This paper presents the result of laboratory and field research on soil stabilization using fluid bed combustion fly ash. This type of ash is the result of the combustion of petroleum coke and limestone in an electric power generation plant (Petropower, located in the south of Chile), which makes it different from other types of ash used regularly in soil stabilization. The ash differs from the traditional ash used in soil stabilization, particularly because of (a) a high concentration of lime that may produce cementing compounds and (b) the presence of sulfates that may produce a secondary reaction such as the formation of gypsum and ettringite, resulting in a different level of expansion in some types of soils. The main objectives of the research were to characterize fluid bed combustion fly ash from the Petropower plant and to evaluate the technical feasibility of using this ash as a soil stabilizer. The laboratory and field research showed that this type of ash improves the mechanical properties and water susceptibility of most types of soils. Although laboratory experimentation proves that the secondary reaction produces soil expansion in clayey soils, field experimentation indicates that the secondary reaction that produces soil expansion may be controlled by an adequate laboratory design and an appropriate dose of fly ash.
Abstract