车桥耦合振动对新拌混凝土力学性能的影响研究

Research on Vehicle Bridge Coupling Vibration Influence on the Mechanical Properties of Fresh Concrete

采用室内模拟振动对新浇筑混凝土性能的影响,分析行车荷载引起的车桥耦合振动作用对桥梁维修中新浇筑混凝土性能的影响,研究发现:在混凝土凝结初期,不同组合振动对混凝土7 d、14 d和28 d抗压强度都有所提升,而在凝结中期与凝结后期,振动组混凝土抗压强度明显低于静置组,但随着凝期的增长,强度损失有所降低;混凝土抗折强度与劈裂强度对微小裂纹与气孔敏感性较强,不同凝结时期,振动组在抗折强度与劈裂强度均较静置组低,尤其在凝结中期强度值减少明显,两种强度损失率均在8%~14%之间。同时,随着凝期增长,混凝土内部水泥继续进行,对振动产生的微小裂隙有一定"修补"作用,因此,后期抗折强度与劈裂强度损失有所弥补。

Study on the influence of indoor simulated vibration on the performance of fresh concrete, analysis of vehicle bridge coupling vibration caused by vehicle load effect on fresh concrete performance during bridge mainte-nance. The results show that： In the early stage of concrete condensation, the 7 d , 14 d and 28 d compressive strength of concrete with different combined vibration has been improved. But in the middle and late stage of con-densation, the concrete strength in the vibration group was obviously lower than that in the static set group. With the increase of coagulation time, strength loss reduced a bit. The flexural strength and splitting strength of the vibrating group in different coagulation time were decreased for they have strong sensitivity to micro cracks and pores. Espe-cially in the condensed medium, intensity value decreased significantly,the loss rates of the two kinds of strength are all in 8% -14%, Meanwhile,with the growth of coagulation,internal cement in concrete continues to carry on, and certain ＂repair＂ function to the tiny crack of vibration. So,flexural strength and splitting strength loss get a little compensation on later stage.