ASTM D7760-12

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Designation: D7760 − 12
Standard Test Method for
Measurement of Hydraulic Conductivity of Tire Derived
Aggregates Using a Rigid Wall Permeameter
This standard is issued under the fixed designation D7760; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1.1 This test method covers laboratory measurement of the
bility of regulatory limitations prior to use.
hydraulic conductivity (also referred to as coeffıcient of per-
meability) of water-saturated tired derived aggregates (TDA)
2. Referenced Documents
obtained from scrap tires using a rigid-wall permeameter. The
2.1 ASTM Standards:
tire materials covered in this method include tire chips, tire
D653Terminology Relating to Soil, Rock, and Contained
shreds, and tire derived aggregate (TDA) as described in
Fluids
PracticeD6270withparticlesizesrangingfromapproximately
D2434Test Method for Permeability of Granular Soils
12 to 305 mm. Whole scrap tires are not included in this
(Constant Head)
standard. A clear trend between hydraulic conductivity and
D3740Practice for Minimum Requirements for Agencies
shred size has not been established at a given vertical pressure
2 Engaged in Testing and/or Inspection of Soil and Rock as
for shreds ≥50 mm (1).
Used in Engineering Design and Construction
1.2 A single- or dual-ring permeameter may be used in the
D4753Guide for Evaluating, Selecting, and Specifying Bal-
tests. A dual-ring permeameter may be preferred over a
ances and Standard Masses for Use in Soil, Rock, and
single-ring permeameter to take into account and prevent
Construction Materials Testing
short-circuiting of permeant along the sidewalls of the per-
D6026Practice for Using Significant Digits in Geotechnical
meameter. The effects of sidewall flow is more significant at
Data
highstressesandwhenthecelldiameterislessthan6timesthe
D6270Practice for Use of Scrap Tires in Civil Engineering
particle size (1).
Applications
1.3 The test method is used under constant head conditions.
3. Terminology
1.4 Water is used as the permeant with the test method.
3.1 Definitions:
1.5 Test Method D2434 also can be used for determination
3.1.1 Forcommondefinitionsoftermsinthisstandard,refer
of hydraulic conductivity of TDAs with sizes smaller than 19
to Terminology D653.
mm under constant head conditions in a rigid-wall permeame-
3.1.2 For definitions of terms related to scrap tires, refer to
ter. Method D2434 includes the use of a permeameter with a
Practice D6270.
single ring.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 hydraulic conductivity, k—(also referred to as coeffı-
1.6 The standard units for the hydraulic conductivity values
cient of permeability or permeability) the rate of discharge of
are the SI units, unless other units are specified. Hydraulic
water under laminar flow conditions through a unit cross-
conductivity has traditionally been expressed in cm/s in the
sectional area of porous medium under a unit hydraulic
U.S.,eventhoughtheofficialSIunitforhydraulicconductivity
gradient and standard temperature conditions (20 °C).
is m/s.
3.2.2 hydraulic gradient, i—the change in total head (head
1.7 This standard does not purport to address all of the
loss, ∆h) per unit distance (L) in the direction of fluid flow, in
safety concerns, if any, associated with its use. It is the
which i = ∆h/L.
3.2.3 permeameter—the apparatus (cell) containing the test
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
specimen in a hydraulic conductivity test.
Rock and is the direct responsibility of Subcommittee D18.14 on Geotechnics of
Sustainable Construction.
Current edition approved June 1, 2012. Published August 2012. DOI: 10.1520/ For referenced ASTM standards, visit the ASTM website, www.astm.org, or
D7760–12 contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
The boldface numbers in parentheses refer to a list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7760 − 12
4. Significance and Use 5.2.1 System De-airing—The hydraulic system shall be
designed to facilitate rapid and complete removal of free air
4.1 This test method is used to measure one-dimensional
bubblesfromflowlines.Thiscanbeaccomplishedforexample
vertical flow of water through initially saturated TDAs under
by using properly sized tubing and ball valves, and fittings
an applied hydraulic gradient. Hydraulic conductivity is re-
without pipe threads. Properly sized components are small
quired in various civil engineering applications of TDAs.
enough to prevent entrapment of air bubbles, but are large
4.2 TDAs are to be tested at a unit weight and under an
enough not to cause head losses as described in 6.1.
