Thermal diffusivity measurements in curing portland cement

The temperature distribution within a cylindrical sample of Portland cement when a short pulse of energy is supplied is derived in absence of heat losses or heat generation. The model readily allows determining the thermal diffusivity of Portland cements from experimental measures of temperature. Two other models are generated separately to study these effects. These last two models explain the experimental data found for curing Portland cement pastes. Thermal diffusivity measurements are based on the implications of the ideal model, but have been found highly affected by heat losses and heat generation. Heat generation affects these measurements more importantly than heat losses; the amounts of heat generated or lost are small compared to that supplied by the pulse (0.01 to 0.1 %), but are enough to significantly alter the values of thermal diffusivity. An analysis of the utility of these models reveals that thermal diffusivity must be calculated between 2 and 4 minutes after the pulse to minimize errors.