Modeling the Heat of Hydration of Concrete Incorporating Fly Ash

The hydration evolution of concrete with different water-binder ratios and fly ash replacement percentages are studied by experimental investigation. Based on equivalent age concept, the effect of water-binder ratio as well as fly ash dosage on the ultimate temperature rise and heat release coefficient are analyzed with the hyperbolic-type calculating model of adiabatic temperature rise adopted. It is indicated that the adiabatic temperature rise will be reduced with the increase of water-binder ratio and the incorporation of fly ash. The hydration evolution process will be accelerated with the decrease of water-binder ratio, but slowed down when the amount of fly ash is enhanced.

Assessment of the Airborne Release Coefficient During Cutting Operations in the Frame Dismantling Studies

In the frame of the decommissioning of nuclear facilities, many cutting techniques have been studied in different configurations, in order to qualify the performance of the tools implemented and also the quantity and characteristics of the wastes and secondary emissions produced. The present paper, calling the operational conditions of each tool, presents a synthesis of the results obtained from the suspension or airborne release point of view. The knowledge of the suspension fraction of radioactive aerosol contamination is needed for the safety analysis of nuclear installation and for the radioprotection of workers as well. This synthesis shows that the suspension fraction can vary over several orders of magnitude according to the configurations studied and provides relevant information for the dismantlers.