overburden pressure representative of field conditions. Data
5.3 Flow-Measurement System—Flow-measurement system
from the literature indicate a reduction in hydraulic conductiv-
is used to determine the amount of inflow and outflow from a
ity with increasing vertical pressure (1).
specimen during a test. The measurement device shall allow
4.3 Use of a dual-ring permeameter is included in this test
for the measurement of the quantity of flow (both inflow and
methodinadditiontoasingle-ringpermeameter.Thedual-ring
outflow) over an interval of time to within 65% or better
permeameterallowsforminimizingpotentialadverseeffectsof
accuracy. Flow-measurement system may consist of a gradu-
sidewallleakageonmeasuredhydraulicconductivityofthetest
ated accumulator, Mariotte bottle, vertical standpipe in con-
specimens.The use of a bottom plate with an inner ring with a
junction with an electronic pressure transducer, electromag-
diametersmallerthanthediameterofthepermeameterandtwo
netic flow meter, or other volume-measuring device that has
outflow ports (one from the inner ring, one from the annular
the resolution required to determine flow to the accuracy
space between the inner ring and the permeameter) allows for
provided above. In most cases, these devices are common to
separating the flow from the central part of the test specimen
the hydraulic system.
from the flow near the sidewall of the permeameter.
5.3.1 De-airing and Dimensional Stability of the System—
4.4 Darcy’s law is assumed to be valid, flow is assumed to
The flow-measurement system shall contain a minimum of
be laminar (Reynolds number less than approximately
dead space and shall be equipped to allow for complete and
2000–3000), and the hydraulic conductivity is assumed to be
rapid de-airing. Dimensional stability of the system with
essentially independent of hydraulic gradient. The validity of
respect to changes in pressure shall be ensured by using a stiff
Darcy’s law may be evaluated by measuring the hydraulic
flow-measurement system that includes glass pipe or rigid
conductivity of a specimen at three hydraulic gradients. The
metallic or thermoplastic tubing.
discharge velocity (v = k × i) is plotted against the applied
5.4 Vertical Pressure Application System—The system for
hydraulicgradient.Iftheresultingrelationshipislinearandthe
applying vertical pressure on the TDA specimen in the per-
measuredhydraulicconductivityvaluesaresimilar(i.e.,within
meameter(ifused)shallallowforapplyingandcontrollingthe
25%), then Darcy’s law may be taken as valid.
pressure to within 65% or better accuracy. The vertical
NOTE 1—The quality of the result produced by this standard is
pressure application system may include a dead-weight load
dependent of the competence of the personnel using this standard and the
application setup; a hydraulic load application system; or any
suitability of the equipment and facilities.Agencies that meet the criteria
of Practice D3740 are generally considered capable of competent and other system that allows for application of the desired level of
objective testing/sampling/inspection/etc. Users of this standard are cau-
pressure to a specimen via the top of the specimen.
tioned that compliance with Practice D3740 does not in itself assure
5.5 Permeameter—The permeameter shall consist of a per-
reliable results. Reliable results depend on many factors; Practice D3740
provides a means of evaluating some of these factors. meameter cell and attached equipment that allow for connect-
ing the permeameter to the hydraulic system, the flow-
5. Apparatus
measurement system, and the pressure application system, as
5.1 Schematics of the various components of two setups
well as provisions to support a specimen and to permeate the
used to determine hydraulic conductivity of TDAs using
specimen. The permeameter cell shall consist of a rigid mold,
rigid-wall permeameters under constant head conditions are
coverplate,baseplate,andattachmentstoholdthecomponents
provided for single-ring and dual-ring devices in Fig. 1(a) and
together without leakage during a test. The diameter of the
(b), respectively.
permeameter shall be determined based on the nominal size
5.2 Constant-Head Hydraulic System—The hydraulic sys- (defined as the average particle size that comprises more than
temisusedtoapply,maintain,andmeasureheadsandresulting 50% of a TDAsample per Practice D6270) of the TDAto be
tested. A permeameter diameter at least 6 times the nominal
hydraulic gradients in a test. The hydraulic system mainly
consists of reservoirs that hold water and associated piping, particlesizehasbeenshowntobeadequate (1).Apermeameter
tubing, valves, and connections. Pressure application setups with a diameter of 0.30 m and a height of 0.12 m was
may also be used to pressurize influent and effluent liquids, in demonstrated to be effective for testing tire chips with dimen-
particular to apply high hydraulic gradients. The system shall sions of 38 × 76 mm (2).
