Specification - Concrete Mix Design, Quality Control and Specification - page 116

Table 6.2 (Continued) Test methods for alkali-silica reactivity
Test name

Purpose Type of test Duration of test Comments

ASTM C 342, Potential
volume change of
cement-aggregate
combinations

To determine the
potential alkali-silica
reaction (ASR)
expansion of cement-
aggregate combinations

Mortar bars stored
in water at 23°C
(73.4°F)

52 weeks Primarily used for aggregates from

Oklahoma, Kansas, Nebraska, and Iowa.

ASTM C 441,
Effectiveness of
mineral admixtures
or GBFS in
preventing excessive
expansion of
concrete due to
alkali-silica reaction

To determine
effectiveness of
supplementary
cementing materials in
controlling expansion
from ASR

Mortar bars—using
Pyrex glass as
aggregate—stored
over water at
37.8°C (100°F) and
high relative
humidity

Varies: irst
measurement at
14 days, then 1, 2,
3, 4, 5, 9, and 12
months; every 6
months after that
as necessary

Highly reactive artiicial aggregate may
not represent real aggregate conditions.
Pyrex contains alkalies.

ASTM C 856,
Petrographic
examination of
hardened concrete

To outline petrographic
examination procedures
for hardened concrete;
useful in determining
condition or
performance

Visual (unmagniied)
and microscopic
examination of
prepared samples

Short duration,
includes
preparation of
samples and visual
and microscope
examination

Specimens can be examined with
stereomicroscopes, polarising
microscopes, metallographic
microscopes, and scanning electron
microscope.

ASTM C 856
(AASHTO T 299),
Annex uranyl acetate
treatment procedure

To identify products of
ASR in hardened
concrete

Staining of a freshly
exposed concrete
surface and viewing
under UV light

Immediate results Identiies small amounts of ASR gel

whether they cause expansion or not.
Opal, a natural aggregate, and
carbonated paste can glow—interpret
results. Accordingly tests must be
supplemented by petrographic
examination and physical tests for
determining concrete expansion.

Los Alamos staining
method (Powers
1999)

To identify products of
ASR in hardened
concrete.

Staining of a freshly
exposed concrete
surface with two
different reagents.

Immediate results