United States
Environmental Protection
Agency
Municipal Environmental Research ~ Y ;' -
Laboratory '•/>' ^ x**
Cincinnati, OH 45268 > i \*
Research and Development
EPA-600/S2-84-015 Mar. 1984
Project Summary
Compatibility of Grouts with
Hazardous Wastes
P.A. Spooner, G.E. Hunt, V.E. Hodge, P.M. Wagner, and I.R. Melnyk
A study was conducted to determine
existing information on the compatibility
of grouts with different classes of
chemicals. The data gathered can be
used as a guide for testing and selecting
grouts to be used at specific waste
disposal sites with various leachates.
The 12 types of grouts used in this
study were chosen because of their
availability and use in waterproofing
and soil consolidation projects. These
grouts are bitumen, Portland cement
Type I, Portland cement Types II and V,
clay, clay-cement, silicate, acrylamide,
phenolic, urethane, urea-formaldehyde,
epoxy, and polyester. Sixteen general
classes of organic and inorganic com-
pounds are also identified as being the
types most likely to be found in leachate
from a hazardous waste disposal site.
The known effects of each chemical
class on the setting time and durability
of each grout are identified and presented
in a matrix. These data were based on a
review of the available literature and
contact with knowledgeable persons in
industries, universities, and government
agencies. The physical and chemical
properties, reaction theory, and known
chemical compatibility of each grout
type are discussed.
Since compatibility data are not
complete for each grout type, predictions
are made where possible for the silicate
and organic polymer grouts based on
their reaction theory. These results are
also presented in a matrix.
To establish the compatibility of
chemicals with grouts, a series of
laboratory tests should be performed.
The two grout properties that must be
addressed are permeability of the
grouted soil and set time of the grout.
No established testing procedures are
identified in the literature for determin-
ing the effects of chemicals on these
grout properties. Fixed-wall and triaxial
permeameters, which are used for soil
testing, can be used for measuring the
effects of chemicals on permeability.
No single procedure applies to all grout
types for determining set time. Visual
observation is the easiest method,
though somewhat subjective.
The selection of a grout for a specific
waste site depends on its injectability,
durability, and strength. These factors
relate site hydrology, geochemistry,
and geology to grout physical and
chemical properties.
This Project Summary was developed
by EPA's Municipal Environmental
Research Laboratory. Cincinnati. OH.
to announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
The purposes of this project were to
compile data on the compatibility and
durability of grouts in the presence of
hazardous wastes and leachates, and to
summarize the test procedures available
to measure grout durability. This report
presents the basic information for
selecting grouts based on their compati-
bility with chemicals; it does not specifi-
cally address stability of grouts with
respect to ground conditions, other factors
that affect durability, or grout-specific
properties that ultimately influence the
grout selection.
Grouting has been used for years by the
construction industry as a technique for
consolidating and sealing ground masses.
The principal use for grouting has been
for large dam and tunneling projects.
Although grouting is still very much an art
rather than an exact engineering discipline,
much has been published on properties.
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applications, and testing of grouts. Nearly
all of this information, however, has
focused on the use of grout in construction
rather than in remedial work at hazardous
waste disposal sites. Adaptations to
waste sites could include forming a tie-in
between a slurry wall and highly fractured
or weathered bedrock, or sealing leaks in
aquitards resulting from exploratory bore
holes or improperly installed wells.
The grouts used for soil consolidation
and groundwater control are emulsions,
polymers, and particle suspensions.
These materials are generally water-
based solutions of sufficiently low
viscosity to penetrate rock and soil voids.
Particulate grouts composed of cements
or clays or both constitute approximately
95% of all grout used. The remaining 5%
is primarily silicate grout, though bitumen
and organic polymer grouts do have some
limited use for water sealing. These
proportions, however, may not be appli-
cable to hazardous waste sites.
