Papers by Author: Sang Wook Ha

Abstract: The effectiveness of bottom ash on the mechanical and physical properties of lightweight cement mortar for fire proofing application is investigated in this study. Bottom ash is well known that it can make it possible to decrease the thermal conduction in mortar by their porous structure. Physical properties of bottom ash including pozzolanic activity and compressive strength test were measured to decide the replacement amount in formulation as well as chemical composition. This study was undertaken on the use of bottom ash as fine aggregate in fire proofing mortar. Various dosage of bottom ash such as 25%, 50%, 75%, 100% were evaluated by several measurement. We found out there were serious correlation between specific gravity and thermal conductivity, so other porous materials were also investigated to decrease the thermal conductivity of cement mortar as well as bottom ash. In this study, the researches on the mixing proportion were mainly performed to design specification of spraying fire proofing mortar. Based on the laboratory test results, we’d like to suggest the proper adding amount of bottom ash by evaluation of consistency and strength development and then optimum mixing proportions of spraying fire proofing mortar using bottom ash by various evaluations.

Abstract: In this work, the physical & chemical properties of bottom ash generated from power plant are analyzed. Characteristic mortar property and thermal conductivity for building material were investigated with content of added bottom ash. According to the analytic result of bottom ash, chemical compositions of bottom ash is similar to those of fly ash and compressive strength after 7days related to pozzolanic activity shows 2.5N/cm2 and it is confirmed that bottom ash possess a certain amount of moisture activity. Although the fluidity of cement mortar is rapidly decreased with increasing addition of bottom ash, compressive strength for 3 and 7days is increased. The thermal conductivity is not sensitive to the addition of bottom ash.

Abstract: The effects of the pair-minerializer (CaSO4,-CaF2) on the burnability of clinker and the formation of mineral are investigated. As experimental results, the addition of F as pair-mineralizer, the burnability of clinker was improved. Especially, the addition of F and SO3 components simultaneously as pair-mineralizer, total amount of free lime in clinker is rapidly decreased compared with the value which mineralizer was added separately. In case of adding K2O only to the raw mixes, the amount of free lime is increased. However, if alkali (K2O) and pair-minerializer (CaSO4,-CaF2) were added simultaneously, the produced amount of clinker mineral is increased due to the formation of stable calcium langbeinite by the combination of alkali (K2O) and sulfate