| 摘要: |
| 在分析车桥耦合振动参数变化规律的基础上，提出了合理的振动模拟试验方法与评价指标，研究了车桥耦合振动参数对不同水胶比混凝土性能的影响，并结合微观结构试验结果，探讨了混凝土损伤机理.研究发现：车桥耦合振动会加速混凝土的泌水，降低实际水胶比，一定程度上有利于其抗压强度测试值的提高，但会提高混凝土内部大于200nm的多害孔比例，同时加剧石子下沉和浆体上浮，使得混凝土早期离析程度增大，均匀性降低，密实度降低，从而降低混凝土长期性能.在混凝土凝结硬化初期(贯入阻力≤05MPa)和后期(贯入阻力≥280MPa)，车桥耦合振动产生的破坏作用较小；在凝结硬化中期(贯入阻力为05～280MPa)，车桥耦合振动会导致混凝土内部产生永久微裂纹等缺陷，对混凝土性能影响较大. |
| 关键词: 耦合振动 频率 损伤 机理 |
| DOI：103969/j.issn1007 9629201503019 |
| 分类号: |
| 基金项目:国家重点基础研究发展计划(973计划)项目(2011CB013805)；国家自然科学基金资助项目（51478348，51278360，51308407）；“十二五”国家科技支撑计划项目（2014BAL03B02）；高等学校博士学科点专项科研基金资助项目(20130072110047)；上海市科委重点项目(14DZ1202302）；中央高校基本科研业务费专项资金资助 |
|
| Effects of Vehicle Bridge Coupled Vibration on Early Age Properties of Concrete and Its Damage Mechanism |
|
JIANG Zhengwu, REN Qiang, YUAN Zhengcheng
|
|
Key Laboratory of Advanced Civil Engineering Materials of Ministry ofEducation, Tongji University, Shanghai 201804, China
|
| Abstract: |
| The variation law of vehicle bridge coupled vibration was analyzed and a reasonable method to simulate coupled vibration in lab as well as the evaluation indexes was proposed. Then the effects of vehicle bridge coupled vibration parameters on the properties of concrete with different water cement ratio were studied. The damage mechanism of vehicle bridge coupled vibration on concrete was investigated according to the microstructure results. The results indicate that under vehicle bridge coupled vibration, the bleeding of concrete accelerates, the actual water cement ratio reduces, and the compressive strength increases to a certain extent. However, the early segregation of concrete is aggravated by the vibration, which leads to worse uniformity and compactness. The long term performance of concrete is deteriorated as seen from a higher proportion of deleterious pores (>200nm) of concrete. At the early age (i.e. penetration resistance≤05MPa ) of setting and later age(i.e. penetration resistance≥280MPa) of hardening, the negative interference of vehicle bridge coupled vibration is insignificant, however, vehicle bridge coupled vibration can lead to a lot of irreversible micro cracks in concrete at the middle age (i.e. penetration resistance 0.528.0MPa), which may have a great influence on concrete performance. |
| Key words: coupled vibration frequency damage mechanism |
