Evolution in Modeling Microstructure Formation in Polymer-Cement Concrete

Hardened PCC material consists of two interpenetrating matrices of polymer phase and hydrated cement with random dispersion of the aggregates. Different models have been proposed to describe the built up of microstructure in this material, and to explain or even to design its characteristic properties. This paper deals with the evolution of the microstructure models with time, showing a growing understanding of the microstructure formation during hydration and hardening, as well as a better knowledge of the morphology and behavior of the polymer phase within the composite material. Better understanding of microstructure formation was supported by the development and improvement of SEM analysis technique, and further integration of the time scale in the models was enabled by ESEM analysis during hydration and hardening of fresh mixes. Enhancement of SEM resolution and magnification capabilities also enabled to study the effect of very low amounts of polymer on the microstructure. The paper deals with the physical mechanisms, described by the models, and shows the improvements added in the successive models, leading to an increased understanding of the synergies realized by the interaction and collaboration of polymers and hydraulic cement.