Verification, Validation, and Variability of Virtual Standards

As the potential of computer modeling of hydration and microstructure development of cement-based materials approaches realization, the development of virtual standard test methods becomes a viable possibility. In creating these virtual standards, just as with the development of any physical standard test method, verification, validation (calibration), and variability must all be considered. These three issues will be discussed in reference to the ongoing development of a prototype virtual test method for the heat of hydration of ordinary portland cement within ASTM subcommittee C 01.26. The virtual test method employs the CEMHYD3D v3.0 cement hydration and microstructure development model and an early-age physical measurement of chemical shrinkage (via the ASTM C 1608 test method), to predict the 7-day and 28-day heat of hydration values in comparison to those measured via the ASTM C 186 Heat of Hydration test method in recent Cement and Concrete Reference Laboratory cement proficiency sample programs.