车桥耦合振动对混凝土早期性能的影响及其损伤机理  

Effects of Vehicle-Bridge Coupled Vibration on Early-Age Properties of Concrete and Its Damage Mechanism

作　　者：蒋正武[1] 任强[1] 袁政成[1] 

机构地区：[1]同济大学先进土木工程材料教育部重点实验室,上海201804

出　　处：《建筑材料学报》2015年第3期471-476,共6页Journal of Building Materials

基　　金：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

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≤0.5MPa）和后期（贯入阻力≥28.0MPa）,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0.5～28.0MPa）,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.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≤0.5MPa）of setting and later age（i.e.penetration resistance≥28.0MPa）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 resistance0.5-28.0MPa）,which may have a great influence on concrete performance.

关 键 词：耦合振动 频率 损伤 机理 

分 类 号：TU528.01[建筑科学—建筑技术科学]