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Title |
Thermal Conductivity and Pore Characteristics of Low-Temperature Sintered Lightweight Aggregates Made from Waste Glass and Bottom Ash
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Keywords |
경량골재 ; 폐유리 ; 바텀애쉬 ; 열전도율 lightweight aggregate ; waste glass ; rottom ash ; thermal conductivity |
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Abstract |
In this study, waste glass and bottom ash were used as basic materials in order to secure a recycling technology of by-products which was mostly discarded and reclaimed. In addition, because softening point of waste glass is less than 700oC and bottom ash includes combustible material, it was possible to manufacture low-temperature sintering lightweight aggregates for energy saving at 800~900oC that it is as much as 20~30% lower than sintering temperature of existing lightweight aggregates. Thermal conductivity of newly-developed lightweight aggregates was 0.056~0.105W/m. K and its porosity was 40.36~84.89%. A coefficient of correlation between thermal conductivity and porosity was ?0.97, it showed very high negative correlationship. With this, we were able to verify that porosity is key factor to affect thermal conductivity. Microstructure of lightweight aggregates by CaCO3 content and replacement ratio of bottom ash in the variation of temperature were that CaCO3 content increased along with pore size while replacement ratio of bottom ash increased as pore size decreased. Specially, most pores were open pore instead of closed pore of globular shape when replacement ratio of bottom ash was 30%, and pore size was small about 1/10~1/5 as compared with case in bottom ash 0~20%. In addition, open pore shapes were remarkably more irregular form of open pore in 900oC than 700oC or 800oC when replacement ratio of bottom ash was 30%. We reasoned hereby that these results will influence on absorption increase, strength and thermal conductivity decrease of lightweight aggregates.
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