ASTM standards define precise procedures for performing field tests to determine the quality of freshly mixed concrete. Usual field tests measure consistency, strength, unit weight, air content, and temperature. Many test details seem trivial, even arbitrary. However, ASTM standards establish uniformity in the testing methods. By always performing tests the same way, it's possible to detect changes in fresh concrete that could affect concrete performance. Understanding the scope, significance, and procedure of each test for fresh concrete is the first sep to achieving accurate results.
Follow procedures given in ASTM C 172 to ensure the sample is truly representative of the freshly mixed concrete being tested. The slump test (ASTM C 143) measures concrete consistency, or the ability of fresh concrete to flow. ASTM C 31 covers making, curing, protecting, and transporting concrete test specimens under field conditions. Procedures for compression-strength testing of these cylinders are described in ASTM C 39. Aggregate amount and relative density, air content, and water and cement contents determine the unit weight of fresh concrete, which is measured according to ASTM C 138.