Poromechanical Damping of Cementitious Materials

Other than through the creation of fracture surfaces, cementitious materials do not generally contribute significantly to strain energy dissipation or damping during dynamic loading of civil infrastructure. In this paper, the potential to increase damping of cementitious materials through utilization of poromechanical effects is evaluated. Pervious cement paste and mortar specimens were fabricated and their uniaxial damping measured at loading frequencies ranging from 0.01–25 Hz. To evaluate the poromechanical effect, the damping of specimens with water, glycerol, and glycerol/water blends constituting the pore fluid was measured, and the results were compared with the measured damping of dried specimens. It was found that significant poromechanical damping can be generated in cementitious materials, and the frequency at which the damping is maximized can be controlled by changing material properties that dictate the hydrodynamic relaxation time. It was also discovered that poromechanical modeling under predicts the measured damping increase induced by saturating porous concrete, indicating that the degree of saturation influences the inherent viscoelastic damping of cementitious materials.