Enhanced damping properties of cement paste containing polyurethane and its improvement mechanism

Abstract

Incorporating polyurethane (PU) in cement paste improved its energy dissipation and damping properties. The damping improvement mechanism of polyurethane cement paste (PUC) was the focus of this research. In the paper, the effects of PU (0%, 5%, 10%, 20%, 30%, and 40%) and w/c (0.35, 0.45, and 0.55) on the static mechanical and damping properties of PUC were investigated. Simultaneously, combining XRD, SEM, and MIP, the microscopic mechanism was also analyzed. The results showed that both the static mechanical strength and storage modulus of PUC were lower than that of the reference group, and the early compressive strength was greatly affected by PU. Meanwhile, the damping capacities of PUC was obviously superior to that of cement paste. Better damping performance was obtained with increasing PU content, while the change of w/c had relatively little effect on PUC. Damping properties of PUC were sensitive to temperature change, and less sensitive to frequency change. Microstructural analysis of PUC showed that no new hydration products were produced due to the addition of PU, but cement hydration was hindered. In addition, the porosity of PUC was significantly increased. All this led to a decrease in mechanical properties. Based on test results, the damping improvement mechanism of PUC was mainly related to the hysteresis effect of PU, porous structure and microstructures in the matrix.