Vittorio Longo

Thixotropic behaviour of cement pastes

Abstract In the present work the thixotropic behaviour of fresh Portland cement pastes is examined on the basis of the stress transients determined at constant shear rate. Some significant quantities are considered: the difference between maximum and equilibrium shear stresses, the breakdown area and the density of the energy absorbed by thē material for the breakdown of the thixotropic structure. A distance parameter is proposed in order to evaluate the influence of the specific surface and water/cement ratio on these quantities.

A Thixotropic Model for Cement Pastes

Several researches1,9 have indicated the thixotropic behaviour of cement pastes. When subjected to shear, cement pastes undergo a structural breakdown process. Pastes can be defined as partially thixotropic systems since, even if a long rest period follows the shear action, they have no appreciable tendency to build up their structure.