Viscoelastic Cementitious Composites for Controlled Damping of Civil Infrastructure

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This research proposes to develop techniques and guidelines for designing cementitious materials with superior viscoelastic damping capacity. An analytical modeling framework will be created for guiding the multiscale design of customized, controlled viscoelastic cementitious composites. Based on the analytical models, the new design techniques will utilize strategic integration of materials science and mechanics to optimize damping on multiple length scales. On the nano through microscale, the poromechanical behavior of cementitious materials will be exploited to utilize apparent viscoelastic properties to promote hydraulic damping; this effect is analogous to the mechanism of a shock absorber in that damping will be provided by compressed viscous fluid flowing through small pores. In cementitious materials, the pore fluid will be forced through the designed, interconnected pore network to invoke hydraulic damping. On the millimeter scale, novel viscoelastic inclusions with model driven surface conditioning will be utilized to improve composite damping. Experiments will be performed to measure parameters critical to the analytical models, and to validate the model predicted damping. Critical parameters to measure will include traditional properties such as porosity, pore interconnectivity, and moduli, as well as nontraditional properties such as surface energy.If successful, the results of this research will enable the development of exciting new tailored viscoelastic cementitious composite materials for civil infrastructure applications. The primary role of these new materials will be to serve as integrated energy absorbers to reduce the damage induced by earthquakes, wind, impacts, blasts, and other sources of structural vibrations. The contribution of structural materials to damping may be considerable, owing to the tremendous volume of such materials in a structure. Additionally, this research will result in an overall improvement in the understanding of the behavior of viscoelastic porous solids, phase interaction in composite materials, and fluid-solid material interaction.