The multiscale nature of this long-term phenomenon makes the assessment of concrete structures impacted by alkali-silica reaction (ASR) a challenging problem. The formation of an expansive alkali-silica gel at reaction product level signals the beginning of the reaction within the components of the concrete. Given that the expansive gel is constrained within the concrete micro-structure, an internal pressure builds up and causes damage to the aggregate.The experimental analysis, which combines laboratory testing with literature data, reveals a statistically significant correlation between concrete expansion and the deterioration of the mechanical properties of concrete specimens damaged by ASR maintained under free-expansion circumstances. The strongest indicator of ASR signals in concrete, as opposed to compressive strength, is the elastic modulus, which exhibits the quickest rate of degradation and lowest residual value.A significant difference is seen when comparing the behaviour of unaffected and damaged concretes in terms of strength-stiffness correlations. The suggested multiscale material modelling technique yields a method for material characterization that can be expanded to the structural level as well as the reaction products.