Rationalizing the impact of aging on fiber-matrix interface and stability of cement-based composites submitted to carbonation at early ages

Abstract

The objective of this work is to show the effect of carbonation at early stages on fiber–cement composites and impact on hydration, chemical and dimension stability. Carbonation increased the content of CaCO3 polymorphs and consumed Ca(OH)2 and other hydrated calcium phases. Micrographs and energy-dispersive spectrometry showed the CaCO3 formed is precipitated in the pore structure of the matrix, decreasing diffusion of Si, S, and Al during hydration. Therefore, a refining process of pore sizes is produced, and fiber–matrix interface in carbonated composites was improved, leading to volume stabilization of the composite, as indicated by lower drying shrinkage and lower porosity.