ASTM C1781/C1781M-14a
(Test Method)Standard Test Method for Surface Infiltration Rate of Permeable Unit Pavement Systems
Standard Test Method for Surface Infiltration Rate of Permeable Unit Pavement Systems
SIGNIFICANCE AND USE
5.1 This test method can be used for acceptance of surface infiltration of new permeable unit pavement systems.
5.2 Tests performed at the same location across a span of years may be used to detect a reduction of infiltration rate of the permeable surface, thereby identifying the need for any remedial maintenance intended to increase the infiltration rates to predefined levels.
5.3 The infiltration rate obtained by this method is valid only for the localized area of the pavement where the test is conducted. To determine the surface infiltration rate of the entire permeable pavement, multiple locations must be tested and the results averaged.
5.4 The minimum acceptable infiltration rate is typically established by the design engineer of record or the municipality and can be a function of the design precipitation event.
SCOPE
1.1 This test method covers the determination of the field surface infiltration rate of in place permeable unit pavement systems surfaced with solid interlocking concrete paving units, concrete grid paving units, or clay paving brick.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.3 The text of this test method references notes that provide explanatory material. These notes shall not be considered as requirements of the test method.
1.4 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.
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Designation:C1781/C1781M −14a
StandardTest Method for
Surface Infiltration Rate of Permeable Unit Pavement
Systems
This standard is issued under the fixed designation C1781/C1781M; 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* 2.2 Other Standards:
Federal Specification A-A-3110 (TT-P-1536A) Plumbing
1.1 This test method covers the determination of the field
Fixture Setting Compound
surface infiltration rate of in place permeable unit pavement
systems surfaced with solid interlocking concrete paving units,
3. Terminology
concrete grid paving units, or clay paving brick.
3.1 Definitions—The terms used in this test method are
1.2 The values stated in either SI units or inch-pound units
defined in Terminology C1232.
are to be regarded separately as standard. The values stated in
each system may not be exact equivalents; therefore, each
4. Summary of Test Method
system shall be used independently of the other. Combining
4.1 An infiltration ring is temporarily sealed to the surface
values from the two systems may result in non-conformance
of a permeable unit pavement system. These pavements
with the standard.
typically consist of solid concrete paving units conforming to
1.3 Thetextofthistestmethodreferencesnotesthatprovide
Specification C936, concrete grid paving units conforming to
explanatory material. These notes shall not be considered as
Specification C1319, or clay paving brick conforming to
requirements of the test method.
Specification C902 or C1272.These pavements allow drainage
1.4 This standard does not purport to address all of the
through joints between the units or through voids formed by
safety concerns, if any, associated with its use. It is the
the intersection of two or more units or intentionally manufac-
responsibility of the user of this standard to establish appro-
tured into the units. The results of this test method for unit
priate safety and health practices and determine the applica-
pavement systems can be compared to that using Test Method
bility of regulatory limitations prior to use.
C1701 for pervious concrete. After pre-wetting the test
location, a given mass of water is introduced into the ring and
2. Referenced Documents
the time for the water to infiltrate the pavement is recorded.
2.1 ASTM Standards:
The infiltration rate is calculated in accordance with 9.1.
C902 Specification for Pedestrian and Light Traffic Paving
Brick 5. Significance and Use
C920 Specification for Elastomeric Joint Sealants
5.1 This test method can be used for acceptance of surface
C936 Specification for Solid Concrete Interlocking Paving
infiltration of new permeable unit pavement systems.
Units
5.2 Tests performed at the same location across a span of
C1232 Terminology of Masonry
years may be used to detect a reduction of infiltration rate of
C1272 Specification for Heavy Vehicular Paving Brick
the permeable surface, thereby identifying the need for any
C1319 Specification for Concrete Grid Paving Units
remedial maintenance intended to increase the infiltration rates
C1701 Test Method for Infiltration Rate of In Place Pervious
to predefined levels.
