Assessing condition of concrete affected by internal swelling reactions (ISR) through the Damage Rating Index (DRI)

The Damage Rating Index (DRI) has been increasingly used in North America since it answers interesting questions on the cause and extent of damage in concrete. Currently, the DRI is mostly used to appraise alkali-silica reaction (ASR) affected concrete and there is very few research on the evaluation of other distress mechanisms through this method. This work presents the use of the DRI to assess condition of concrete affected by internal swelling reaction (ISR) mechanisms (i.e. ASR, delayed ettringite formation and freeze-thaw cycles), with the aim of verifying the suitability of the method to become a comprehensive damage evaluation protocol. Results show that the DRI number, represented by plots or bar charts, enables a quantitative damage evaluation of concrete regardless of the distress mechanism type and degree. Moreover, the implementation of an extended DRI version makes the method more suitable to describe progress of different ISR deterioration processes in concrete.