This study aimed to describe the mechanism and reaction characteristics of the adhered mortar removal of recycled aggregate (RA) using microwave irradiation (700 W) and a mixed solution of HCl and H2O2. The HOCl concentration increased to 29.7 M at 35oC and 40 min of reaction time without RA in the mixed solution, which shows that HCl reacts with H2O2 to form HOCl and water. However, after nitrogen purging, the HOCl concentration decreased to 2.71 M in 20 min, which proves indirectly that HOCl reacts with HCl to form Cl2 and water. The HOCl concentration decreased from 29.7 M to 1.88 M at 35oC in 40 min with RA in the mixed solution, and the Ca2+ concentration increased to 9,750 mg/L, which demonstrates indirectly that mortar mainly composed of Ca(OH)2 reacts with Cl2 to form Ca(OCl)2 and CaCl2. The reaction rate (k) with microwave heating was about 2.3 times faster than that with conventional heating, and k at a reaction temperature of 50oC was about 1.3 times faster than that at 35oC. The treated RA was improved in density, water absorption, abrasion loss, and absolute volume.

Abstract
 I. 서 론
 II. 이론적 고찰
 III. 실험계획 및 측정방법
  1. 마이크로웨이브 조사가 모르타르 제거에 미치는 영향
  2. 반응온도에 따른 모르타르 제거 및 HOCl 농도 변화
  3. 질소 주입을 통한 HOCl 농도 측정
  4. 모르타르 제거에 따른 칼슘 농도
  5. 차아염소산나트륨을 이용한 HOCl 생성 및 모르타르제거 반응
  6. 물리적 성상 변화
   6.1. 절대건조밀도 및 흡수율
   6.2. 마모감량
   6.3. 실적률
 IV. 결과 및 고찰
  1. 모르타르 제거특성
   1.1. 마이크로웨이브 및 일반가열 방법의 모르타르 제거속도 비교
   1.2. 반응온도에 따른 모르타르 제거 및 HOCl 농도
   1.3. 질소 주입에 따른 HOCl 농도 변화
   1.4. 모르타르 제거에 따른 칼슘 농도
   1.5. 차아염소산나트륨을 이용한 HOCl 생성 및 모르타르 제거 반응
  2. 반응 후 순환골재 특성
   2.1. 절대건조밀도 및 흡수율
   2.2. 마모감량
   2.3. 실적률
 V. 결 론
 감사의 글
 References

• 변민우(강원대학교 환경공학과, Department of Environmental Engineering, Kangwon National University) | Min-Woo Byeon
• 김정원(한림대학교 환경생명공학과, Department of Environmental Biology Engineering, Hallym University) | Jung Won Kim
• 안종화(강원대학교 환경공학과, Department of Environmental Engineering, Kangwon National University) | Johng-Hwa Ahn Corresponding author