case of curing and it was determined that the cemesol content of 0.3% is an optimum content. 3. As results from the tests, since optimun cemesol content varied depending upon acid­resistance, compressive strength and cases such as non­curing and curing, it is desirable to choose an optimum cemesol content suitable for purposes and circumstances of construction works or conditions of location. 4. Relationship between corrosive rate and compressive strength was proportional in case of non­curing, but inversely proportional in case of curing. It was found that corrosive rate for 8 weeks does not influence compressive strength in case of non­curing but compressive strength in case of curing begins to vary under the influence of corrosion is more serious to compressive strength in case of curing than that in case of non­curing.