Admixtures

Alkali silica reaction (ASR) is the reaction between the alkali contained in cement and silica containing aggregate. There are two parts of this equation. ASR does not necessarily have to be of concern if one of the constituents is missing. Using potentially reactive aggregate in conjunction with low alkali cement or slag or flyash does not necessarily have to lead ASR damage.
Another variable is the type of the structure and location. For ASR to happen moisture is required. If the structure (for example a concrete retaining wall) has continuous access to moisture then ASR damage is going to be more detrimental and treatment of the structure might be very expensive.
If the structure is accessible and exposed only to rain for example, than ASR can be slowed down by reducing the moisture penetration into the structure. There are "breathable" coatings available on the market that allow diffusion of moisture out of the structure but do not allow moisture to enter the structure. Applying such a coating to a structure that shows signs of ASR can reduce the rate of ASR. There are also Lithium salts available in the market that are used to reduce the occurrence of ASR, These product are available as admixtures for new structures or as spray applied products to be used in existing structures.
None of these products are final solutions that eliminate ASR, but can be successfully used to manage the risk of severe damage from ASR.