Concrete is a durable material. The durability of concrete is defined by the ability of concrete to resist weathering action, and chemical attack while maintaining it’s desired, engineering properties. However, due to the use of inappropriate materials, poor construction practicing, insufficient curing, and improper mix designs, many structures show premature and serious deterioration. Premature deterioration is a global problem that costs billions of dollars annually.
To have a durable structure many factors should be combined, including a proper mix deign. But what is the best way to quantify the durability of a mix? Nobody doubts that for having a durable structure, permeation of water into the concrete should be reduced. How should permeation be measured?
Overall, tests such as water absorption, surface absorption, water permeability, or chloride permeability are commonly specified. Which test is more relevant?
Water absorption (such as BS1881 part 122) is an absorption test that measure water absorption by an immersed of the sample . These tests are more relevant for an application in which concrete is exposed to low or no hydrostatic pressure.
Permeability test (BS12390/DIN1048): This is the true permeability that evaluates the resistance of concrete against the penetration of water under hydrostatic pressure. This test should be considered as a predominate test to evaluate the case in which concrete is subject to hydrostatic pressure.
Chloride permeability test (ASTM 1202- RCP): It is the standard test method for Electrical Indication of concrete’s ability to resist Chloride Ion penetration. As per ASTM, this test method is suitable for the evaluation of materials and material proportions for design purposes, and research and development. However, it has incorrectly become one of the tests that is used to evaluate the durability of concrete.
In addition to the permeability, the tendency of concrete to cracking plays a big role in order to have a durable mix, but this property is usually ignored.
Overall, concrete can be exposed to many different environments, so a variety of different test methods are needed to evaluate the durability of concrete.