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  4. Low-alkaline cement created with rice chaff

Low-alkaline cement created with rice chaff

 

Published by
 World Cement,

Osaka University and a Hokkaido cement company have co-developed a low-alkaline cement using rice chaff that will strengthen the durability of final nuclear waste disposal sites.

The development of low-alkaline cement is essential for the construction of nuclear disposal facilities must stay durable for up to 100 000 years to prevent radioactive materials from escaping.

In nuclear repositories, waste will be solidified with glass and placed in metallic containers before being covered with clay and buried deep underground.

If normal cement is used underground, it will react with groundwater, producing calcium hydroxide and causing groundwater to become highly alkaline. This causes cracking and deterioration in the nearby clay and bedrock.

To lower the alkaline levels in cement, Katsuyoshi Kondo, a professor at Osaka University’s Joining and Welding Research Institute, mixed silica dioxide extracted from rice chaff with cement. Silica reacts with calcium hydroxide and weakens alkaline.


Edited from source by Joseph Green. Source: Japan Times

 

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