ASTM D3319-11(2017)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D3319 − 11 (Reapproved 2017)
Standard Practice for the
Accelerated Polishing of Aggregates Using the British
Wheel
This standard is issued under the fixed designation D3319; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D1415 Test Method for Rubber Property—International
Hardness
1.1 This practice covers a laboratory procedure by which an
D3666 Specification for Minimum Requirements for Agen-
estimate may be made of the extent to which different coarse
cies Testing and Inspecting Road and Paving Materials
aggregates may polish.
E303 Test Method for Measuring Surface Frictional Proper-
1.2 The values stated in inch-pound units are to be regarded
ties Using the British Pendulum Tester
as the standard. The values given in parentheses are mathemati-
E501 Specification for Rib Tire for Pavement Skid-
cal conversions to SI units that are provided for information
Resistance Tests
only and are not considered standard. Regarding sieves, per
Specification E11, “The values stated in SI units shall be
3. Terminology
considered standard for the dimensions of the wire cloth
3.1 Definitions:
openings and the diameter of the wires used in the wire cloth.”
3.1.1 initial friction value (PV-i)—the initial British Pendu-
When sieve mesh sizes are referenced, the alternate inch-pound
lum Tester readings on the test specimens before they are
designations are provided for information purposes and en-
polished in the accelerated polishing machine.
closed in parentheses.
3.1.2 polish value (PV-n)—a measure of the state of polish
1.3 This standard does not purport to address all of the
reached by a test specimen subjected to the specified hours (n)
safety concerns, if any, associated with its use. It is the
of accelerated polishing using the materials, equipment, and
responsibility of the user of this standard to establish appro-
procedures described in this method. The measurement is made
priate safety and health practices and determine the applica-
using the British pendulum tester as described in 5.3 and Test
bility of regulatory limitations prior to use.
Method E303.
1.4 This international standard was developed in accor-
3.1.3 residual polish value, (RPV-n)—the residual polish
dance with internationally recognized principles on standard-
value is obtained when a constant PV-n is achieved four
ization established in the Decision on Principles for the
consecutive times with repeated swings of the pendulum.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4. Significance and Use
Barriers to Trade (TBT) Committee.
4.1 This practice simulates the polishing action of vehicular
2. Referenced Documents
traffic on coarse aggregates used in bituminous pavements.
2.1 ASTM Standards:
4.2 A polish value is determined that may be used to rate or
C778 Specification for Standard Sand
classify coarse aggregates for their ability to resist polishing
D75 Practice for Sampling Aggregates
under traffic.
NOTE 1—The quality of the results produced by this standard are
This practice is under the jurisdiction of ASTM Committee D04 on Road and
dependant upon the competence of the personnel performing the proce-
Paving Materials and is the direct responsibility of Subcommittee D04.51 on
dure and the capability, calibration, and the maintenance of the equipment
Aggregate Tests.
used. Agencies that meet the criteria of Specification D3666 are generally
Current edition approved June 1, 2017. Published June 2017. Originally
considered capable of competent and objective testing, sampling,
approved in 1974. Last previous edition approved in 2011 as D3319 – 11. DOI:
inspection, etc. Users of this standard are cautioned that compliance with
10.1520/D3319-11R17.
Specification D3666 alone does not completely ensure reliable results.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Reliable results depend on many factors: following the suggestions of
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Specification D3666 or similar acceptable guideline provides a means of
the ASTM website. evaluating and controlling some of those factors.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3319 − 11 (2017)
diameter and a larger hole provided for the value stem. This did not affect
5. Apparatus
mounting and use of the Dunlop tire. Goodyear is no longer manufactur-
5.1 Accelerated Polishing Machine —An accelerated pol-
ing this tire.
ishing machine, also known as the British wheel, and based
NOTE 4—A 1998 study conducted by the Texas Department of
upon a 1958 design by the Road Research Laboratory of Great
Transportation shows that the use of cross-hatch tire results in differential
wear of the test specimen surface that mirrors the pattern of the tire. This
Britain. This machine shall be mounted on a firm, rigid, and
differential wear pattern produces falsely higher polish values, particularly
level base. The equipment shall include the following:
for softer aggregates. Other research has shown that increased tire wear
5.1.1 Cylindrical Wheel—Hereafter referred to as the road
has an effect of accentuating the polishing of the test specimens and
wheel, and having a flat-surface periphery and of such size and
resulting in lower polish values. Laboratory control specimens should be
shape as to permit 14 specimens described below to be
used to monitor the effect of the tire wear on accelerated polishing and
clamped onto the periphery to form a continuous surface of tests results.
aggregate particles, 1 ⁄4 in. (44.45 mm) wide and 16 in.
