Cementing Radioactive Waste

Cement would make a useful material for locking away radioactive waste except for the fact that conventional cement is susceptible to weathering. When water infiltrates its pores, it freezes and when it thaws, the resulting cracks can fracture the cement blocks. Moreover, adding foreign materials to the standard cement slows the hydration process required for the mix to harden leading to greater porosity and an increased risk of radioactive elements leaching out through long-term wear and tear.

Read more here...

Credit: http://www.iucr.org