MSW fly ash stabilized with coal ash for geotechnical application

Area of Science:

• Environmental Engineering
• Geotechnical Engineering
• Materials Science

Background:

• Municipal solid waste (MSW) fly ash poses geo-environmental risks due to toxic heavy metals.
• Ensuring engineering safety, including strength and durability, is crucial for fly ash utilization.
• Soluble salts in MSW fly ash significantly influence stabilization performance.

Purpose of the Study:

• To evaluate the solidification and stabilization of MSW fly ash.
• To minimize geo-environmental impact and ensure engineering safety.
• To investigate the effectiveness of cement and fluidized bed combustion coal fly ash (FCA) as stabilizers.

Main Methods:

• Experimental evaluation of MSW fly ash mixtures stabilized with cement and FCA.
• Unconfined compressive strength tests.
• Leachate and soaking tests to assess durability and heavy metal containment.

Main Results:

• Cement stabilization alone offers limited strength and durability but aids heavy metal containment via alkalinity.
• Fluidized bed combustion coal fly ash (FCA) enhances strength and durability but shows early-stage cadmium (Cd) leachate.
• A combination of cement and FCA achieves high strength, durability, and effective heavy metal containment.

Conclusions:

• Combined cement and FCA stabilization is a viable method for MSW fly ash.
• This approach ensures high strength, soaking durability, and heavy metal containment.
• Stabilized MSW fly ash with cement and FCA is suitable for practical application in embankments.