Carbonation tests on concrete are conducted to assess the depth of carbonation, which occurs when carbon dioxide from the environment reacts with calcium hydroxide in the concrete, potentially leading to corrosion of reinforcement. The test typically involves exposing a concrete sample to a carbonation environment, then spraying a pH indicator like phenolphthalein on the surface. A change in color indicates the extent of carbonation; the depth of the colorless zone reflects the carbonation depth. This test helps evaluate the durability of concrete, especially in reinforced structures, by estimating the likelihood of steel reinforcement corrosion due to carbonation-induced pH reduction, thereby informing maintenance and protective measures.