ABSTRACT
ACI 214R provides a means to judge the testing variability and is summarized below:
1. Variability due to testing is estimated by the within-batch coefficient of variation (V1) calculated based on the average range (R) in strengths of companion (replicate) cylinders, comprising a strength test result, which are cast from the same composite sample of concrete tested at the same age using Equation 10.1. Since the cylinders are made from the same concrete sample, the material and manufacturing variability are assumed to be negligible, and the strength difference between the cylinders is assumed to be due to testing variability. Average range should be calculated from at least 10 strength test results. In Equation 10.2, the within-batch coefficient of variation (V1), in percent, is determined from S1 and the average strength (X).
