Proton spin-lattice relaxation study of the hydration of self-stressed expansive cement

Proton spin-lattice relaxation, compressive strength, and water tightness m easurements have been undertaken in order to study the hydration process an d the mechanical properties of Portland cement modified with a calcium sulf oaluminate-based expansive additive (EXPAD). The compression strength of th e modified cement was more than 70% higher while water permeability was abo ut 60% smaller than in the unmodified cement. Magnetization-recovery curves analysis allowed for a time-resolved monitoring of both the increase of th e internal surface as well as the formation of solid products during the hy dration. A significant difference between the hydration kinetics of modifie d and unmodified cement was observed. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.