Published online by Cambridge University Press: 22 February 2011
Materials of very high flexural strengths (> IOOMPa) can be made by high shear mixing of cement pastes with small amounts of water soluble polymer. Two such systems - high alumina cement/partially hydrolysed polyvinyl acetate and OPC/polyacrylamide - have been examined using a variety of techniques including isothermal calorimetry, infra-red spectroscopy and X-ray diffraction. In both systems the polymer addition appears to become cross-linked by ions released by the cement powder leading to an increase in stiffness of the material. In particular the reactions involved in the OPC system are analogous to those occurring in certain dental cements. The importance of removing excess water from the pastes is demonstrated.