31 Dec 96
(b) It is best to develop a grout job-mix formula with
water and resin additive contents below the maximum allowable
limits to allow for small additions of these ingredients in the
field if necessary to meet viscosity requirements.
(c) Lower w/c ratios are more desirable for a number of
reasons: they tend to produce grouts of higher strengths; they
reduce the chances for drying shrinkage cracking; they produce
grouts which are more consistent and better able to keep the sand
in suspension during mixing and placement.
(d) When the sand is noted to settle out of solution
during or immediately after mixing, it can be expected that
similar problems would occur in the field during construction.
This problem can be remedied by reducing the amount of sand and
increasing the amount of fly ash (both within the specified
tolerances) to produce a slightly creamier grout.
(e) When it becomes impossible to meet the viscosity
requirements within the specified limits for material quantities,
there usually is a problem with a particular ingredient. Some of
these deficiencies are detectable, while others are not. These
material deficiencies may include one or more of the following:
grout sand which is too coarse, portland cement which is highly
reactive during the early stages of the hydration process, fly
ash with excess cementitious nature. When it is possible to
isolate the problem material in these instances, the only
recourse is to substitute another material from another source
whose physical or chemical difference will likely solve the
d. Job-mix formula. The grout job-mix formula will
consist of the following information:
(1) Percentage (by weight) of each mixture ingredient
rounded to the nearest tenth of a percent.
Type and source of portland cement.
Source of fly ash, silica sand, and resin additive.
Marsh Flow Cone viscosity of job-mix-formula grout.