Development of pore structure, moisture sorption and transport properties in fly ash blended cement-based materials

Abstract

This study documents how the pore structure develops with time in cement-based materials with varying fly ash replacement. Heat production was measured during the first days, water vapour desorption isotherms were determined at different times up to 18 months, and moisture transport properties were measured after one year. Long-term fly ash reactions alter the pore structure considerably. The fly ash does not fill pore volume but refines porosity. After one year, fly ash replacement resulted in a factor 2–5 lower moisture diffusion coefficients. Aggregates have little effect on the measured pore structure; sorption isotherms for mortar and concrete can be determined on cement paste.

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