Low-carbon concrete was developed by replacing traditional cement with low-carbon cementitious materials and coarse aggregates with coal gangue. A systematic investigation was conducted on the evolution of mechanical properties and failure modes of concrete at various hydration ages. The impact resistance, including the number of impacts, failure morphology, and impact energy, was analyzed through a series of impact tests. Microscopic testing techniques were employed to reveal the morphological features of hydration products and the structural characteristics of the interfacial transition zone (ITZ). Nuclear magnetic resonance (NMR) technology was utilized to quantitatively characterize the evolution of porosity and pore size distribution. Based on the Weibull distribution model, an impact life prediction formula was established, offering theoretical support for the durability design of low-carbon concrete under dynamic loading conditions.