Influence of bridge dynamic effects on ultra high performance concrete with coarse aggregate
丁庆军 1周昌盛 1郭凯正 1龚金华 1雷宇翔1
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作者信息
1. 武汉理工大学硅酸盐建筑材料国家重点实验室,湖北武汉 430070
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摘要
为解决粗骨料超高性能混凝土(UHPC)在桥梁工程可能遭受的桥梁动力效应问题,通过小型振动台进行模拟桥梁振动,以振动幅度和频率为振动参数,研究了桥梁振动对粗骨料UHPC的力学性能、超声波波速及粗骨料沉降系数的影响规律.试验结果表明:1 mm的振动幅度可以有效改善孔结构,对粗骨料UHPC的力学性能和超声波波速具有促进作用;当振动幅度大于1 mm时振动会引入内部缺陷,并且粗骨料离析程度增大,刚性骨架被破坏,抗压强度、弹性模量和超声波波速降低;当振动频率增大时,能够有效改善钢纤维与基体的黏结性能,增强粗骨料UHPC的弯曲韧性;在实际粗骨料UHPC用于桥梁施工过程中应注意控制桥梁振动幅度,不应超过3 mm.
Abstract
In order to solve the problem of bridge dynamic effect that ultra-high performance concrete(UHPC)with coarse aggregate may suffer in bridge engineering,bridge vibration was simulated by a small shaking table,and the influence of bridge vibration on mechanical properties,ultrasonic wave velocity and sedimentation coefficient of UHPC with coarse aggregate was studied with vibration amplitude and frequency as vibration parameters.The experimental results show that the vibration amplitude of 1 mm can effectively improve the pore structure and promote the mechanical properties and ultrasonic wave velocity of UHPC with coarse aggregate.When the vibration amplitude is greater than 1 mm,the vibration will introduce internal defects,and the segregation degree of coarse aggregate will increases,the rigid skeleton will be destroyed,and the compressive strength,elastic modulus and ultrasonic wave velocity will decrease.When the vibration frequency increases,the bonding property between steel fiber and matrix can be effectively improved,and the bending toughness of UHPC with coarse aggregate can be enhanced.In the actual application of UHPC with coarse aggregate in bridge construction,attention should be paid to controlling the vibration amplitude of the bridge,which should not exceed 3 mm.
关键词
桥梁振动/振动参数/粗骨料超高性能混凝土/力学性能/损伤机理
Key words
bridge vibration/vibration parameters/ultra high performance concrete with coarse aggregate/mechanical property/damage mechanism
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