Concrete
5.3 The infiltration rate obtained by this method is valid
only for the localized area of the pavement where the test is
This test method is under the jurisdiction of ASTM Committee C15 on
conducted. To determine the surface infiltration rate of the
Manufactured Masonry Units and is the direct responsibility of Subcommittee
C15.04 on Research. entire permeable pavement, multiple locations must be tested
Current edition approved Dec. 1, 2014. Published December 2014. Originally
and the results averaged.
approved in 2013. Last previous edition approved in 2014 as C1781/C1781M – 14.
DOI: 10.1520/C1781_C1781M–14A.
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 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
Standards volume information, refer to the standard’s Document Summary page on Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://
the ASTM website. dodssp.daps.dla.mil.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1781/C1781M−14a
5.4 The minimum acceptable infiltration rate is typically 8.2 Take a photograph of the immediate area to be tested to
establishedbythedesignengineerofrecordorthemunicipality document the pavement pattern and layout. Move the ring over
and can be a function of the design precipitation event. the surface of the pavement until the pattern, drainage joints
and drainage voids framed within the infiltration ring are
6. Apparatus
representative of the entire paving pattern, drainage joints and
6.1 Infiltration Ring—A cylindrical ring, open at both ends
drainage voids across the pavement surface. Set the ring on the
(See Fig. 1). The ring shall be watertight, sufficiently rigid to pavement surface and mark its location by circumscribing it
retainitsformwhenfilledwithwater,andshallhaveadiameter
with chalk or other temporary marking. Take a photograph of
of 300 6 10 mm [12.0 6 0.5 in.] with a minimum height of 50 the circumscribed chalk or temporary marking to document the
mm [2.0 in.]. The bottom edge of the ring shall be even. The
placement of the ring relative to the pavement pattern and
inner surface of the ring shall be marked or scored with two layout (see Note 2).
linesatadistanceof10and15mm[0.40and0.60in.]fromthe
NOTE 2—The procedure in 8.2 for selecting and documenting the
bottom of the ring. Measure and record the inner diameter of
placement of the infiltration ring on a representative area of the pavement
the ring to the nearest 1 mm [0.05 in.].
is sufficient in most cases for determining the infiltration rate of the
pavement.The drainage area within the infiltration ring is typically within
NOTE 1—Ring materials that have been found to be suitable include
620 % of the average drainage area of the pavement as a whole. This
steel, aluminum, rigid plastic, and PVC.
accuracy is adequate for most situations. If a more accurate quantification
6.2 Balance—A balance or scale accurate to 10 g [0.02 lb]. of the infiltration rate is needed, the procedure detailed in Appendix X1
can be used to normalize the drainage area within the infiltration ring to
6.3 Container—A cylindrical container typically made of
the average drainage area of the pavement as a whole.
plastichavingavolumeofatleast20L[5gal],andfromwhich
8.3 For solid interlocking concrete paving units and clay
water may be easily poured at a controlled rate into the
brickpaving,removeaggregatetoadepthofnogreaterthan10
infiltration ring.
mm [0.5 in.] in any joint or drainage void that will be directly
6.4 Stop Watch—Accurate to 0.1 s.
below the test ring and fill these areas with plumbers putty so
6.5 Plumbers Putty (Non-Hardening)—Meeting Specifica- that a positive seal can be made to the test ring once it is placed
onthesurface.Takecarenottoextendtheplumbersputtymore
tion C920 or Federal Specification A-A-3110.
than 10 mm [0.5 in.] inside the perimeter of the chalk line or
6.6 Water—Potable water.
other temporary marking. For concrete grid paving units,
7. Test Locations center as much of the ring as possible on the webs. For ring
locations over openings, remove any vegetation, if present,
7.1 Perform tests at multiple locations at a site as requested
directly below the test ring to a depth of no greater than 10 mm
by the purchaser of testing services. Unless otherwise
[0.5 in] and apply plumbers putty to the surface of the soil, or
specified, use the following to determine the number of tests to
to the aggregate, if present, so that a positive seal can be made
perform:
2 to the test ring once it is placed on the surface. Take care not
7.1.1 Three test locations for areas up to 2500 m [25 000
to extend the plumbers putty more than 10 mm [0.5 in.] inside
ft ].