The testing procedures in current use
are not yet standardized and do not deal
directly with the grout's ability to set up in
and withstand attack from hazardous
wastes and leachates. Many of the
available data regarding the chemical
compatibility of grouts do not specify
chemical concentrations, and when they
do, they generally are listed as "dilute" or
"high-strength," without actual concen-
trations. Furthermore, chemical compati-
bility data for chemical grouts often
consisted of data for mortar or pipe-sealing
applications in which the chemical
concentrations would likely be higher
than that for soil sealing.
A key aspect of this report is a series of
matrices presenting the known and
predicted effects of different chemical
groups on set time and durability of the
various grouts currently in use. The
chemical grouts contain most of the
compounds found in hazardous wastes
and associated leachate. For our purposes,
the compounds are all assumed to act
independently.
This study centered on collecting or
organizing and analyzing existing infor-
mation on the compatibility and durability
of grouts with various classes of chemicals.
Where sufficient information was not
available, compatibility determinations
were based on chemistry and reaction
theories of the various grouts and
chemical classes.
Compatibility with Wastes
Through a detailed evaluation of
available information on the effects of
chemicals on grout performance, a series
of matrices were developed that summarize
and define the compatibilities of grouts
with various chemical groups. The
information was gathered through a
detailed review of the published literature
and through contacts with representatives
from universities, industries, trade
associations, and government agencies.
From the information obtained, matrices
were developed to summarize and define
the compatibilities of grouts with chemical
groups. The matrices provide a step-by-
step analysis of the data, moving from
general to specific information. Most of
the information found detailed the effects
of pure chemicals or did not specify
concentration. Thus the data are assumed
to be related to the effects of undiluted
chemicals. While leachates generally
contain low levels of compounds, there
can be instances where grouts will come
into contact with high concentrations of
chemicals such as organic solvents.
Based on the information search, six
grout categories were chosen for study:
bitumen; Portland cement Types I, II, and
V; clay (bentonite); clay-cement; silicates;
organic polymers (including acrylamide,
phenolic, urethane, urea-formaldehyde,
epoxy, and polyester).
To simplify the matrix, the chemical
universe was divided into 16 basic
groups representing the types of compounds
found in landfills. The organic categories
were chosen by functional groups or
structural characteristics. The inorganics
were divided into acid, base, and silt
categories. Grouping organics by function-
al groups is useful because although
physical properties may differ, the
interaction of any functional group with
other groups remains essentially the
same.
Two general characteristics of grouts
are affected by the presence of chemicals:
set time and durability. Numeric codes
define the effects on set time as follows:
1) no significant effect, 2) increased set
time, and 3) decreased set time. Alphabet-
ic codes are used to convey the durability
of the set grout in the presence of
chemicals: a) no significant effect, b)
increased durability, c) decreased dura-
bility in the short-term, and d) decreased
durability in the long-term. The matrix
codes only address changes in set time or
durability as a result of exposure to
chemicals. The codes do not address
specific mechanisms that lead to the
changes or mechanisms other than
chemical action.
Table 1 presents a detailed matrix in
which the chemical groups listed are the
16 mentioned above. The groups have
been divided into organic and inorganic
categories. The data contained in the
matrix were derived from both general
and specific information regarding classes A
of chemicals. Many of the available data "
refer to the effect of general classes and
not specific chemicals. They were derived
from available literature and conversations
with persons knowledgeable about
grouts. Table 1 does not contain any pre-
dictions or estimates of chemical/grout
interactions.
To fill the data information gaps, a
matrix was developed that contains
predictions or estimates of grout/chemical
interactions (Table 2). The predictions
are based on the chemical structure,
reaction theory, and estimated behavior
of grouts in the presence of the various
chemical groups. To make these estimates,
the following assumptions were made:
• Typical landfill leachate has a high
salt content, approximately 1%
organic compounds concentration,
less than 1% metal ions concentra-
tion, and a pH between 3 and 11.
• Groundwater is static (no turbulence)
and is a multicomponent dilute
solution in which interactions between
co/nponents do not occur; interactions
may occur between these components
and the grout, however.
