中文摘要：

利用自主开发的三点弯曲梁阻尼测试装置对不同掺量纳米SiO2混凝土的阻尼性能进行了测试,通过X射线衍射仪和扫描电镜研究了不同掺量纳米SiO2对混凝土微观结构的影响,并对其阻尼增强机理进行了初步探讨。结果表明纳米SiO2掺量为4%时混凝土材料的损耗因子最大,为素混凝土的2.41倍,综合考虑成本、流动性、强度和阻尼等因素确定纳米SiO2的最优掺量为3%;纳米SiO2掺入混凝土中后,与之发生二次水化反应,使得混凝土中六方板状Ca（OH）2晶粒数量减少;纳米SiO2对于混凝土的阻尼增强机理在于纳米SiO2的掺入使得混凝土材料的内接触面数量增多,在外力作用下使应力不均匀分布增加,从而提高了材料摩擦阻尼耗能的能力。

英文摘要：

Damping in structures is commonly provided by viscoelastic nonstructural materials.Due to the large volume of structural materials in a structure,the contribution of a structural material to damping can be substantial.In this paper,the experimental investigation on damping ability of concrete materials and its members with nano-SiO2 was carried out by the method of 3-point bending beam damping measurement and cantilever beam free vibration respectively.The microstructure of concrete mix with nano-SiO2 was observed by XRD and SEM,then damping mechanism was discussed.The experimental results show that the damping reinforced effect achieved best with the 4% mixture ratio of nano-SiO2,but the optimal adulteration quantity of nano-SiO2 was 3% of cement weight by the comprehensive consideration of cost,workability,strength and dynamic properties.Nano-materials as a mixture increase interfaces,and the non-uniform stress distribution under external force improves frictional damping energy consumption ability of concrete.The experimental results on the damping ratio and the loss tangent of the concrete materials with nano-materials are consistent.