2 the perimeter of the chalk line or other temporary marking.
7.1.2 Add one test location for each additional 1000 m [10
000 ft ] or fraction thereof.
8.4 Apply plumbers putty around the bottom edge of the
ring and place the ring onto the surface being tested. Press the
7.2 Provide at least 1 m [3 ft] clear distance between test
putty into the surface and around the bottom edge of the ring
locations, unless at least 24 h have elapsed between tests.
to create a watertight seal making sure that the putty does not
7.3 Do not test if there is standing water on top of the
extend more than 10 mm [0.5 in] inside the perimeter of the
permeable pavement. Do not test within 24 h of the last
ring. Place additional putty as needed to ensure a watertight
precipitation.
seal.
8. Procedure
NOTE 3—In a hot environment or when the surface temperature is over
38°C [100°F] plumbers putty may not adhere to the surface of the
8.1 Infiltration Ring Installation—Clean the pavement sur-
pavement easily. Therefore it is advisable to perform this test during a
face by only sweeping off trash, debris, and other non-seated
cooler temperature.
material.
8.5 Prewetting—Pour water into the ring at a rate sufficient
to maintain a head between the two marked lines. Take care to
pour the water such that it falls directly on the surface of a
paving unit and not onto the joints. This minimizes displace-
ment of jointing aggregate and any accumulated sediment in
the joints during the test (see Note 4). Use a total of 3.60 6
0.05 kg [8.0 6 0.1 lb] of water. Begin timing as soon as the
water impacts the permeable pavement surface. Stop timing
when free water is no longer present on the surface. Record the
amount of elapsed time to the nearest 0.1 second.
FIG. 1Dimensions of Infiltration Ring NOTE 4—It is recommended that the pour height be limited to a
C1781/C1781M−14a
maximum of 150 mm [6.0 in.] above the surface of the paving units to
10.1.2 Location,
minimize disruption.
10.1.3 Date of test,
8.6 Test—The test shall be started within 2 min after the
10.1.4 Age, type and thickness of paving units (label Un-
completion of the prewetting. If the elapsed time in the
known if not known),
prewetting stage is less than 30 s, then use a total of 18.00 6
10.1.5 Include a photograph of the immediate area that was
0.05 kg [40.00 6 0.1 lb] of water. If the elapsed time in the
tested to document the pavement pattern and layout and a
prewettingstageisgreaterthanorequalto30s,thenuseatotal
photograph of the circumscribed chalk or temporary marking
of 3.60 6 0.05 kg [8.0 6 0.1 lb] of water. Record the weight
to document the placement of the ring relative to the pavement
of water to the nearest 10 g [0.02 lb]. Pour the water onto the
pattern and layout,
ring at a rate sufficient to maintain a head between the two
10.1.6 Time elapsed during prewetting, s,
marked lines and until the measured amount of water has been
10.1.7 Amountofrainduringlastevent,ifknown,mm[in.],
used. Take care to pour the water such that it falls directly on
10.1.8 Weight of infiltrated water, kg [lb],
the surface of a paving unit and not onto the joints. This
10.1.9 Inside diameter of infiltration ring, mm [in.],
minimizes displacement of jointing aggregate and any accu-
10.1.10 Time elapsed during infiltration test, s,
mulated sediment in the joints during the test (see Note 5).
Begin timing as soon as the water impacts the permeable 10.1.11 Infiltration rate, mm/h [in./h], and
pavement surface. Stop timing when free water is no longer
10.1.12 Number of tests performed at each location, if
present on the surface. Record the testing duration (t)tothe
applicable.
nearest 0.1 second.
4,5
11. Precision and Bias
NOTE 5—If a sloped pavement is being measured, maintain head
between the two marked lines at the lowest point of the slope.
