in one square meter yard (25 mm l inch thickness) of open graded bituminous
mixture with 25 to 35 percent voids total mix.
2.6.2.1
Initial Laboratory Procedure
(1) Minimum sample size is 23 kg 51 lbs for cement, sand, and fly
ash; and is 4 L 1 gal for resin additive.
(2) Using the grout material proportions specified in Table V,
develop a matrix of initial job-mix formulas for laboratory
viscosity testing. The goal of the grout mix design is to produce
a material formulation, which results in a field Marsh Flow Cone
viscosity of 8.0 to 10.0 seconds. The initial formulations shall
ensure that a grout formulation can be produced with a Marsh
viscosity no greater than the 10.0 seconds maximum. This is
accomplished by testing grout formulations with relatively high
w/c ratios and the maximum allowable amount of resin additive.
(3) The grout's w/c ratio shall be between 0.65 to 0.75, unless
approved by the Contracting Officer Representative. Higher w/c
ratios are sometimes necessary to produce grout with Marsh Flow
viscosity less than the 10.0-second maximum value. Therefore, the
focus of the initial grout viscosity tests is to determine the
minimum W/C ratio that will produce a grout viscosity less than or
equal to 10.0 seconds. The resin additive serves as a plasticizer
which reduces grout viscosity while reducing the amount of water
required.
(4) The standard laboratory grout batch size should be in the 4 to
5 kg 9 to 11 lbs range. Calculate the material batch weights
based on the desired proportions. Multiple grout viscosity tests
are facilitated by first blending the dry ingredients (cement,
sand, fly ash) for each test sample and then adding the
appropriate amount of water and resin additive during the mixing
process. These dry ingredient batches should be kept in air-tight
containers to prevent loss of material or contamination before
mixing. Replicate two samples per blend for grout viscosity
testing.
2.6.2.2
Mixing
(1) The equipment needed to effectively mix the resin grout
includes a laboratory mixer equipped with a wire whip mixing
attachment and approximately 10 L 2.5 gal capacity mixing bowl, a
calibrated set of weight scales, and various small containers to
weigh and transfer mix water and resin additive.
(2) Place dry ingredients into mixing bowl and adjust the bowl
height so that the wire whip is just off of or touching the bottom
and the sides of the bowl. Begin mixing the dry ingredients at a
slow speed and immediately add the appropriate amount of water.
Once all of the water is added, speed up the mixer to a point
where the grout is being thrown onto the sides of the mixing bowl.
Mix the grout at this high speed for 5 minutes, then add the
appropriate amount of resin additive. Mix the grout again at a
high mixing speed for an additional 3 minutes before testing for
Marsh Flow viscosity.
SECTION 02746
Page 16
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