allow for maintaining constant hydraulic head to within 65% 5.5.1 Rigid Permeameter Mold—The permeameter cell
or better accuracy during a test. The system shall allow for shall consist of a rigid-wall mold into which the tire specimen
measurement of the constant head to within 65% or better to be tested is placed and in which the test specimen is
accuracy during a test. The head shall be measured with a permeated. The mold shall be constructed of a rigid material
graduated pipette, engineer’s scale, pressure gauge, electronic such as steel, aluminum, brass, or plastic that will not be
pressure transducer, or any other device that has the resolution damagedduringplacement/compressionofthespecimeninthe
requiredforthedeterminationofheadtotheaccuracyprovided mold. The mold shall be cylindrical in shape. The cross-
above. sectional area along the direction of flow shall not vary by
D7760 − 12
FIG. 1 Example Test Setups
more than 62% and the height shall not vary by more than both.Hydraulicgradientmeasurementsmaybemadeusingthe
61%. The permeameter shall be designed and operated such stand pipe piezometer attachments on the sidewall.
that permeant water flows downward through the test 5.5.2 Top Plate—The top plate shall be constructed of a
specimen, although upward flow may be used if the top of the rigid material that does not react adversely with the test
specimen is protected from upward movement by a rigid material or permeant water.The top plate may be sealed to the
porouselement.Provisionsmaybeincludedalongthesidewall rigid-wallpermeametercellusinganO-ringorsimilarprevent-
of the permeameter to directly attach the mold to the constant- ingleakageortheplatemaybeperforatedandnotsealedtothe
head hydraulic system or the flow-measurement system or permeametercellbasedonthedesignofthetestsetup.Asealed
D7760 − 12
top plate is used when the hydraulic or flow measurement nearest 0.1 g. The mass of specimens greater than 999 g shall
systems or both are connected to the top plate (or the be determined to the nearest g.
permeameter cell) through leak-proof ports or valves, whereas
5.8 Time Measurement Devices—Devices to measure the
a perforated top plate is used when water is ponded directly
duration of each permeation trial, such as a clock with second
above a specimen. The top plate shall be designed to ensure
hand or stop watch (or equivalent), or both.
that flow through the test specimen is one-dimensional.
5.9 Vacuum Pump—A vacuum pump may be used to assist
5.5.3 Base Plate—The bottom plate shall be constructed of
with de-airing of permeant water or saturation of specimens.
a rigid material that does not react adversely with the test
material or permeant water. The base plate shall be sealed to
6. Procedure
the rigid-wall permeameter cell using an O-ring or similar
6.1 Determination of Head Losses—Excessive head losses
preventing leakage. The plate shall be designed to ensure that
in the tubes, valves, and porous end pieces may limit flow in
flow through the test specimen is one-dimensional. If a
the test system and lead to errors in measurements in the tests.
dual-ring permeameter is used, the diameter of the inner ring
Head losses shall be determined using the actual permeant
shallbe80%ofthediameterofthepermeametermoldandthe
water that will be used in a test program. The permeameter
inner ring shall be concentric to the mold. The height of the
shall be assembled without a specimen and then water shall be
inner ring shall be 5% of the height of the mold.
passed through the system to determine head losses in the
5.5.4 Porous End Pieces—The specimen shall be overlain
system. The hydraulic heads that will be used in testing a
andunderlainbyporousendpieces.Porousendpiecesshallbe
specimen shall be applied, and the rate of flow shall be
used to distribute water uniformly over the surfaces of a test
measured to within 65% or better accuracy. This rate of flow
specimen (that is, areas perpendicular to the direction of flow).
shall be at least ten times greater than the rate of flow that is
Porous end pieces shall be constructed of a material that does
measured when a specimen is placed inside the permeameter
not react with the specimen or the permeant liquid. Geosyn-
and the same hydraulic heads are applied.
thetic materials such as geonets and drainage geocomposites
may be used when high flow through the system is required.
6.2 Specimen Setup:
The end pieces shall have plane and smooth surfaces and be 6.2.1 Soak the po
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