Determination of the carbonatation depth on concrete

The assessment of the state of conservation of concrete can be done on-site through the measurement of the carbonation depth, which can be detected through the chemical indicator of phenolphthalein, either in holes, or survey windows on the material surface. Carbonation is a current mechanism of concrete deterioration and it results from the reaction of calcium hydroxide with the carbon dioxide in the air, forming calcium carbonate and water. This process is accompanied by a reduction of the alkalinity of the concrete that, when it passes through the thickness of the concrete covering layer of reinforced concrete elements, and in the presence of water and oxygen, activates the corrosion process of the reinforcement, accelerating the degradation and reducing the durability of the reinforced concrete. Therefore, this test allows determining the depth and extent of concrete areas that need repair.



Printed in ncrep.pt