chapter 3 rigid pavement - DOT On-Line Publications - Department ...

FHWA TECHNICAL ADVISORY T 5080.17
July 14, 1994
(a) A vinsol resin type admixture should be
added when fly ash having a variable
loss on ignition (LOI) content (between
3 percent and 6 percent) is present.
This is because of the effect that fly
ash's fineness and carbon content has on
the air entrainment system. Fly ashes
not having a variable LO1 do not have an
adverse impact on entraining agents and
therefore vinsol resin type admixtures
may not be necessary.
(b) The specifications for air entraining
admixtures are contained in
AASHTO M 154.
(2) Chemical admixtures include water reducers,
retarders, accelerators, high range water
reducers (superplasticizers), corrosion
inhibitors and combinations of the above.
The specifications for chemical admixtures
are contained in AASHTO M 194.
(a)
(b)
(c)
Mixes containing admixtures are
permitted an'increase in shrinkage and a
decrease in freeze thaw durability (as
indicated in Table 1 AASHTO M 194) in
comparison with mixes having no
admixtures.
Admixtures are usually accepted based on
preapproval of the material and supplier
certification. Verification tests
should be performed on liquid admixtures
to confirm that the material is the same
as that which was approved. The
identifying tests include chloride and
solids content, pH, and infrared
spectrometry.
Water reducers and retarders may be used
in bridge deck concrete to extend.the
time of set. This is especially
important when the length of placement
may result in flexural cracks created by
dead load deflections during placement.
3.10.6