Fabricating and Testing Low-permeability Concrete for Transportation Structures

About the report:

Many concrete structures are not providing the expected service life. Repairs are costly, cause inconvenience to motorists, and raise safety concerns. The durability of concrete depends on, among other things, the ability to resist the penetration of harmful solutions, e.g., chlorides. Recently, pozzolanic materials have been widely used to decrease the permeability of concretes. In this study, the permeability of concretes containing portland cement alone or portland cement with a pozzolan (fly ash, silica fume) or a slag was determined by either the rapid permeability test (AASHTO T 277) or the ponding test (AASHTO T 259). Concretes were tested with either test to determine the reduction in permeability with time. Results show that both tests indicate the permeability of concretes. The rapid permeability test is more convenient and relatively faster than the ponding test. Permeability decreases with time, and the addition of pozzolans or slag is very effective in decreasing permeability.

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