The measurement of the carbonization depth of concrete is a key means to evaluate the durability of concrete structures. The following is the detailed measurement process:
First, prepare the necessary tools, including a drill or chisel, a 1% phenolphthalein alcohol solution, and a steel ruler.
Next, a hole with a diameter of about 15 mm is made on the surface of the predetermined measurement area, and the depth should be comparable to the thickness of the protective layer. In this process, it must be ensured that the concrete at the edge of the hole is not damaged.
Then, clean the holes of powder and debris. It is important to note that liquids should not be used for rinsing to avoid affecting the measurement results.
After that, spray an appropriate amount of phenolphthalein test solution with a concentration of 1% into the well to ensure that the test solution is evenly moist on the surface but does not run.
The interaction between phenolphthalein test solution and concrete was observed. Due to the alkaline nature of the concrete, the phenolphthalein test solution will undergo discoloration. Pay special attention to the boundaries between carbonized and non-carbonized concrete, the non-carbonized parts will often appear pink.
Next, a steel ruler is used to accurately measure the vertical distance from the carbonized and uncarbonized interface to the concrete surface, which is the carbonization depth. It is recommended to take no less than 3 measurements and take their average values for more accurate results, with measurements accurate to 05mm。
In addition, when the depth of carbonization is used to assess the degree of damage, it should be classified according to the damage condition of the surface and a representative site should be selected for measurement.
In summary, by following the above steps, we are able to measure the carbonization depth of concrete with relative accuracy. However, it is important to note that the effect of carbonization on plain concrete and reinforced concrete is different. For plain concrete, carbonization may improve its durability; For reinforced concrete, carbonization will reduce the alkalinity of the concrete and weaken the protective effect on the reinforcement, which may lead to rusting of the reinforcement and affect the durability and safety of the structure. Therefore, it is essential to regularly check the carbonization depth of concrete structures to maintain the safety and longevity of the building.