ABSTRACT

ABSTRACT: The height of the main tower of Sutong Bridge is 306 meters and the strength grade of concrete casting cover the steel anchor box is C50.The Elastic Modulus between steel and concrete is different obviously, so the concrete is prone to cracking, thus the pumpability and cracking-resisting of the concrete cause much attention. In this paper, fly ash, hybrid fibers (steel fibers and polypropylene fibers), water content, and polycarboxylic water-reducing agent were used to optimize the mix proportion of concrete.The elementary mechanical properties of concrete including compressive strength, flexural strength, split tensile strength and elastic modulus were investigated and the cracking-resisting property of different concrete mix proportions was tested. The results indicated that the mechanical properties of concrete satisfied the construction requirement, the cracking-resisting property of concrete mixed with hybrid fibers was the best and the optimized concrete was pumped to the height o in site.