Damping and Microstructure of Graphene/Carbon Nanotube-Modified Cement Composites

The development of lightweight, high-damping building materials is critical for enhancing the seismic resilience of civil infrastructure. This study introduces a novel approach to synergistically improve the damping and mechanical properties of cementitious composites by incorporating one-dimensional carbon nanotubes (CNTs) or two-dimensional graphene nanoplatelets (GNPs). The novelty lies in (1) a direct comparison of 1D versus 2D carbon nanomaterials efficacy within a vibration-relevant frequency range (0.5–2 Hz); (2) the use of the Ca(OH)2 orientation index, derived from X-ray diffraction (XRD), to link microstructural texturing with macroscopic dynamic performance; and (3) establishing clear mechanistic link between carbon nanomaterials dispersion, pore structure evolution, and the resultant balance between stiffness and damping. Dynamic mechanical analysis identified an optimal dosage of 0.1% by weight for both nanomaterials. Comprehensive microstructural characterization (SEM, MIP, XRD, TGA/DTG) revealed that the carbon nanomaterials act as nucleation sites, promoting cement hydration and refining the pore structure. This structural enhancement concurrently improved mechanical strength and energy dissipation capacity. The primary damping mechanism was identified as interfacial friction and slippage at the nanofiller–matrix interface. These findings provide fundamental insights for the rational design of high-performance cementitious composites and offer an evidence-based pathway for creating advanced seismic-resistant materials.