Influence of curing temperature dependent microstructure on early-age concrete strength development

An experimental campaign for the compressive strength history of concrete specimens cured at different quasi-isothermal conditions ranging from 15 to 70 degrees Celsius is presented. Furthermore, hydration kinetics of the Portland cement employed in the concrete mix design was characterized by isothermal heat-flow calorimetry, giving access to the degree of hydration history for the various curing temperature histories. Interpreting the degree of hydration vs. strength data with a power-law based material function, the backcalculated power-law exponent is set into context with common material functions for the compressive strength of open-cell foams with different microstructures. A simple multiscale engineering model for upscaling of compressive strength is outlined, allowing the assessment of the proposed analogy with open-cell foams.