Existing test methods to characterize ASR potential of aggregates and mitigation ability of supplementary cementing materials such as the Accelerated Mortar Bar Test (AMBT) and the Concrete Prism Test (CPT) are widely accepted in the industry. Although, the AMBT is a rapid test, the results from this test can be unreliable, particularly with certain types of aggregates. The CPT is considered as a more reliable test; however, the duration of this test method renders it impractical for routine usage in the industry to screen deleterious materials or inefficient ASR mitigation measures. This book presents a new test method-Miniature Concrete Prism Test (MCPT) that overcomes the deficiencies of the AMBT and the CPT. This test method can also be employed to assess the mitigation effectiveness of supplementary cementing materials. Results from the MCPT of 12 reactive and non-reactive aggregates with known field performance were compared with the results from the AMBT and the CPT methods. Finally, an approach to evaluate ASR potential of job concrete mixture was proposed and two airfield taxiway-job mixtures with known field history were tested using the MCPT in this regard.