Microstructural Analysis of Paste and Interfacial Transition Zone in Cement Mortars Modified with Water-Soluble Polymers

Abstract:

The presence of water-soluble polymers affects the microstructure of polymermodified cement mortar. Such effects are studied by means of SEM investigation. Polyvinyl alcohol-acetate (PVAA), Methylcellulose (MC) and Hydroxyethylcellulose (HEC) are applied in a 1 % polymer-cement ratio. The polymers provide an improved dispersion of the cement particles in the mixing water. The tendency of certain water-soluble polymers to retard the flocculation of the cement particles minimizes the formation of a water-rich layer around the aggregate surfaces. They also provide a more uniform distribution of unhydrated cement particles in the matrix, without significant depletion near aggregate surfaces. Both effects enable to reduce the interfacial transition zone (ITZ). The polymers also provide a more cohesive microstructure, with a reduced amount of microcracks.

• Periodical: Key Engineering Materials (Volume 466)
• Pages: 21-28
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.466.21
• Online since: January 2011
• Authors: Elke Knapen, Dionys Van Gemert
• Keywords: Film Formation, Interfacial Transition Zone, Polymer Modification, Water-Soluble Polymer

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