Extracting kinetic parameters from penetration resistance measurements

ASTM C403 penetration-resistance data are typically fitted with exponential or power functions. Given that the forms of these functions are suggested by either first-order or general-order reaction kinetics, this paper explores applications of kinetics-based interpretations of penetration-resistance data. Data effectively fitted with the exponential function display a pattern associated with the output of a first-order reaction, while data effectively fitted with a power function display a pattern associated with the output of a general-order reaction. Curve-fitting parameters contain “apparent” rate constants, useful for obtaining activation energy for setting behavior. The difference between development of mechanical properties such as penetration resistance with time, and the complex chemistry of multi-phase hydration reactions in the first hours after batching is discussed.