마이크로웨이브와 염산/과산화수소를 이용한 순환골재의 부착 모르타르 제거 메커니즘 및 반응 특성

초록

This study aimed to describe the mechanism and reaction characteristics of the adhered mortar removal of recycledaggregate (RA) using microwave irradiation (700 W) and a mixed solution of HCl and H2O2. The HOCl concentrationincreased to 29.7 M at 35oC and 40 min of reaction time without RA in the mixed solution, which shows that HCl reactswith H2O2 to form HOCl and water. However, after nitrogen purging, the HOCl concentration decreased to 2.71 M in20 min, which proves indirectly that HOCl reacts with HCl to form Cl2 and water. The HOCl concentration decreasedfrom 29.7 M to 1.88 M at 35oC in 40 min with RA in the mixed solution, and the Ca2+ concentration increased to 9,750mg/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 areaction temperature of 50oC was about 1.3 times faster than that at 35oC. The treated RA was improved in density, waterabsorption, abrasion loss, and absolute volume.

키워드