- Improvement in mechanical damping of cementitious materials incorporating viscoelastic inclusions has been evaluated. Specimens were fabricated and tested with cyclic uniaxial compressive loading at frequencies of 0.2-25 Hz. Significant improvement in damping was observed in cementitious-crumb rubber composite specimens when crumb rubber was acid treated, which is hypothesized to occur due to improvements in bond between the rubber inclusions and the cementitious matrix. Specimens containing core-shelled rubber showed improvement in damping over plain cement paste with a lower reduction in strength compared to crumb rubber mixtures, but improvements in damping were less than when acid treated crumb rubber was used. 2012 Elsevier Ltd. All rights reserved.