This publication provides introductory technical guidance for civil engineers, structural engineers and other professional engineers and construction managers interested in alkali/silicate aggregate reactions in concrete. Here is what is discussed: 1. ALKALI-SILICA AGGREGATE REACTIONS, 2. CRITERIA FOR RECOGNITION OF POTENTIALLY DELETERIOUS CONSTITUENTS IN AGGREGATE, 3. METHODS OF DETERMINING THE POTENTIAL FOR REACTIVITY, 4. RELIABILITY OF AVAILABLE TEST METHODS, 5. CRITERIA FOR EVALUATING POTENTIAL REACTIVITY, 6. CONTROL OF ALKALI-SILICA AGGREGATE REACTIONS.