• Complete reactions between organic
polymer grouts and their curing
agents do not occur, and other
unreacted constituents will remain. A
Test Procedures
To establish the compatibility of grouts
with the compounds contained in ground-
water, a series of tests must be performed.
The two properties that must be investigated
are permeability of grouted mass and
setting time in the contaminated environ-
ment. No established procedures exist for
these tests, but the following methods
have been identified as potential proce-
dures.
To measure permeability and observe
the limits established by Darcy's Law,
constant-head and variable-head tests
have been developed. Three basic cate-
gories of testing equipment are: fixed
wall, triaxial, and consolidation permeameter
cells.
The advantages of constant-head
permeameters are the simplicity of data
interpretation and reduced confusion
resulting from the changing volume of air-
filled voids when the soil is not saturated.
The major advantage of variable-head
testing is that small flows can be
measured more easily. Disadvantages
are longer times and gas bubbles that
may develop in the sample when gas
pressure is used to reduce testing time.
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Table 1. Interactions Between Grouts and Specific Chemical Groups
Grout Type
Portland Cement
Chemical Group
Organic Compounds
Alcohols and Glycols
Aldehydes and Ketones
Aliphatic and Aromatic
Hydrocarbons
Amides and Amines
Chlorinated Hydrocarbons
Ethers and Epoxides
Heterocyclics
Nitrites
Organic Acids and Acid
Chlorides
Organometallics
Phenols
Organic Esters
Inorganic Compounds
Heavy Metals Salts and
Complexes
Inorganic Acids
Inorganic Bases
Inorganic Salts
Bitumen
Pa
Pd*
Pd
7
Pd
7
7
7
Pa
7
Pd
P
Pd
Pa§o
Pa
Pd
q>
Pd
7
2a
7
2d
P
p
7
1d
7
Id
P
2c
Id
la
2c
I
Pd
7
2P
7
2d
p
p
p
1d
7
7
?
2a
1a
/at
2a
Clay (Bentonite)
Pd
Pd
Pd
7
p
P
Pd
p
Pd
7
Pd
p
Pd
PC*
?c>
2d
!
i
(0
O
Pd
7
7
7
7
7
7
7
Pd
7
Pd
7
2c
PC
Pd
Pd*
Silicate
7
7
7
7
P
7
7
7
?a
7
7
la
3?
3a
2c
3P
I
Pd
Pa
Pa
7
Pa
Pa
Pa
7
2a
7
7
P
2P
2c
3d
3d
tb
P
3a
Pdt
7
Pd
p
7
7
Pa
?
2a
?
?
Pa§
Pd
3a#
Polymers
Urethane
3a
Pd
?a
3P
Pa
Pa
P
p
2a
p
?c
P
7
2c
Pd
Pd
Urea- formaldeh yde
p
P
2a
P
2a
Pd
7
p
la
P
P
P
Pa
1d
2c
Pa
|
Pa
P
Pd
p
Pd
P
7
P
Pd
P
7
P
P
Pa%
Pa
Pa
Polyester
Pa
P
Pd
P
Pd
7
7
P
Pd
7
P
P
P
Pa*
Pd
Pa
KEY: Compatibility Index
Effect on Set Time
1 No significant effect
2 Increase in set time (lengthen or prevent from setting)
3 Decrease in set time
Effect on Durability
a No significant effect
b Increase durability
c Decrease durability (destructive action begins within a short time
period)
d Decrease durability (destructive action occurs over a long time
period)
* Except sulfates, which are PC
t Except-KoH and NaOH, which are 1d
J Low molecular weight polymers only
§ Non-oxidizing
* Non-oxidizing, except HF
o Except concentrated acids
• Except aldehydes which are 1a
# Except bleaches which are 3d
* For modified bentonites. Pd
P Data Unavailable
Fixed-wall permeameter cells are the
simplest. In this permeameter, the
sample is contained in a fixed-wall
cylinder supported by a porous disc or
screen. To prevent swelling, a plate can
be clamped against the sample's upper
surface. This apparatus can be used
either as a constant- or variable-head
system. The advantage of this technique
is that the apparatus is readily available
and easy to use. The disadvantage is
possible leakage between the sample and
the permeameter wall. Consolidation
permeameter cells are similar to fixed-
wall cells except that a load is placed on
the top of the sample to create a seal
between the sample and the cell walls.