5.1.3.3 Alternate Tire No. 3—An 8-in. (203.2-mm) diameter
(406.4 mm) in diameter.
solid rubber tire (Note 5). The tire rubber hardness shall be 69
5.1.2 A means of rotating the road wheel about its own axis
6 3 IRHD measured in accordance with Test Method D1415.
at a speed of 320 6 5 rpm.
It is necessary to move the cylindrical wheel approximately
5.1.3 A means of bringing the surface of a rubber-tired
⁄16 in. (4.76 mm) away from the polishing machine to allow
wheel 8 in. (203.2 mm) in diameter and 2 in. (50.8 mm) wide
the tire to center over the test specimens. The tire shall be
to bear on the aggregate specimens mounted on the surface of
replaced when the RPV-10 of the control specimens described
the road wheel with a total load of 88 6 1 lbf (391.44 6
in 7.2 have decreased by more than four points from the
4.45 N). The tire shall be treated, if necessary, to obtain a true
RPV-10 obtained from a new tire.
running surface. The tire shall be free to rotate about its own
axis, which should be parallel to the axis of the road wheel. The
NOTE 5—This is the tire presently supplied by the manufacturer of the
plane of rotation of the tire shall coincide with that of the road
accelerated polishing machine. Research has shown that increased tire
wear has an effect of accentuating the polishing of the test specimens and
wheel. Before a new tire is used on a test, it shall be
resulting in lower polish values. Laboratory control specimens should be
conditioned by a preliminary run of 6 h with a 150-grit silicon
used to monitor the effect of the tire wear on accelerated polishing and test
carbide using dummy specimens (extra or used) on the road
results.
wheel.
5.1.4 A means to feed the 150-grit silicon carbide abrasive
5.1.3.1 Alternate Tire No. 1—An industrial 8 by 2 pneu-
at the rate given in 8.5. The grit shall be fed continuously and
matic smooth-tread hand-truck tire (Note 2). The tire rubber
with a uniform distribution across the width of the specimens.
hardness shall be 55 6 5 IRHD measured in accordance with
The grit shall be applied directly onto the road wheel surface
Test Method D1415. The tire shall be inflated to a pressure of
45 6 2 psi (310.26 6 13.79 kPa). ahead of the point of contact with the rubber-tired wheel.
5.1.5 A means to feed the water at the rate given in 8.5 in
NOTE 2—This is the tire originally supplied with the Accelerated
such a way that the water is spread continuously and uniformly
Polishing Machine and known by the tire manufacturer’s designation
Dunlop RLI 8 by 2. Dunlop discontinued manufacturing of this tire in
over the surface of the road wheel ahead of the point of contact
February 1979. It is retained as an alternate in this practice for those users
with the rubber-tired wheel.
who may still have a supply and in the event that Dunlop should resume
manufacturing it in the future.
5.2 Metal Molds—A number of accurately machined metal
5.1.3.2 Alternate Tire No. 2—An industrial 2.80 by 4 (8 in. molds for preparing specimens. The specimen formed is 3.5 by
1.75 by 0.63 in. (88.90 by 44.45 by 16.0 mm) and shall be
OD by 4 in. ID), 4 NHS-4 ply, cross-hatch pattern tread
hand-truck tire (Notes 3 and 4). The tire shall be inflated to a curved to fit on a surface having an 8-in. (203.2-mm) radius of
curvature.
pressure of 35 6 2 psi (241.32 6 13.79 kPa).
NOTE 3—When it became known that the Dunlop tire (5.1.3.1) was no
5.3 British Pendulum Tester—A friction-measuring device.
longer being manufactured, the necessity of finding a replacement tire for
The British pendulum tester used shall conform to Test Method
the practice was evident. A search and study by the Texas State
E303.
