Tailoring damping efficiency in cementitious composites: A coating approach integrating carbon nanotube networks and viscoelastic polymer interfaces

This study investigates the damping performance of cementitious composite mortars modified with composite-coated aggregates, focusing on the role of carbon nanotube (CNT) concentration in polymer coatings and its effects on interfacial and damping properties. The primary focus is on understanding the role of CNT concentration within polymer coatings, as well as its impact on interfacial and damping capacity. By systematically varying CNT content from 5 wt% to 20 wt%, we demonstrate that increased CNT concentrations markedly enhance interfacial bonding strength and damping efficiency. Backscattered electron (BSE) imaging reveals a cohesive bond between the composite coating and matrix, with the porosity of the interfacial transition zone (ITZ) reduced by 82.1 % compared to unmodified controls. This reduction is linked to the adsorption of calcium ions by ester groups in polyacrylate ester (PAE), which refines the ITZ pore structure. Furthermore, the elastic modulus of the composite coating exhibits a linear correlation with CNT concentration, confirming improved mechanical performance at higher loadings. By optimizing CNT content, this work achieves a synergistic balance between mechanical strength and damping capacity, proposing a novel design framework for high-performance composite mortars in structural engineering applications.