Microstructural Analysis of Fly Ash-Based Stabilizer for Track Bed

This article is related to the unique application of fly ash-based stabilizer in the track bed of a railway line. In detail, it is focused on following analysis methods of samples structure and properties. The long-term observation of the stabilizer layer is based on the periodical sampling which is done once per year for the following compression strength test. Results collected over one decade showed the increasing tendency of the compression strength which is attributed to formatting the C-A-S-H gel. It is assumed it is done within structural conversion caused by the alkali activation of aluminosilicate components. This phenomenon was proved using electron microscopy. The statistical analysis of the compression strength resulted significant deviations the presence of which may be based on grains, poor stirring the mixture during placing, predisposed surfaces or micro cracks created during sampling in the railway track bed. The main outcomes of the paper are findings from non-destructive methods of Micro-CT and of electron microscopy, which were performed on specimens for the purpose of displaying their microstructure and identifying non-homogeneities of the specimens.