Results of an Interlaboratory Test Program: Compressive Strength of Concrete

Abstract

Abstract Although both ASTM and CSA have had standards for testing the compressive strength of concrete cylinders since the 1920s, neither standard contains a statement of the within- and between-laboratory precision of its test method as prescribed by Practice for use of the Terms Precision and Bias in ASTM Test Methods (ASTM E 177). This paper describes an interlaboratory study performed by 16 CSA-certified Ontario testing laboratories in accordance with Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method (ASTM E 691). The analysis shows that the variability of the test results increases with the mean strength of the concrete. A precision statement based on the results reported here is recommended for inclusion in Test Method for Compressive Strength of Cylindrical Concrete Specimens (ASTM C 39) and CSA A23.2-9C (Compressive Strength of Cylindrical Concrete Specimens).