Abstract

The purpose of this study was to provide basic information on a method for the utilization of fly-ash and bottom-ash soil mixtures, including the physical and mechanical properties of the mixed soil, such as the unconfined compression test, the tensile strength test, and the freezing-thawing resistance in relation to the volume and curing time of the fly-ash and bottom-ash soil mixtures. Specimens with four different cement contents (4, 6, 8 and 10% of the total weight) and three different sizes (φ50 × 100 mm, φ100 × 200 mm and φ150 × 300 mm) were prepared to examine the characteristics related to specimen size and features, including the compression strength, microscopic structure, the freezing-thawing resistance and degree of wet-dry resistance. The results show that the larger-sized specimens and those with greater cement content had higher compressive strength, freezing-thawing resistance, and wet-dry resistance. Moreover, the reactive products for each specimen size were examined by microscopic structural analyses, such as SEM and EDS analyses, and it was observed that typical needle-structured ettringite was generated due to the blending of the cement.

Key words: Fly ash, bottom ash, soil mixtures, freezing and thawing, wet-dry.