This investigation into various aspects of alkali silica reactivity (ASR) as it affects performance of highway structures, emphasized the practical needs of the concrete engineer with respect to the evaluation of the potential of aggregate for expansive ASR in new concrete, procedures to evaluate material for safe use in new concrete, and means to mitigate ASR and associated adverse effects in existing concrete. A rapid test method, based on immersion of mortar bars in sodium hydroxide solution, originated by the National Building Research Institute of South Africa was evaluated and extended to identify cement alkali levels and pozzolan proportions required to prevent deleterious ASR with particular aggregate. The efficacy of using lithium salts in concrete to suppress expansion due to ASR was researched. Reaction chemistry and dosages were studied. Results were favorable and the approach is highly recommended. Means to mitigate ASR were also studied. Restraint to expansion and application of lithium hydroxide solutions are possible means to control expansion due to ASR.