Title |
A Fundamental Study on the Hydration Heat Reduction of Transfer Girder Mass Concrete Controlling Setting Time |
Keywords |
Super Retarding Agent ; Setting Time ; Temperature History ; Hydration Heat ; Mass Concrete |
Abstract |
This paper presents hydration heat reduction method of mass concrete using setting time deference method. Four different small scaled specimens were fabricate to investigate the temperature history. The test results showed that the use of SRA did not affected the properties of fresh concrete, but SRA delayed final setting time of fresh concrete by as much as above 48 hours. For the properties of temperature history of hydration heat, conventional concrete exhibited dramatical temperature rising with age and then created temperature cracks, due to the remarkable difference of temperature between surface and center of mass concrete. However, mass concrete specimen 'B', which contained 0.3% of super retarding agent, decreased crack index, This can be explained by the fact that hydration heat of surface was higher than that of center. In addition, although hydration heat of specimen 'C' had the lowest peak temperature, severe temperature crack was observed at bottom section. This means that C method is not valid for transfer girder. The concrete cured in standard condition exhibited increased compressive strength, with increase of SRA dosage, compared with conventional concrete while core compressive strength had comparable result with conventional concrete, regardless of SRA dosage. It is clarified that use of SRA had not influence on compressive strength. |