AASHTO T 357-15 pdf free download

AASHTO T 357-15 pdf free download.Predicting Chloride Penetration of Hydraulic Cement Concrete by the Rapid Migration Procedure.
8. SAMPLING, TEST SPECIMENS, AND TEST UNITS
8.1. The method requires cylindrical specimens with a diameter of 100 mm and a thickness of 50 mm, sliced from cast cylinders or drilled cores with a minimum original length of 100 mm. The cylinders or cores should meet the requirements described in R 39, T 23. or T 24M/T 24. Three specimens should be used in the test.
8.2. Obtaining Test Specimens:
8.2.1. If a drilled core is used, an outer (i.e., closest to the original surface) layer of the concrete (approximately 10 20 mm thick) should be cut ofT (Note 3), after which a 50 2 mm thick slice should be cut from the remaining core length to be used as the test specimen. The end surface of the test specimen that was closest to the original surface (i.e., the end surface that was adjacent to the discarded outer layer) should be exposed to the chloride solution (catholyte).
8.2.2. If a cast cylinder is used, an outer (i.e., closest to the troweled surface) layer of the concrete approximately 25 mm thick should be cut off (Note 3), after which a 50 ± 2 mm thick slice should be cut from the remaining length of the cylinder to be used as the test specimen. The end surface closest to the original troweled surface should be exposed to the chloride solution (catholytc).
8.2.3. The thickness should be measured to the nearest 0.1 nun with a slide caliper at four locations equally spaced around the specimen. All four thickness measurements shall be 50 ± 2 mm. Note 3—The term bcut here means to saw perpendicularly to the axis of a core or cylinder by means of a water-cooled diamond saw.
9. CONDITIONING
9.1. Brush and wash away any burrs from the surfaces of the specimen. Wipe excess water from the surfaces of the specimens.
9.2. (‘oat specimen sides with 5-mm epoxy or other suitable sealant if required. (See Note 2.)
9.3. Precondiiioning (Vacuian Saturation):
9.3.1. Place surface-dry specimens in the vacuum desiccator. Both end surfaces must be exposed.
9.3.2. Seal the desiccator and start the vacuum pump. The absolute pressure in the desiccator should decrease to a range of I to 5 kPa (7.5 to 37 mm Hg) within a few minutes. Maintain vacuum for 3 h.
9.3.3. With the vacuum pump still running, open the water stopcock and fill the desiccator with dc-aired tap water to cover the specimens. Close the water stopcock and maintain the vacuum for an additional I h.
9.3.4. Close the vacuum line stopcock and turn oil the vacuum pump. Reopen the vacuum line stopcock to allow air to reenter the desiccator. Maintain the specimens in this condition for 18 ± 2 h.
10. PROCEDURE
10.1. SeflipcWole4,):
10.1.1. Measure the temperature of the NaOlI and NaC1 solutions. If the temperatures are not within the range 23 ± 2°C, bring the temperatures of the NaOH and NaCI solutions to 23 ± 2°C before starting the test.
10.1.2. Place the plastic support (cathode) in the catholyic reservoir and fill the reservoir with about 12 L of NaCI solution.
10.1.3. For each of the three test specimens, place a rubber sleeve around the specimen as shown in
1:igure 2 (Note 4). Place clamps as shown in the figure and tighten snugly.AASHTO T 357-15 pdf download.