Department of Highways and Public Transportation culminated in finding
this tire, a Goodyear Industrial All Weather Hand-Truck tire size 2.80 by 5.3.1 The slider contact path shall be 3 6 ⁄16 in. (76.20 6
4 (Goodyear product code 202-008-002), to give polish values equal to
1.59 mm).
those obtained with the Dunlop tire. A suitable inner tube such as
5.3.2 The slider width shall be 1 ⁄4 in. (31.75 mm).
Goodyear G250-4 (product code 199-010-700) is necessary. It was also
found necessary to modify the 4-in. (101.6-mm) wheel furnished with the 5.3.3 The rubber that is bonded to the slider shall be ⁄4 by
accelerated polish machine to facilitate mounting the Goodyear tire.
1 by 1 ⁄4 in. (6.35 by 25.4 by 31.75 mm).
Approximately 0.10 in. (2.54 mm) should be removed from the wheel
5.3.4 The rubber shall meet the requirements of Specifica-
tion E501.
Available from Wessex Engineering and Metal Craft Co., Ltd., Merchants
5.3.5 The zero adjustment shall be checked before and after
Barton, Frome, Somerset, England. If you are aware of alternative suppliers, please
testing the specimens and as often as the operator deems
provide this information to ASTM International Headquarters. Your comments will
necessary.
receive careful consideration at a meeting of the responsible technical committee,
which you may attend.
5.3.6 The calibration procedures of Test Method E303 shall
Supporting data have been filed at ASTM International Headquarters and may
be used. However, after calibration the small slider shall be
be obtained by requesting Research Report RR:D04-1002. Contact ASTM Customer
Service at service@astm.org. inserted.
D3319 − 11 (2017)
specimens should be 100 % polyester resin to facilitate preparation of the
5.3.7 Sanding Block—A rigid metal block with a planed
surface bearing against the road wheel.
surface of 7.5-in. (190.5-mm) radius of curvature that is
consistent with the radius of curvature of the road wheel 7.3 The aggregate to be tested shall pass the 12.5-mm
1 3
bearing surface. ( ⁄2-in) sieve and shall be retained on a 9.5-mm ( ⁄8-in.) sieve.
NOTE 7—Aggregate gradation may be varied to meet the needs of the
6. Materials and Supplies
user if reported with the test results. However, aggregates larger than
12.5 mm ( ⁄2 in.) may not be accommodated by the mold, and aggregates
6.1 Water—A supply of tap water for use where water is
smaller than 9.5 mm ( ⁄8 in.) may not be adequately bonded in the
required for any purpose in this method.
specimen molding process to be retained for the duration of the test. For
6.2 Fine Sand—A supply of fine sand for sifting into the laboratories and agencies evaluating and monitoring multiple aggregate
sources, an alternate aggregate size of passing 9.5-mm ( ⁄8-in.) sieve and
interstices of the aggregate prior to placing of the bonding
retained on a 6.3-mm ( ⁄4-in.) sieve may be used to represent the critical
material. Standard sand conforming to Specification C778 has
size of the bituminous mixture. The two aggregate sizes described should
been found suitable for this purpose.
not be used alternately for quality monitoring of friction aggregates.
6.3 Mold Release Agent—The use of a mold release agent is
7.4 Thoroughly wash and dry the aggregate to be tested at
optional. A mold release agent may be used to prevent bonding
230 6 9 °F (110 6 5 °C) to essentially constant weight.
between the mold and the bonding material. Silicon release
7.5 Coat the mold with mold release agent.
agent and paste wax as used for automobiles and floors has
been found suitable. The user should use care to prevent this 7.6 Each specimen shall contain a single layer of dry
agent from being absorbed by the aggregate, as it could affect aggregate placed by hand as densely as possible with a flat
the measured polish value. surface down to cover the bottom 3.5 by 1.75-in. (88.9 by
44.45-mm) surface of the mold.
6.4 Silicon Carbide Grit—A supply of silicon carbide grit
(150-grit size) to be used as the polishing agent. Grit should be
NOTE 8—Particles selected should be representative of the material to
be evaluated. Flat, elongated, or unusually shaped particles can cause
checked for gradation using Nos. 150-µm (No. 100), 106-µm
difficulty in placement and bonding. Misleading polish values can result
(No. 140) and 75-µm (No. 200) sieves and separated if
from inadequate surface area for polishing.
necessary to maintain a uniform gradation passing the No.
