Experimental Research And Application Of High Damping Concrete In Structural Energy Dissipation And Vibration Mitigation

The vibrations due to earthquakes, winds and explosive loads belong to random external broad spectrums, therefore the existing means of earthquake resistance and vibration mitigation by changing the periods of structures are restricted in validity. Enhancing the structural damping will be an inevitable way in the future. Currently, the damping of structures is increased mostly by appending damping installations. And the research on enhancing the damping characteristics of structures through improving the damping property of materials is seldom reported.The polymer concrete has been put forward for many years ago, but only used in the areas of leakage prevention and reparation etc. The polymer concrete has not been used as structural material due to the fact that the adding of polymer decreases the strength and stiffness of the concrete. Focusing on the polymer concrete, this paper strives to resolve the contradiction between the strength and the damping property of normal concrete, by changing the amount of polymer and adding the fillings such as fiber, silicon powder and graphite. The advices on the method of applying the high damping polymer concrete in real structures are proposed.The primary contents of this research are as follows:1, By changing the amount of polymer, studying the effect of polymer on the dynamic elastic modulus, compressive strength and damping ratio of concrete, and finding the optimal amount of polymer to achieve the high damping characteristics for normal concrete.2, Based on the optimal amount of polymer, obtaining a kind of high damping concrete, that is capable of bearing and transferring the loads required for a structural material, by adding the fillings such as fiber, silicon powder, graphite and so on.3, A test system used to measure the damping ratio of the material was set up, and its reliability was verified.4,The damping mechanisms of styrene butadiene latex, silicon powder and graphitewere investigated.5, The application method of high damping concrete in structures was investigated.6, The dynamic responses of normal concrete structure, local high damping concrete structure and entire high damping concrete structure were simulated by using ANSYS.Test results show that the adding of styrene butadiene latex increases significantly the damping property of concrete, but decreases the strength of concrete. However, the adding of silicon powder can offset the loss of concrete strength due to polymer in some way. Graphite can complement the damping property of concrete. It is concluded that the optimal mixture ratio of filling to cement is 13 percent for styrene butadiene latex, 8 percent for silicon powder and 5 percent for graphite. The high damping concrete based on the optimal ratio of fillings maintains 70% of the compressive strength of the corresponding normal concrete, but achieves nearly twice as much the value of damping ratio as the corresponding normal concrete. The results of simulation analysis show that high damping polymer concrete obtained from experiments improves the dynamic characteristics of concrete structures effectively. In harmonic analysis, title dynamic responses of the high damping concrete structure are reduced by 50%, compared with the normal concrete structure.