九江长江公路大桥超宽箱梁C55粉煤灰高性能混凝土配合比设计

摘要

Aiming at concrete mixture proportion design for super-wide box girder of Jiujiang Yangtze River Expressway Bridge, the effect of fly ash amount, water-binder ratio and sand- total aggregate ratio on physical and mechanical properties of the box girder C55 high performance concrete (HPC) has been investigated. The results show that the box girder C5S HPC mixture prepared from P · Ⅱ 42.5 cement and 25 % grade Ⅰ fly ash possess good workability, high early strength and great growth of late strength as well as high resistance to chloride ion penetration, with 0.305 water-binder ratio and 39 % sand-total aggregate ratio. Especially the low adiabatic temperature rise is good to improve the crack resistance of box girder concrete.%针对九江长江公路大桥超宽箱梁混凝土的配合比设计,研究了粉煤灰掺量、水胶比、砂率等参数对箱梁C55高性能混凝土物理力学性能的影响.结果表明:采用42.5 P·Ⅱ水泥掺入25％Ⅰ级粉煤灰,水胶比0.305、砂率39％的箱梁C55高性能混凝土具有良好的工作性,较高的早期强度和较大的后期强度增长,很高的抗氯离子渗透性；特别是具有较低水化热温升,有利于改善箱梁混凝土的抗裂性.