Testing and Performance Criteria for Stabilized/Solidified Waste Forms - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 302

Cement-stabilized materials for utilization in sub-bases and bases, under the
British specifications for the four categories CBM1-4, 130 are required to have min-
imum 7-day cube compressive strengths of 4.5, 7, 10, and 15 MPa, respectively. 131
In the Netherlands, the UCS requirement for stabilized material for use in sub-base
layers is 3 to 5 MPa. However, the American and South African specifications rank
strength as not being the primary requirement for cement-stabilized materials. 130
With respect to radioactive waste, the tests to demonstrate stability of cement-
solidified Class B and C wastes include an average UCS of 3.5 MPa (500 psi) using
ASTM C39/C39M. 127

11.5.4 H YDRAULIC C ONDUCTIVITY

The hydraulic conductivity limit is usually taken as 10 -9 m/s for in-ground treat-
ment (this value is usually used for clay liners and cut-off walls) 132 and utiliza-
tion. 15 USEPA tends to use 10 -9 m/s for disposal in a landfill. 133 A higher limit
value of 10 -8 m/s is suggested for disposal scenarios in the WTC protocol, on the
basis that secondary engineered barrier systems provide additional protection of
the environment. 15

11.5.5 O THER D URABILITY T ESTS

S/S materials subjected to both freeze/thaw and wet/dry durability testing at 28 days
are required to survive 12 cycles of the prescribed test procedures with a maximum
of 10% of the corrected cumulative dry mass loss. 15,44,48
For radioactive wastes, a technical position paper of the U.S. Nuclear Regulatory
Commission 127 summarized some testing and durability requirements for Class B
and C wastes:

1. The waste should be a solid form or in a container or structure that

provides stability after disposal.

2. The waste should not contain free-standing and corrosive liquids. That is,

the wastes should contain only trace amounts of drainable liquid, and, as
required by 10 CFR 61.56(b)(2), in no case may the volume of free liquid
exceed 1% of the waste volume when wastes are disposed of in containers
designed to provide stability, or 0.5% of the waste volume for solidified
wastes.

3. The waste or container should be resistant to degradation caused by

radiation effects.

4. The waste or container should be resistant to biodegradation.

5. The waste or container should remain stable under the compressive

strength inherent in the disposal environment.

6. The waste or container should remain stable if exposed to moisture or

water after disposal.

7. The as-generated waste should be compatible with the solidification

medium or container.