Fire Resistance Performance of High Strength Concrete Columns with Fireproof Mortars Using Cement and Gypsum

시멘트 및 석고계 내화모르타르를 피복한 고강도콘크리트 기둥의 내화성능

By coating surface of high strength concrete with fireproof mortar, the high strength concrete is protected from the spalling in fire and the method to constrain the temperature increase of steel bar within the concrete. The purpose of this study is to investigate fire resistance performance of the high strength concrete coated with fireproof mortar using gypsum or cement exposed to fire. As a results, it were found that the high strength concrete column coated with fireproof mortar using cement and gypsum could be suited to fire resistance performance management standard of MLTM, and the explosive spalling of high strength under fire was remarkedly affected by the size of column. In this study, the specimens with 50mm cover depth of reinforced bar, which were larger size than those with 40mm cover depth of reinforced bar, spalled and were not suited to fire resistance performance management standard of MLTM regardless of type of fireproof mortar. It can also be concluded that fireproof mortar using cement and gypsum seems to have a integrity problem under fire, which needs to be addressed before it can be applied where explosive spalling of high strength concrete is of importance.