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Innovative process routes for a high-quality concrete recycling
Waste Management (New York, N.Y.)
|March 16, 2013
Summary
This study explores electric pulses and microwave heating for concrete waste processing. Electric pulses are more energy-efficient for aggregate liberation but require water, posing a recycling challenge.
Area of Science:
- Materials Science
- Civil Engineering
- Waste Management
Background:
- Concrete waste presents a significant environmental challenge due to disposal and resource depletion.
- Current concrete recycling methods often struggle with efficient aggregate separation from cement paste.
- Developing advanced processing techniques is crucial for sustainable construction and circular economy principles.
Purpose of the Study:
- To investigate alternative methods for processing concrete waste, focusing on weakening the mortar matrix.
- To evaluate the effectiveness of electric pulses and microwave heating in enhancing selective aggregate liberation.
- To compare the efficiency, robustness, and energy consumption of these two novel techniques.
Main Methods:
- Concrete waste samples, both lab-made and from a demolition site, were subjected to electric pulse treatment and microwave heating.
- Mechanical stresses were induced to embrittle the mortar matrix, facilitating selective crushing.
- The liberation of cement paste-free aggregates was assessed after treatment and subsequent crushing/grinding.
Main Results:
- Both electric pulses and microwave heating successfully weakened concrete samples and improved aggregate liberation.
- Electric pulse treatment demonstrated higher efficiency and robustness compared to microwave heating.
- Electric pulses consumed significantly less energy (1-3 kWh/t) than microwaves (10-40 kWh/t).
Conclusions:
- Electric pulse and microwave heating are viable alternative methods for concrete waste processing.
- Electric pulse treatment is more energy-efficient and robust but its application is limited to wet conditions.
- Further research is needed to overcome the limitations of electric pulse treatment for practical aggregate and cement paste recycling in cement production.
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