In a triaxial permeameter cell, a cylin-
drical sample is confined in a rubber
membrane and subjected to an external
hydrostatic pressure during the perme-
ability test. The advantages of using this
type of permeameter are the reduced
chances of liquid flow around the sample
and the fact that it allows for complete
saturation of the sample. The disadvan-
tage is that it has a relatively complex
procedure and requires expensive equip-
ment.
Several potential sources of error are
associated with all permeability tests:
Incomplete saturation of the sample or
accumulation of gas bubbles, leakage
around the sides of the sample, and
changes in temperature.
Grouts to be tested must first be mixed
with a material that resembles soil. Sand
is usually used for this purpose. Though
no current method exists for preparing
the grouted sand sample, an ASTM
procedure has been proposed.
The moment at which a grout sets can
be expressed as a specific point in the
evaluation of a property characteristic.
Unfortunately, no single property can be
used for all grouts. The simplest method
for determining set time is the interval of
time after which the grout can no longer
be transferred from one container to
another. A number of devices have been
used that will give quantitative measure-
ments by measuring changes in viscosity
with time.
To measure the effects of chemicals on
setting time, the chemicals should be
mixed with the grouts. In the case of pure
grouts, the chemicals can be mixed
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Table 2. Predicted Grout Compatibilities
Grout Type
Polymers
Effect on Set Time
1 No significant effect
2 Increase in set time (lengthen or prevent from setting}
3 Decrease in set time
Effect on Durability
a No significant effect
b Increase durability
c Decrease durability (destructive action begins within a short time
period)
d Decrease durability (destructive action occurs over a long time
period)
* // metal salts are accelerators
*• If metal is capable of acting as an accelerator
? Determination of compatibility could not be made based on a valiable
information
— Data available
t
Chemical Group
Organic Compounds
Alcohols and Glycols
Aldehydes and Ketones
Aliphatic and Aromatic
Hydrocarbons
Amides and Amines
Chlorinated Hydrocarbons
Ethers and Epoxides
Heterocyclics
Nitrites
Organic Acids and Acid
Chlorides
Organometallics
Phenols
Organic Esters
Inorganic Compounds
Heavy Metal Salts and
Complexes
Inorganic Acids
Inorganic Bases
Inorganic Salts
j
7a
7a
1d
3a
1d
1a
1d
1a
7—
7a
7a
—
— a
—
—
— d
Acrylamide
1—
? —
7—
3d
7 —
7 —
1 —
3?
—
3a
1a
?
— ?
—
—
—
Phenolic
3b
—
P—
3b
?—
/a
la
la
3—
P
—
p
p
2—
3—
—
Urethane
—
J—
7—
—a
7—
7 —
7a
7a
2—
—
2—
?
3>?
—
? —
p—
I
1
1?
p
—
7a
—
? —
7a
7a
—
7a
7a
?
? —
—
—
P—
I
7—
7a
7—
7a
7—
7a
7a
7a
?—
7a
7a
?
3?
1—
? —
P—
Polyester
J—
la
7—
3a
1—
1a
1a
la
7—
3*?
1?
Id
3?
1—
1 —
3*—
KEY: Compatibility Index
directly into the grout. If the grout is
injected into sand, the sand can be
saturated with the chemical. By compar-
ing the effects of mixing the grout with
pure water or the chemical, the chemical
effect on set time can be determined.
