| Title |
A Study on the Mechanical Properties of Ultra High-strength Concrete According to the Concurrent Placement of Vertical and Horizontal Members |
| Authors |
Lee Keun-Bae ; Kim Seong-Deok ; Baek Min-Su ; Jung Sang-Jin |
| Keywords |
V.H Seperated Placement ; V.H Concurrent Placement ; Ultra High Strength Concrete |
| Abstract |
The vertical-horizontal separated placement method (V.H. separated placement method) is being widely used for high-rise buildings as well as for general buildings. The V.H. separated placement is advantageous in that the placement is easy, e.g., using vibrating compaction, because there is no interference of slab reinforcements in the case of concrete placement for columns, and that it allows forms to be easily removed and used for the next placement section. Despite the advantages of the V.H. separated placement, the V.H. concurrent placement is used in korea to reduce the construction period, which has the self compaction property and a high viscosity that prevents segregation. In this study, the basic data for concurrent placement of the high-strength concrete, including the transport properties, the strengths of members by height, and the hydration properties, were presented with concrete specimens with different strengths. The curing methods and core strengths for members in different locations met the targeted strengths, which were 60 MPa, 80 MPa and 100 MPa, at the given aging level. The core strength increased with aging. High increase in the strength was observed especially on the lower parts of the beams and columns. As for the strength of the core by height, the strength was higher on the middle and upper sections than on the lower sections, though the differences were not significant. With the increase in the targeted strength, the peak hydration temperature was reached in a shorter time, and the temperature difference between the center and surface of the specimen was about 15℃ for each strength value. |