건설폐기물 발생량이 매년 급격히 증가함에 따라 건설폐기물 처리의 중요성이 점차 심화되고 있으며, 그 중에서도 가장 많은 비중을 차지하고 있는 폐콘크리트의 처리에 가장 많은 노력을 기울이고 있다. 현재 폐콘크리트는 단순 파쇄를 통해 매움재나 채움재 등의 저급한 용도의 순환골재로 재활용되고 있다. 그러나 부족한 구조용 골재 수급문제를 해결하고 자원의 효율적인 활용을 위해서, 천연골재를 대체하여 구조용 골재로 사용될 수 있는 고품질의 순환골재 생산이 절실히 요구되고 있다. 따라서 본 연구에서는 autogenous mill과 가열처리 방법을 이용하여 고품질 순환골재 생산 공정을 개발하였다. 개발된 공정을 이용하여 약 30분간 파분쇄과정을 통해 생산된 순환골재의 품질은 밀도 $2.5\;g/cm^3$이상, 흡수율 3% 이하로 KS F 2573의 1종 굵은 순환골재 품질 기준을 만족하였으며, 이를 바탕으로 고품질의 순환골재 생산을 위한 연속공정을 개발하였다.
건설폐기물 발생량이 매년 급격히 증가함에 따라 건설폐기물 처리의 중요성이 점차 심화되고 있으며, 그 중에서도 가장 많은 비중을 차지하고 있는 폐콘크리트의 처리에 가장 많은 노력을 기울이고 있다. 현재 폐콘크리트는 단순 파쇄를 통해 매움재나 채움재 등의 저급한 용도의 순환골재로 재활용되고 있다. 그러나 부족한 구조용 골재 수급문제를 해결하고 자원의 효율적인 활용을 위해서, 천연골재를 대체하여 구조용 골재로 사용될 수 있는 고품질의 순환골재 생산이 절실히 요구되고 있다. 따라서 본 연구에서는 autogenous mill과 가열처리 방법을 이용하여 고품질 순환골재 생산 공정을 개발하였다. 개발된 공정을 이용하여 약 30분간 파분쇄과정을 통해 생산된 순환골재의 품질은 밀도 $2.5\;g/cm^3$이상, 흡수율 3% 이하로 KS F 2573의 1종 굵은 순환골재 품질 기준을 만족하였으며, 이를 바탕으로 고품질의 순환골재 생산을 위한 연속공정을 개발하였다.
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 r...
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.
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.
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제안 방법
Tests were conducted using a single size fraction (75 mmx53 mm) to investigate the degree of breakage by the autogenous mill. The size distribution and physical characteristics, density and adsorption ratio, were analyzed for the milling products every 10 minutes.
the autogenous mill. The size distribution and physical characteristics, density and adsorption ratio, were analyzed for the milling products every 10 minutes. Using these results, locked-cycle circuit tests were conducted.
Therefore in this study, the samples were heated in an oven for 1 hour at 400℃. The test results were compared with results without heat treatment to evaluate the effect of heat treatment.
Besides, environmental destruction from excavation of natural aggregate is prevented. Therefore, in this study, tests were conducted to develop an advanced processing circuit for production of high quality recycled aggregates, which involves heat-pretreatment and autogenous milling.
processing circuit. To evaluate the heat treatment method, the tests were performed equally using samples with and without heat pretreatment samples.
Using the above test results, a continuous breakage test was conducted to develop a recycled aggregate producing circuit. After 30 minutes of milling, the -26.
Milling time was increased from 10 minutes to 30 minutes, and the quality of produced recycled aggregate was analyzed at each cycle of 30 minute milling. Using the test results, a continuous circuit test for recovery of recycled aggregate was conducted.
The size distribution and physical characteristics, density and adsorption ratio, were analyzed for the milling products every 10 minutes. Using these results, locked-cycle circuit tests were conducted. After 10 minutes of milling, the products were separated at a certain size, which was determined by the physical characteristics of the milling products.
대상 데이터
Concrete waste used in this study was the product of a primary jaw crusher (200 ton/h) installed at a waste concrete processing plant. Currently, construction and demolition waste are not collected separately in Korea, so the concrete waste collected to the concrete waste processing plant is not homogeneous, because it was containing a complex mixture of concrete blocks, asphalt wastes, wood wastes etc.
The autogenous mill used in this study has a mill chamber with a diameter of 710 mm and a length of 530 mm and has a 1 lifter with a height of 100 mm inside the mill chamber. The rotation speed is fixed at 30 rpm and the percentage of mill volume occupied by the sample is 10%, which is about 48.
이론/모형
An advanced continuous circuit for producing high quality recycled aggregates was developed in this study using a heat pretreatment method and autogenous milling. Using a primary jaw crusher product, heat treatment was conducted and crushed using an autogenous mill.
성능/효과
The quality of crushed product after 3 times of processing circuit from the continuous test met the specifications of the first class of KS F2573 (Table 4), indicating that high quality recycled coarse aggregate could be produced from this circuit. Therefore, the circuit developed in this study using an autogenous mill, heat treatment, and size classification was valid and was found to be efficient for producing high quality recycled coarse aggregates.
참고문헌 (9)
Hun Do Lee, 2006 : Project for the recycling technology development of construction waste, Proc. of Korea-Japan International Symposium for construction waste recycling policy and technology, pp. 61-78, Housing and Urban Researching Institute, 2 June 2006, Seoul Korea
2005, Environmental Statistics Yearbook, pp1-33, Ministry of Environment Republic of Korea
Amnon Katz, 2003 : Properties of concrete made with recycled aggregate from partially hydrated old concrete, Cement and Concrete Research, 33, pp.703-711
Andrzej Ajdukiewicz and Alina Kliszczewicz, 2002 : Influence of recycled aggregates on mechanical properties of HS/HPC, Cement and Concrete Composites, 24, pp.269-279
C. S. Poon. et al. 2004 : Influence of moisture states of natural and recycled aggregates on the slump and compressive strength of concrete, Cement and Concrete Research, 34, pp.31-36
A. Gokce. et al. 2003 : Freezing and thawing resistance of air-entrained concrete incorporating recycled coarse aggregate: the role of air content in demolished concrete, Cement and Concrete Research, 34, pp.799-806
Ji Whan Ahn, Hyung Seok Kim, Gi Chun Han, 2001 : Recovery of aggregate from waste concrete by heating and grinding, Geosystem engineering, 4(4), pp.123-129
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