Engineering behavior of soft clays treated with circulating fluidized bed combustion fly ash.

摘要

This thesis presents results from a comprehensive laboratory study carried out to investigate the feasibility of using Circulating Fluidized Bed Combustion fly ash for improvement of engineering properties, particularly strength and stiffness, of soft clays. The CFBC fly ash was obtained from the AES power plant in Guayama, P.R. A soft clay from Hormigueros, P.R. was treated with different admixture percentages of this fly ash. Improvement levels were evaluated based on unconfined compression test carried out at different curing times. Other soil characteristics like plasticity, compaction properties, and expansion were monitored. A comparative analysis was also presented using class C fly ash and Hydrated lime. In general, results indicate that the soil treated with CFBC fly ash showed improvement. However class C fly ash produced a superior effect in the levels of improvement when compared with CFBC fly ash and hydrated lime. Soil samples treated with CFBC fly ash were found to develop crystal formation at 35 days of curing. Recommendations for future works are presented.