Behaviour of cement-treated MSWI bottom ash

Area of Science:

• Geotechnical Engineering
• Materials Science
• Environmental Engineering

Background:

• Bottom ash from municipal solid waste incineration (MSWI) is increasingly used in road construction.
• French legislation restricts landfilling of reusable waste and sets environmental criteria for bottom ash utilization.
• Chemical instability in bottom ash, particularly aluminum oxidation, can lead to expansion, cracking, and road failure.

Purpose of the Study:

• To evaluate the swelling potential of cement-treated MSWI bottom ash.
• To understand the role of aluminum oxidation in the swelling reaction.
• To assess the effectiveness of different binders and treatments in mitigating swelling.

Main Methods:

• Investigated cement-treated MSWI bottom ash over four years.
• Conducted various tests to analyze swelling reactions.
• Examined the influence of different binders with varying clinker content.
• Studied the kinetics of the aluminum-binder reaction.
• Developed a specialized cell for measuring swelling pressure.

Main Results:

• Highlighted the critical role of aluminum oxidation in the swelling process of bottom ash.
• Demonstrated the effectiveness of certain treatments and binders in controlling expansion.
• Provided insights into the reaction kinetics between aluminum and binders.
• Introduced a novel method for quantifying swelling pressure.

Conclusions:

• Accurate estimation of MSWI bottom ash swelling potential is crucial before road construction.
• Understanding aluminum-binder reactions is key to preventing expansion-induced road damage.
• The developed swelling pressure measurement cell offers a valuable tool for material assessment.