Standard Test Method for Air-Permeability Coefficient of Hardened Concrete by the Double-Chamber Vacuum Cell Method

Importancia y uso:

4.1 This test method covers the determination of the air-permeability coefficient, kT, of hardened concrete, and is applicable to laboratory testing of specimens or to in-place testing of concrete elements.

4.2 The air-permeability coefficient, kT, is closely related to the structure (volume, size, tortuosity, connectivity) of the empty pores in the near-surface concrete (1).

4.3 The air-permeability coefficient, kT, has shown good correlation with the results of other penetrability tests such as Test Methods C1202, C1556, and C1585, AASHTO T 259, EN 12390-8 and EN 12390-18 (1) and (2).

4.4 The near-surface layer (typically 10 to 80 mm deep) investigated by this test method is sensitive to mixture composition and concrete practices such as placement, consolidation, finishing, and curing. Hence, the in-place application of the test method evaluates not just the characteristics of the concrete as produced, but the quality of the end-product, involving the contribution of all involved in the concrete construction process.

4.5 The test method is suitable to evaluate the efficiency of curing methods and of special treatments such as controlled permeable formwork liners or sealers (1). However, the effect of sealers that allow the concrete to “breathe” should not be assessed by this method.

4.6 The method is intended to establish the quality of relatively new structures, although it has been used as a tool for condition assessment of structures after long periods of service. Care should be taken in the latter case, as the lengthy exposure of these structures to the environment may generate carbonation, surface deteriorations, cracks, delamination, and spalling, making the interpretation of the test results more difficult.

4.7 In contrast to electrical conductivity tests such as Test Method C1202, Test Method C1876 and AASHTO T 358, the result of this test is not influenced by the electrical conductivity of the pore solution. Hence, it is applicable to concretes containing conductive components, such as some corrosion inhibitors, steel fibers, and steel bars.

4.8 The method is applicable to concretes with air-permeability coefficients within the range 0.001×10^-16 m² to 100×10^-16 m² (see Note 2). The test method is not suitable to test concretes intentionally made with high porosity, such as cellular or pervious concrete, or to concrete with cracks within the zone affected by the test.

Note 2: Table X3.1 provides a recommended classification of concrete permeability based on the kT values.

Subcomité:

C09.64

Volúmen:

04.02

Palabras clave:

air-permeability; double-chamber vacuum cell method; hardened concrete; in-place test; laboratory test; moisture compensation; nondestructive;