건설폐기물의 현장 재활용을 위한 공정개선 효과

최형일 ( Hyung Il Choi ),정경훈 ( Kyung Hoon Cheong ),채희정 ( Hee Jeoung Chae ),김연풍 ( Youn Poong Kim ),조도호 ( Do Ho Jo ),설동화 ( Dong Hwa Seol ),김정애 ( Jeung Ae Kim ) 조선대학교 공학기술연구원 2008 공학기술논문지 Vol.1 No.1

The conclusions of this study are summarized below: First, as a result of the evaluation of the mobility of the sorting and separating devices that are moved to and operated at the sites where construction waste is generated, very satisfactory results, namely about 2 days (13. 15 hr) to finish sorting and separating construction waste, were drawn. Second, 142.1 tons per hour were sorted and separated (treatment ability) on average. In terms of volume, about 32.6% of the treatment ability was higher than the suggested 80 ㎥/hr, at 106.1 ㎥/hr. Third, as a result of a grain test conducted on the 10~25 mm of recycled aggregates produced after injecting a good quality of sorted and separated waste concrete into the existing crushing and pulverizing process it was found that about 76.3% of the recycled aggregates remained in the 10 mm grains. For the absorption rate, 6.42% in the grains of less than 10 mm. 3.93% in the 10~25 mm grains, and 6.12% in the 25~40 mm grains were demonstrated. The moisture content was about 8.8% in the less than 10 mm grains, 4.74% in the 10~25 mm grains, and 6.11 % in the 25~40 mm grains. Fourth, in the case of operating sorting and separating devices for the on-site recycling of construction wastes, the noise level was found to be about 44.5~76.0 dB (A) around the target facilities and about 54.8~79.4 dB (A) within the working radius after measuring the levels of noise, vibration and dispersed dust, in view of the effort to minimize disputes and civil petitions deriving from noise, vibration and dispersed dust. The concentration of dispersed dust generated - when simultaneously operating the sorting process of the forward treatment for construction wastes and the production process for recycled aggregates - was about 0.089~0.707 mg/㎥ in the area around the facilities and was about 0.158~0.335 mg/㎥ at the site boundary. These levels actually met the permitted dust exposure level of 2~10 mg/㎥ of the first type to the third type of dispersed dust in relation to the working environment.

도로교통소음의 수평·수직적 전달 및 감쇠 특성

최형일,채희정,김연풍,조도호,설동화,정숙경,김정애 조선대학교 생산기술연구소 2007 生産技術硏究 Vol.29 No.1

This study has been conducted to achieve the following objectives: First, in order to understand the horizontal propagation and attenuation characteristics for the road traffic noise, we selected actively developed areas within 100 meters away from the road to measure the level of traffic noise near a road. To measure the noise near a railroad, we selected areas within 100 meters away from the road. In this way, we analyzed the horizontal propagation and attenuation characteristics for the traffic noise occurring in diversified areas. Second, in order to understand the vertical propagation and attenuation characteristics for the road traffic noise, we measured and analyzed the distributional characteristics of vertical sound pressure levels on each floor of multi-storied apartment buildings according to changes of traffic load and types, and the existence or nonexistence of soundproof walls. For the case of the road traffic noise, we also selected we measured and analyzed the different noise levels on each floor of multi-storied apartment buildings from the soundproof wall. The results of Horizontal propagation and attenuation characteristics for the road traffic noise are as follows: In cases of the soundproof wall + raising ground, raising ground, cutting land, and flat land as distance increases, the sound pressure level steadily decreases. The soundproof wall + raising ground has an especially high distance decrease compared to the other areas, and the sound pressure level for the raising ground is higher than that of the cutting land with a measurement of 10.7~12.1dB(A). Vertical propagation and attenuation characteristics for the road traffic noise are as follows: The amount of sound pressure level decrease is 12.6- 14.5dB(A) for first floor when measuring the vertical sound pressure levels at soundproof wall, which indicates a fairly large decrease. At fifth and sixth floor, the amount of decrease is 2.3dB(A), which indicates a small decrease.

