Alkali–aggregate reaction

Alkali-aggregate reaction is when two things, alkali (a type of chemical) and aggregate (small pieces of rocks or stones), don't get along very well. Alkali (like sodium or potassium) is often found in cement that is used to make things like buildings, roads, and bridges. When the cement is mixed with water, it hardens and becomes strong. However, if the rocks or stones used in the cement mix contain certain materials, like silica or reactive minerals, and the alkali reacts with these materials, it can cause the rocks to break down or expand. This can make the cement weaker and cause cracks and damage to form over time. It's like when two people don't get along and they argue or fight, it can cause problems and damage their relationship. In the same way, when alkali and certain types of rocks or stones don't get along, it can cause problems and damage the cement.