This test method is used to determine the flexural strength of specimens prepared and cured in accordance with Test Methods C42/C42M or Practices C31/C31M or C192/C192M. Results are calculated and reported as the modulus of rupture. For the same specimen size, the strength determined will vary if there are differences in specimen preparation, curing procedure, moisture condition at time of testing, and whether the beam was molded or sawed to size. The measured modulus of rupture generally increases as the specimen size decreases. The results of this test method may be used to determine compliance with specifications or as a basis for mixture proportioning, evaluating uniformity of mixing, and checking placement operations by using sawed beams. It is used primarily in testing concrete for the construction of slabs and pavements. For identical test specimens, the modulus of rupture obtained by this test method will, on average, be lower than that obtained by Test Methods C293/C293M.
KeywordsC78 - Flexural Strength of Concrete
ICS CODE91.100.30 (Concrete and concrete products)
ASTM C78 / C78M-18, Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading), ASTM International, West Conshohocken, PA, 2018, www.astm.org