What is the purpose of carbonation test of concrete?

 Carbonation of concrete occurs when the carbon dioxide, in the atmosphere in the presence of moisture, reacts with hydrated cement minerals to produce carbonates, e.g. calcium carbonate.

this test to determine the percentage of carbonation in concrete

The carbonation test is a way to evaluate the concrete's strength reduction due to ageing.

i did not do this test before for concrete

i do it for steel as it is very important. in this case.