<p>Carbonation rate and cumulative seismic damage directly affect the mechanical behavior of concrete structures. Statistical analysis of multiple sets of carbonation depth data for reinforced concrete components in the existing literature shows that the carbonation rate of components with a service life exceeding 50&#xa0;years gradually decreases. The existing formulas for estimating the carbonation depth produce significant errors when calculating the carbonation coefficient of concrete with a service life exceeding 50&#xa0;years. Using the least squares method in conjunction with data regression and grey modeling, this paper proposes a method for estimating the carbonation depth and carbonation coefficient of long-aged concrete based on the service life, which can be used to calculate the carbonation rate of components in concrete structures. Damage analysis is then performed on building structures using mainshock and aftershock seismic waves. In addition, based on a case study of a concrete-frame structure, the relationship between the number of aftershocks and structural response is determined by analyzing the peak inter-story drift angle and maximum top displacement of the frame structure for different mainshock and aftershock conditions. Finally, vulnerability analysis of the structure subjected to mainshock and aftershocks is performed to determine the quantitative relationship between the peak inter-story drift angle and carbonation, as well as the cumulative damage from aftershocks. The results indicate that under the action of mainshock and aftershocks, the damage to non-carbonated structures is minimal to moderate; for structures with a 50-year service life, the damage is primarily moderate; for structures with a 100-year service life, the damage is moderate to severe compared with non-carbonated structures. This reflects the structural stiffness degradation caused by carbonation, resulting in more severe cumulative seismic damage.</p>