Published online by Cambridge University Press: 22 February 2011
A model has been developed for the flexural strength of Portland cement pastes, based upon observed fracture behaviour of both normal and high strength pastes. Fibrillar or foil-like elements pull apart at a yield stress which is characteristic of the number of elements and interfacial shear strength. The former can be maximised by using a low water/cement ratio and the latter by inclusion of water-soluble polymer, followed by suitable drying. It is proposed that this is the mechanism by which high strength may be attained in Portland cement.