7.7 Fill the interstices between the aggregate with the fine
150-µm (No. 100) sieve and retained on the No. 75-µm (No.
sand, described in 6.2, from one-fourth to one-half of the
200) sieve.
aggregate depth.
6.5 Bonding Agent—A supply of polyester resin and catalyst
7.7.1 An optional method eliminates the sand by using a
(or another suitable bonding material, such as an epoxy resin)
viscous polyester resin. This material is described in 6.5.
having a pot life of 20 to 30 min and a curing time of 3 to 6 h.
7.8 Prepare the bonding agent described in 6.5 and in
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D3319 − 11 D3319 − 11 (Reapproved 2017)
Standard Practice for the
Accelerated Polishing of Aggregates Using the British
Wheel
This standard is issued under the fixed designation D3319; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice covers a laboratory procedure by which an estimate may be made of the extent to which different coarse
aggregates may polish.
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard. Regarding sieves, per Specification
E11, “The values stated in SI units shall be considered standard for the dimensions of the wire cloth openings and the diameter
of the wires used in the wire cloth.” When sieve mesh sizes are referenced, the alternate inch-pound designations are provided for
information purposes and enclosed in parentheses.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C778 Specification for Standard Sand
D75 Practice for Sampling Aggregates
D1415 Test Method for Rubber Property—International Hardness
D3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving Materials
E303 Test Method for Measuring Surface Frictional Properties Using the British Pendulum Tester
E501 Specification for Rib Tire for Pavement Skid-Resistance Tests
3. Terminology
3.1 Definitions:
3.1.1 initial friction value (PV-i)—the initial British Pendulum Tester readings on the test specimens before they are polished
in the accelerated polishing machine.
3.1.2 polish value (PV-n)—a measure of the state of polish reached by a test specimen subjected to the specified hours (n) of
accelerated polishing using the materials, equipment, and procedures described in this method. The measurement is made using
the British Pendulum Testerpendulum tester as described in 5.3 and Test Method E303.
3.1.3 residual polish value, (RPV-n)—the residual polish value is obtained when a constant PV-n is achieved four consecutive
times with repeated swings of the pendulum.
4. Significance and Use
4.1 This practice simulates the polishing action of vehicular traffic on coarse aggregates used in bituminous pavements.
This practice is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.51 on Aggregate
Tests.
Current edition approved June 1, 2011June 1, 2017. Published June 2010June 2017. Originally approved in 1974. Last previous edition approved in 20062011 as
D3319 – 06.D3319 – 11. DOI: 10.1520/D3319-11.10.1520/D3319-11R17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3319 − 11 (2017)
4.2 A polish value is determined that may be used to rate or classify coarse aggregates for their ability to resist polishing under
traffic.
NOTE 1—The quality of the results produced by this standard are dependant upon the competence of the personnel performing the procedure and the
capability, calibration, and the maintenance of the equipment used. Agencies that meet the criteria of Standard Practice Specification D3666 are generally
considered capable of competent and objective testing / sampling / inspection / testing, sampling, inspection, etc. Users of this standard are cautioned
that compliance with Specification D3666 alone does not completely assureensure reliable results. Reliable results depend on many factors: following
the suggestions of Specification D3666 or similar acceptable guideline provides a means of evaluating and controlling some of those factors.
5. Apparatus
5.1 Accelerated Polishing Machine —An accelerated polishing machine, also known as the British Wheel,wheel, and based
upon a 1958 design by the Road Research Laboratory of Great Britain. This machine shall be mounted on a firm, rigid, and level
base. The equipment shall include the following:
5.1.1 Cylindrical Wheel—Hereafter referred to as the road wheel, and having a flat-surface periphery and of such size and shape
as to permit 14 specimens described below to be clamped onto the periphery to form a continuous surface of aggregate particles,
1 ⁄4 in. (44.45 mm) wide and 16 in. (406.4 mm) (406.4 mm) in diameter.
