Testing and Performance Criteria for Stabilized/Solidified Waste Forms - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 288

11.2.3.2 Flow-Around Tests

Flow-around tests are generally performed on monolithic samples. Leachant is
continuously or intermittently renewed, providing the driving force to maintain
leaching by diffusion. For these tests, the volume of leachant, and the leachant
volume to sample surface area ratio are prescribed. Typical tests include NEN 7345 25
and the CEN monolithic tank test. 26 These tests use an effective diffusion coefficient
determined from the results of the test to estimate contaminant release under sim-
plified disposal conditions.

11.2.3.3 Flow-Through Tests

Flow-through tests are performed on porous monoliths or granular material, with
the leachant continuously or intermittently flowing through the material, to measure
contaminant leaching under advective conditions. Typical tests include the ASTM
Column Extraction Method 27,28 and the European standard column test 29 being devel-
oped by CEN TC/292. These tests employ slow upward leachant flow to allow
saturation.

11.3 PRIMARY PHYSICAL TESTS

11.3.1 I NTRODUCTION

Most of the physical tests applied to untreated or treated S/S materials have been
adopted or adapted from test methods used for other materials such as concrete (BS
EN 12350, BS 1881, and BS 4550), soils for civil engineering purposes (BS 1337),
and stabilized materials for civil engineering purposes (BS 1924) and similarly from
ASTM standard test methods in volumes 04.01 (cement, lime, gypsum), 04.02
(concrete and aggregates), 4.08 (soil and rock), and 11.04 (environmental assess-
ment, hazardous substances and oil spill responses, waste management). Typical
applicability of the tests discussed below to either untreated or treated S/S material
is shown in Table 11.2. The most commonly used physical tests were found to be
three performance tests:

11.3.2 U NCONFINED C OMPRESSIVE S TRENGTH (UCS)

UCS (before and after immersion) is used as a measure of the ability of a monolithic
S/S material to resist mechanical stresses. 2,3 It relates to the progress of hydration
reactions in the product, and durability of a monolithic S/S material, and is therefore
a key variable. It is one of the most commonly used tests and there are numerous
standard methods for its determination, all of which involve vertical loading of a
monolithic specimen to failure. 30-38 Standard methods vary mainly with regard to
the specimen shape and size. Since these variables have an effect on the test result,
they must be clearly reported. Measurement of strength after immersion, as well as
before, is important to ensure that a specimen has set and hardened chemically rather
than merely dried, and to ensure that deleterious swelling reactions do not occur in