담양신설 IC의 교통소음도 조사연구

최형일,강영주,채희정,김연풍,조도호,설동화,정숙경 조선대학교 환경공해연구소 2007 環境公害硏究 Vol.20 No.1

After the vehicle has become a large formation with high-speed, loud noise from an express highway is increasing, and the number of large-scale apartment complexes, which are recently being constructed in the metropolitan area nearby the express highway and IC, is increasing gradually. Compared with a main road, the traffic volume and the speed of a vehicle between IC and the ramp way [turn-off] are smaller. If the ramp way is rightly connected with the downtown area, however, the traffic-noise that comes about in surrounding areas will be in conjunction with the traffic-noise from the main road of express highway and that of the ramp way. This research has selected a place that hasn't had a road or a commercial quarter nearby the main-road of IC and ramp way. Then we have studied the traffic-noise status under minimizing influence of its outer-noise, which occurs in IC. 1. The traffic volume change of a small and full-sized car with time has been kept on regularity in 2004 and 2005. As the traffic volume of a full-sized car has diminished remarkably, it has been maintaining through 6:00a.m.-10:00 a.m. As it has decreased since lO:OO a.m.. we have also observed the traffic proportion going up. 2. Monthly traffic volume of small cars was higher in May, August and October than other months. We have observed that the high traffic volume during these months is due to the following: May-The Damyang festival, August-a high-demand season, October-viewing scarlet maple leaves. Monthly traffic volume of full-sized cars was generally higher in August, but it has decreased during 2006. This was due to the many construction trucks that were working on the extension of the 88 Olympic expressway. Therefore, there was more traffic volume in 2006 compared to 2004 and 2005. 3. In this study, the noise figures have been less than 55 dB(A) in 18 spots. There were 14 spots from 55dB(A) to 58dB(A). 58-61dB(A) : 20, 61-64dB(A) : 17, 64-67dB(A) : 18. There were 8 spots we observed at the highest level from 67dB(A) to 70dB(A). Those were the nearby spots separating the main road and Damyang IC. 4. Traffic-noise at the boundary between IC and the main road of an expressway was higher than that of the same distance in other places. 5. We have observed that traffic-noise is low in places with mountains that serve the role of soundproofing walls. Thus, the fundamental sound hadn't affected it.

월출산국립공원 수질특성에 관한 연구

최형일,김난희,강영주,채희정,김연풍,조도호,설동화 조선대학교 환경공해연구소 2007 環境公害硏究 Vol.20 No.1

Because mountain streams have narrow widths and steep slopes compared to streams and lakes, hours of immobility are considerably short, and the quality of mountain streams has been greatly influenced by rainfall, land-use, components of the streambed and types of forests. During the summer when heavy rainfall occurs, eroded earth and sand flow into mountain streams and cause temporarily high turbidity. It is also the cause of eutrophication, which is frequently found in downstream. As evaluation standards for the quality of mountain streams were not established in Korea, this quality was evaluated by examining some items based on quality standards for drinkable water and research on the influences of pollution in mountain streams, which showed that these were seldom in downstream water systems. Mountain streams within Wolchulsan National Park flow into a reservoir and when characteristics of mountain streams from forests and rainfall that flow into mountain streams through forest ecosystems were studied, results of measuring its changes are as follows. Monthly changes of pH were low between April and August and higher starting October, and the EC was measured higher in the winter and the spring and tended to be low starting April. The EC on the 19th of May and the 23rd of October and the concentration of floating materials and COD_(Mn) were observed to be higher due to the influence of rainfall on the 19th of May and the 22nd of October, and it was judged that the washing out of dried deposits attached to the water pipe and the leaching of woods were influenced by rainfall. It is considered that real-time monitoring of water quality for a long time and water quality conditions during and after rainfall should be examined for ensuring basic data of water quality and evaluating characteristics and seasonableness of mountain streams, which may be greatly changed by artificial influence in the future.