5.1.2 A means of rotating the road wheel about its own axis at a speed of 320 6 5 rpm.
5.1.3 A means of bringing the surface of a rubber-tired wheel 8 in. (203.2 mm) in diameter and 2 in. (50.8 mm) wide to bear
on the aggregate specimens mounted on the surface of the road wheel with a total load of 88 6 1 lbf (391.44 6 4.45 N). 4.45 N).
The tire shall be treated, if necessary, to obtain a true running surface. The tire shall be free to rotate about its own axis, which
should be parallel to the axis of the road wheel. The plane of rotation of the tire shall coincide with that of the road wheel. Before
a new tire is used on a test, it shall be conditioned by a preliminary run of 6 h with a 150-grit silicon carbide using dummy
specimens (extra or used) on the road wheel.
5.1.3.1 Alternate Tire No. 1—An industrial 8 by 2 pneumatic smooth-tread hand-truck tire (Note 2). The tire rubber hardness
shall be 55 6 5 IRHD measured in accordance with Test Method D1415. The tire shall be inflated to a pressure of 45 6 2 psi
(310.26 6 13.79 kPa).
NOTE 2—This is the tire originally supplied with the Accelerated Polishing Machine and known by the tire manufacturer’s designation Dunlop RLI
8 by 2. Dunlop discontinued manufacturing of this tire in February 1979. It is retained as an alternate in this practice for those users who may still have
a supply and in the event that Dunlop should resume manufacturing it in the future.
5.1.3.2 Alternate Tire No. 2—An industrial 2.80 by 4 (8 in. OD by 4 in. ID), 4 NHS-4 ply, cross-hatch pattern tread hand-truck
tire (Notes 3 and 4). The tire shall be inflated to a pressure of 35 6 2 psi (241.32 6 13.79 kPa).
NOTE 3—When it became known that the Dunlop tire (5.1.3.1) was no longer being manufactured, the necessity of finding a replacement tire for the
practice was evident. A search and study by the Texas State Department of Highways and Public Transportation culminated in finding this tire, a Goodyear
Industrial All Weather Hand-Truck tire size 2.80 by 4 (Goodyear Product Codeproduct code 202-008-002), to give Polish Valuespolish values equal to
those obtained with the Dunlop tire. A suitable inner tube such as Goodyear G250-4 (Product Code(product code 199-010-700) is necessary. It was also
found necessary to modify the 4-in. (101.6-mm) wheel furnished with the Accelerated Polish Machineaccelerated polish machine to facilitate mounting
the Goodyear tire. Approximately 0.10 in. (2.54 mm) should be removed from the wheel diameter and a larger hole provided for the value stem. This
did not affect mounting and use of the Dunlop tire. Goodyear is no longer manufacturing this tire.
NOTE 4—A1998A 1998 study conducted by the Texas Department of Transportation shows that the use of cross-hatch tire results in differential wear
of the test specimen surface that mirrors the pattern of the tire. This differential wear pattern produces falsely higher polish values, particularly for softer
aggregates. Other research has shown that increased tire wear has an effect of accentuating the polishing of the test specimens and resulting in lower polish
values. Laboratory control specimens should be used to monitor the effect of the tire wear on accelerated polishing and tests results.
5.1.3.3 Alternate Tire No. 3—An 8-in. (203.2-mm) diameter solid rubber tire (Note 5). The tire rubber hardness shall be 69 6
3 IRHD measured in accordance with Test Method D1415. It is necessary to move the cylindrical wheel approximately ⁄16 in. in.
(4.76 mm) away from the polishing machine to allow the tire to center over the test specimens. The tire shall be replaced when
the RPV-10 of the control specimens described in 7.2 have decreased by more than four points from the RPV-10 obtained from
a new tire.
NOTE 5—This is the tire presently supplied by the manufacturer of the Accelerated Polishing Machine.accelerated polishing machine. Research has
shown that increased tire wear has an effect of accentuating the polishing of the test specimens and resulting in lower polish values. Laboratory control
specimens should be used to monitor the effect of the tire wear on accelerated polishing and test results.
5.1.4 A means to feed the 150-grit silicon carbide abrasive at the rate given in 8.5. The grit shall be fed continuously and with
a uniform distribution across the width of the specimens. The grit shall be applied directly onto the road wheel surface ahead of
the point of contact with the rubber-tired wheel.
