摘要: |
As the coal remains the world's most abundant and accessible fossil fuel, the production of energy from coal will inevitably generate waste materials, i.e., the coal combustion products (CCPs). From 2002 to 2009, about 40% of CCPs was reused, while only 2.8% of the CCPs were used in pavement. This study intends to study the high volume reuse of fly ash, a major component of CCPs, in geotechnical engineering with organic additives, such as surfactant and polysaccharides. The microscopic properties, the unsaturated behaviors, and the unconfined compressive strength of fly ash and fly ash-soil mixture are studied. The microscopic imaging technique will provide the size, shape, and structure of the mixture. Then the water content and matric suction relationship, or soil water characteristic curve (SWCC) were measured. The suction can be calculated by the size and shape information from microscopic study by Laplace equation, and SWCC can also be predicted from particle size distribution. On the other hand, SWCC can also be used to predict the strength of fly ash-soil mixture. Furthermore, the physicochemical properties of the influent and effluent will be monitored to detect any chemical reactions. The outcome will provide the guideline on organic type and quantity, optimum fly ash to soil ratio, and water content of mixture for optimum performance in terms of strength. By connecting the intrinsic relations between microscopic behavior and the macroscopic mechanical properties, the understanding of the mechanisms for strength variation are advanced. |