Grout Selection
The success of a grouting operation
depends on the selection of the proper
grouting materials for the specific area to
be treated. Thus the properties of the
grout must be matched with the hydrogeo-
logical and geological properties of the
area to be grouted. This task can be
accomplished with a step-by-step analysis
of three basic grout properties: injectability,
strength, and durability. In addition to
these properties, other factors not
directly related to the geological setting
(cost and toxicity, for example) must also
be considered and may be more important
than the properties.
By comparing each property to the
conditions present in the geological
structure, the proper type of grout can be
selected. But the selection of a specific
formulation for field application requires
the assistance of experts in the grouting
field.
The injectability of a grout is controlled
either by its viscosity or particle size. This
property will dictate the grout's ability to
penetrate a soil/rock structure. The
lower the viscosity, the finer the voids
that can be penetrated. Also, the smaller
the particle size in suspension grouts, the
smaller the voids that can be penetrated.
Grouts with a viscosity of less than 2
centipoise (cP), such as many of the
chemical grouts, can penetrate strata
with permeabilities of less than ~\Q'5
cm/sec. Higher-viscosity grouts, like
particulate and some chemical grouts
with a viscosity greater than 10 cP, can
only penetrate coarse strata with perme-
abilities greater than 10~2 cm/sec.
For suspension grouts, the particle size
also influences the ability to penetrate
voids. A general rule of thumb sometimes
used for determining a grout's penetration
ability equates grain size of the particles
within the grout to soil particles within
the stratum. This relationship is:
DIB
where: Di5= diameter of grains in the
stratum where 15% of the
soil mass is finer
DBS = diameter of particles within
in the grout where 85%
of the particles are finer
This ratio should be at least 19 and
preferably greater than 24 to ensure
adequate penetration of grout into soil
voids.
Once a grout has set in the voids in the
ground, it must be able to resist hydrostatic
forces in the pores that would tend to
displace it. This ability will depend on the
mechanical strength of the grout and can
be estimated by the grout's shear
strength.
The shear strength of a grout will
depend not only on its class, but also on
its formulation. Thus a class of grouts
such as silicates can possess a wide
range of mechanical strengths depending
on the concentration and type of chemicals
used in its formulation. The strength of
the gel, then, can be adjusted within
limits to the specific situation.
For permanent control of groundwater
or leachate movement, the grout must
not deteriorate because of the influence
of the soil or groundwater chemistry.
Thus in the selection process, the short-
and long-term durability of the grout must
be evaluated.
Deterioration of a grouted area over
time can occur through several physical/
chemical mechanisms. The grout can be
-------
dissolved or structurally changed by
water or chemical action. Also, removal
of water from the grout through desiccation
or syneresis can shrink it. These factors
can weaken a grout, leading to increased
permeability.
Short-term deterioration of the grout
can be caused by rapid chemical degradation
or by an incorrect setting time. The effect
on setting time can be caused by a
miscalculation of the grout formulation,
dilution of the grout by groundwater, or
changes caused by chemicals contained
within the grouted strata.
The effect that groundwater will have
on grout stability depends on the class
and formulation of the material. For areas
that have large groundwater flow rates,
the grout must be able to quickly set
before it is diluted or washed away. The
set time is often a controllable parameter.
Water can also redissolve some of the
grout constituents because of the reversi-
bility of many of the polymerization or
gelation reactions.
The actual durability of a grout in a
specific geological setting should be
determined from laboratory testing.
Grout selection could also be based on
the results of field applications in similar
geologic settings.
Another grout selection factor that
might be considered is the toxicity of the
solidified grout and its components. This
factor will be important if the aquifer with
which the grout comes into contact is a
potential drinking water source. The oral
toxicity of most of the compounds used in
grouts have been determined, as have
many of the values for the set grout. The
specific grout application and the amount
of unreacted material must also be
considered.
The cost of the grouting operation is
also a selection factor. Material costs and
injection costs should both be considered.
The expense of chemical grouts is offset
to some degree by the fact that particulate
grouts may be three to five times more
costly to pump into the ground.
Conclusions
Little actual chemical compatibility
testing has been performed on grouts.