5.1.5 A means to feed the water at the rate given in 8.5 in such a way that the water is spread continuously and uniformly over
the surface of the road wheel ahead of the point of contact with the rubber-tired wheel.
Available from Wessex Engineering and Metal Craft Co., Ltd., Merchants Barton, Frome, Somerset, England. If you are aware of alternative suppliers, please provide
this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may
attend.
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D04-1002. Contact ASTM Customer
Service at service@astm.org.
D3319 − 11 (2017)
5.2 Metal Molds—A number of accurately machined metal molds for preparing specimens. The specimen formed is 3.5 by 1.75
by 0.63 in. (88.90 by 44.45 by 16.0 mm) and shall be curved to fit on a surface having an 8-in. (203.2-mm) radius of curvature.
5.3 British Pendulum Tester—A friction-measuring device. The British Pendulum Testerpendulum tester used shall conform to
Test Method E303.
5.3.1 The slider contact path shall be 3 6 ⁄16 in. (76.20 6 1.59 mm).
5.3.2 The slider width shall be 1 ⁄4 in. (31.75 mm).
1 1
5.3.3 The rubber that is bonded to the slider shall be ⁄4 by 1 by 1 ⁄4 in. (6.35 by 25.4 by 31.75 mm).
5.3.4 The rubber shall meet the requirements of Specification E501.
5.3.5 The zero adjustment shall be checked before and after testing the specimens and as often as the operator deems necessary.
5.3.6 The calibration procedures of Test Method E303 shall be used. However, after calibration the small slider shall be inserted.
5.3.7 Sanding Block—A rigid metal block with a planed surface of 7.5-in. (190.5-mm) radius of curvature that is consistent with
the radius of curvature of the road wheel bearing surface.
6. Materials and Supplies
6.1 Water—A supply of tap water for use where water is required for any purpose in this method.
6.2 Fine Sand—A supply of fine sand for sifting into the interstices of the aggregate prior to placing of the bonding material.
Standard sand conforming to Specification C778 has been found suitable for this purpose.
6.3 Mold Release Agent—The use of a mold release agent is optional. A mold release agent may be used to prevent bonding
between the mold and the bonding material. Silicon release agent and paste wax as used for automobiles and floors has been found
suitable. The user should use care to prevent this agent from being absorbed by the aggregate, as it could affect the measured polish
value.
6.4 Silicon Carbide Grit—A supply of silicon carbide grit (150-grit size) to be used as the polishing agent. Grit should be
checked for gradation using Nos. 150μm150-μm (No. 100), 106 μm 106-μm (No. 140) and 75 μm 75-μm (No. 200) sieves and
separated if necessary to maintain a uniform gradation passing the No. 150 μm 150-μm (No. 100) sieve and retained on the No.
75 μm 75-μm (No. 200) sieve.
6.5 Bonding Agent—A supply of polyester resin and catalyst (or another suitable bonding material, such as an epoxy resin)
having a pot life of 20 to 30 min and a curing time of 3 to 6 h. This bonding agent shall not be so fluid as to flow through the
fine sand.
6.5.1 An optional bonding agent may be used to eliminate use of the fine sand. This bonding agent must be quite viscous so
that it will not flow completely around the aggregate particles and become part of the surface of the test specimen. Examples of
suitable materials are given in Appendix X1.
6.5.2 Follow the manufacturer’s precautions concerning storage and use of resin and catalyst.
3 3
6.6 Coarse Aggregate—Approximately a ⁄2 ft-ft (0.014 m(0.014-m ) supply of coarse aggregate to be tested and sampled in
accordance with Practice D75. The aggregate shall be normal plant run but laboratory-crushed material may be tested, if so
identified.
7. Test and Control Specimens
7.1 Five test specimens for each coarse aggregate shall be tested.
7.2 Standard laboratory control specimens shall be included in each run to develop consistency in specimen preparation and
polishing. Four control specimens shall be included with two sets containing five test specimens each for each run. Aggregates used
for fabrication of control specimens should be of consistent property and RPV-10 test history.
NOTE 6—It has been found that the polishing surface of control specimenspecimens can be successfully replicated by filling the bottom of the metal
mold with a uniform mixture of 4fou
...