Improving the damping ability by the addition of nano-SiO₂ to the concrete materials

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.