Many of the data presented here have
been taken from related uses of similar
materials and not specifically from the
testing of grouts in contaminated soils.
Significant data were collected, for
example, from research in waste solidifi-
cation and encapsulation techniques.
Few documented cases exist of the use of
grouts and grouting technology for
hazardous waste site remediation.
Laboratory testing of grout/chemical
compatibility centers on evaluating two
general factors: the effect of chemicals on
grout setti ng ti me a nd how long the grout
will remain effective after prolonged
exposure to the chemicals. Protocols for
conducting these pa rticulartests have yet
to be developed.
Selection of a grout for a particular
purpose depends primarily on site
characteristics and the material's inject-
ability, strength, permeability, and dura-
bility. In addition, costs and toxicities of
grouting materials are major factors.
Suspension grouts (cement, clay, and
cement/clay) are the most common,
accounting for approximately 95 % of all
grout used. Silicate grouts are the most
commonly used chemical grouts, followed
by acrylamides and urethanes. Other
minor grout types are used in less than
1% of grout applications.
Recommendations
During the course of this study, several
areas were identified that lacked available
information but are important in determining
the usefulness of grouts at hazardous
waste disposal sites. Areas recommended
for further research include:
• Grout specifications and applications
• Compatibility of grouts with chemi-
cals
• Long-term stability of grout
• Compatibility testing procedures.
Very few data were found on the
formulation of currently used or potentially
usable grouts and their specific areas of
application. Information on the chemical
make-up and specific area of application
of each type of grout must be known to
select the grouts and testing procedures
to be included in a laboratory evaluation
program. The specific areas that should
be investigated include:
• Areas of potential and actual grout
application at waste disposal sites
• Information on actual grout formu-
lations currently used
Very limited information exists on the
effects of chemicals on grouts used at
disposal sites. Moreover, most compati-
bility information deals with the effects of
high concentrations of simple chemicals.
To evaluate the effects of leachates on
grouts, information on grout compatibility
with low chemical concentrations and
chemical mixtures must be known. Thus
areas for further research including a
pilot-scale program are:
• Effects of dilute chemicals on grouts
• Effects of chemical mixtures on
grouts
• Effects of actual leachates on grouts
Information is needed on the ability of
grout to withstand leachate, water,
hydrostatic pressure, and biodegradation
once it is in the ground. Such data are
very limited in the literature and are
essential to obtaining a permanent seal.
Thus the environmental effects on the
structural integrity of grouts should be
further researched in both a laboratory
and pilot-scale program.
Currently no established compatibility
test procedures exist for grouts, but the
potential exists for using the same types
of test procedures developed for evaluating
soils, bentonite slurries, and cement.
Permeability measurement techniques
have been developed in all of these areas,
and they are directly applicable to grout
compatibility evaluations. Setting time
measurements, on the other hand, are a
little more difficult to apply because of
the varying nature of the set grouts. For
both types of measurements, different
laboratory techniques must be used for
testing the different grout types be-
cause of variation in physical and chem-
ical properties. Further research areas
include:
• Evaluation and selection of test
procedures for permeability
• Evaluation and selection of set time
test procedures
The full report was submitted in
fulfillment of Contract No. 68-03-3113
by JRB Associates under the sponsorship
of the U.S. Environmental Protection
Agency.
-------
P. A. Spooner, G. E. Hunt. V. E. Hodge, and P. M. Wagner are with JRB Associates,
McLean, VA 22102; the EPA author I. Melnyk is with the Municipal Environ-
mental Research Laboratory, Cincinnati, OH 45268.
Herbert R. Pahren is the EPA Project Officer (see below).
The complete report, entitled "Compatibility of Grouts with Hazardous Wastes,"
(Order No. PB 84-139 732; Cost: $16.00, subject to change) will be available only
from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Municipal Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
•&U.S. GOVERNMENT PRINTING OFFICE: 1986/646-116/20736
-------
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
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Penalty for Private Use $300
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