13 mm이하 순환 굵은골재 치환사용에 의한 연속입도 콘크리트의 공학적 특성 = Engineering Properties of Well-graded Concrete Replaced with Recycled Coarse Aggregate with Less than 13 mm in Size

다국어 초록 (Multilingual Abstract)

In this research, as a solution of environmental load and exhaust of natural resources due to the increased construction wastes, the recycled aggregate extracted from building waste is sieved for 13 mm size aggregate and replaced to 13 to 25 mm manufactured coarse aggregate to obtain well-graded aggregate conditions. Using this aggregate, the method for securing favorable properties of concrete is suggested. The result of a series of the experiment is as follow.
(1) The plain concrete without replacement of 5-13 mm recycled coarse aggregate used the aggregate with less fines although it could be passed KS standard gradation. Hence, it was known that replacing 5 to 13 mm of recycled aggregate is necessary to supply fines and achieve good gradation.
(2) For the workability of the concrete, when the concrete contained the aggregate replaced 5 to 13 mm of recycled coarse aggregate, the workability was improved. Especially, about 30 % of 5 to 13 mm recycled coarse aggregate replacement showed better workability than the concrete without replacement of 5 to 13 mm recycled coarse aggregate. Although the gradation of aggregate used was well-graded, over the threshold of 30 % of replacement, decreased workability was observed.
(3) For the air content of the concrete mixtures, regardless of water-to-cement ratio, as the replacement ratio of 5 to 13 mm recycled coarse aggregate is increased, the air content of the concrete mixture was decreased. It is considered that the decreased the volume of voids due to the well-graded aggregate with replacement. On the other hand, over 50 % of replacement of 5 to 13 mm recycled coarse aggregate caused increased air content of the concrete mixture because of increased air voids. In the case of unit weight, regardless of water-to-cement ratio, the values were changed related with the amount of air in the concrete mixtures. In the case of 100 % replacement of 5 to 13 mm of recycled coarse aggregate, however, decreased unit weight was obtained because of lighter density of recycled aggregate than the density of manufactured aggregate.
(4) The compressive strength of the concrete mixture replaced 5 to 13 mm recycled coarse aggregate was increased due to the well-graded aggregate and thus densely filled microstructure. Especually, when the 5 to 13 mm of recycled coarse aggregate was replaced 30 %, the highest compressive strength was achieved and this value was similar to the concrete replaced with 5 to 13 mm of manufactured coarse aggregate.
In the case of drying shrinkage, although there was no significant difference, recycled aggregate replacement contributed decreasing drying shrinkage.
In summary, replacing the recycled coarse aggregate of 5 to 13 mm of size for 30 %, a good grade of aggregate was achieved and thus general quality improvement and financial advantages were obtained. Additionally, as increasing the utilization of recycled aggregate, it is expected to contribute on providing the solution of reducing environmental load and the method of preferred quality of concrete with low cost.

목차 (Table of Contents)

• 1. 서 론 1
• 1.1 연구배경 및 목적 1
• 1.2 연구범위 및 방법 2
• 1.3 연구동향 5
• 2. 이론적 고찰 7
• 2.1 골재의 개요 7
• 2.1.1 정의 및 역할 7
• 2.1.2 골재의 분류 7
• 2.1.3 골재의 품질 10
• 2.2 순환골재의 개요 및 품질특성 19
• 2.2.1 순환골재의 정의 19
• 2.2.2 순환골재의 특성 20
• 2.2.3 순환골재의 밀도 및 흡수율 21
• 2.2.4 순환골재의 입형 및 입도 22
• 2.2.5 순환골재의 품질기준 23
• 2.3 순환골재의 생산 31
• 2.3.1 순환골재의 생산 및 사용 현황 31
• 2.3.2 건설폐기물 발생현황 32
• 2.4 순환골재가 콘크리트 품질에 미치는 영향 35
• 2.4.1 굳지 않은 콘크리트에 미치는 영향 35
• 2.4.2 경화 콘크리트에 미치는 영향 37
• 3. 실험계획 및 방법 39
• 3.1 실험계획 39
• 3.2 사용재료 41
• 3.2.1 시멘트 42
• 3.2.2 골재 42
• 3.2.3 혼화재료 44
• 3.3 실험방법 44
• 3.3.1 콘크리트의 혼합 44
• 3.3.2 사용재료 45
• 3.3.3 굳지 않은 콘크리트 47
• 3.3.4 경화 콘크리트 49
• 4. 실험결과 및 분석 53
• 4.1 입도분급 순환 굵은골재의 입자특성 53
• 4.2 굳지 않은 콘크리트의 특성 58
• 4.2.1 슬럼프 58
• 4.2.2 공기량 61
• 4.2.2 단위용적질량 64
• 4.3 경화 콘크리트의 특성 67
• 4.3.1 압축강도 67
• 4.3.2 건조수축 길이변화율 75
• 4.4 종합분석 78
• 4.4.1 콘크리트 품질의 비교분석 78
• 4.2.2 콘크리트의 단가 비교 81
• 5. 결 론 83
• 참 고 문 헌 85
• ABSTRACT 89