The State Flagpole which is built in Baku, the capital of Azerbaijan can be compared with other biggest flagpole strcutures in the World. The length of flagpole is 175 m. In reconstruction period under flagpole there will be built reinforced-concrete pilecap which will stay on the 53 piles. These pile were buried -35.00 m deep and their diameter is 1500 mm. The hieght of the pilecap is 8,5 m and this will be built with 10 different concrete classes. And 2,5 m of the pilecap is under the ground. The octagonal part where the ø5700 mm flagpole will be located. will be done by using ultra-high strength concrete of class B105.
Wind load, landslides and subsidence, bending and overturning moments resulting from seismicity act on flagpole then pilecap and then to foundation part.
In investigation process of B105 class ultra-high strength concrete there were done additional laboratory tests. First we choose 62,5 MPa high activity Holcim cement and use 530 kg/m3 of it in concrete. For getting ultra-high strength and self-compacting concrete we also use 40 kg/m3 microsilica and additive Glineum 313 (1,8%). This additive makes concrete to strengthen late. To decrease water resistance we use powder of D-5 additive. There also used 3% (15,9 kg/m3) Master Builders 506 hyperplasticizator.
The higher the compression resistance the lower the elasticity of the ultra-high strength concrete will be. Concrete become less crack resistant. In order to avoid tensile forces and surface cracks on concrete we have to add steel fibers to it [1].
There were prepared ultra-high strength concrete examples at the test site of Construction Material Research Institute. There were tested compressive strength of 150x150x150mm concrete cubes. Cubes were tested by using ultrasonic and hydraulic test method. To increase tensile resistance there also were used fiber additives. As fiber additive we used Turkish “Kemerix” 3D typed fiber 30kg/m3. There were done spitting test to determine tensile forces of fiber concrete examples. Beside that there also were done frost resistance, water absorption and water resistance tests. Frost resistance class was appointed F100 and water resistance class was appointed W12. To increase concrete strength and crack resistance we used hyperplasticizator and microsilica and as a results we got plastic fluid concrete.
There were studied the connection of steel flange to the top of the reinforced-concrete pilecap and stress-strain state of the octagonal reinforced-concrete plate which were modeled in computer.
Anahtar Kelimeler: ultra-high strength, self-compacting, fiber concrete, compressive strength
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