11.1 The following precision statements are based on dupli-
8.7 If a test is repeated at the same location, the repeat test
cate measurements done at 74 locations on 37 different
does not require pre-wetting if conducted within 5 min after permeable unit pavement systems with average infiltration
completion of the first test. If more than one test is conducted
rates ranging from 30 to 1600 in./h by two separate operators:
at a location on a given day, the infiltration rate at that location
11.1.1 The 95 % Confidence Limit (CL) for single-operator
on that day shall be calculated as the average of the two tests.
repeatability (r) averages 7.7 % with a median value of 5.9 %.
Do not repeat this test more than twice at the same location on
11.1.2 The 95 % CL for the multiple-operator reproducibil-
a given day.
ity (R) averages 19.8% with a median value of 10.0%.
8.8 When completed with testing, remove plumbers putty
11.2 Based on the average results of four measurements at
from the joints and surface, reinstate the removed aggregate
each of two locations on 37 different permeable unit pavement
jointing materials, and sweep test area clean.
systems with average infiltration rates ranging from 30 to 1600
in./h, the difference between average results at the two loca-
9. Calculation
tions averages 19.1 % with a median value of 12.2 %.
9.1 Calculatetheinfiltrationrate(I)usingconsistentunitsas
11.3 This test method has no bias because the infiltration
follows:
rate of permeable unit pavement systems is defined only in
I 5KM⁄ D * t (1)
~ !
terms of this test method.
where:
I = Infiltration rate, mm/h [in./h], 12. Keywords
M = Mass of infiltrated water, kg [lb],
12.1 clay paving units; concrete grid paving units; concrete
D = Inside diameter of infiltration ring, mm [in.],
paving units; infiltration; permeable; unit pavement systems;
t = time required for measured amount of water to infiltrate
water
the surface, s, and
K = 4 583 666 000 in SI units or 126 870 in [inch-pound]
units.
3 3 4
NOTE 6—The factor K has units of (mm s)/(kgh) [(in. s)/(lbh)] and is Supporting data have been filed at ASTM International Headquarters and may
beobtainedbyrequestingResearchReportRR:C15-1000.ContactASTMCustomer
needed to convert the recorded data (W, D, and t) to the infiltration rate I
Service at service@astm.org.
in mm/h [in./h].
Further discussion on developing the Precision and Bias Statements can be
10. Report found in: Walloch, Craig, Brown, Heather J., and Smith, David R., “Development
of a New Test Method for Determining the Surface Infiltration Rate of Permeable
10.1 Report the following information:
Unit Pavement Systems,” Symposium o
...
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: C1781/C1781M − 14 C1781/C1781M − 14a
Standard Test Method for
Surface Infiltration Rate of Permeable Unit Pavement
Systems
This standard is issued under the fixed designation C1781/C1781M; 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 test method covers the determination of the field surface infiltration rate of in place permeable unit pavement systems
surfaced with solid interlocking concrete paving units, concrete grid paving units, or clay paving brick.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.3 The text of this test method references notes that provide explanatory material. These notes shall not be considered as
requirements of the test method.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
C902 Specification for Pedestrian and Light Traffic Paving Brick
C920 Specification for Elastomeric Joint Sealants
C936 Specification for Solid Concrete Interlocking Paving Units
C1232 Terminology of Masonry
C1272 Specification for Heavy Vehicular Paving Brick
C1319 Specification for Concrete Grid Paving Units
C1701 Test Method for Infiltration Rate of In Place Pervious Concrete
2.2 Other Standards:
Federal Specification A-A-3110 (TT-P-1536A) Plumbing Fixture Setting Compound
3. Terminology
3.1 Definitions—The terms used in this test method are defined in Terminology C1232.
4. Summary of Test Method
4.1 An infiltration ring is temporarily sealed to the surface of a permeable unit pavement system. These pavements typically
consist of solid concrete paving units conforming to Specification C936, concrete grid paving units conforming to Specification
C1319, or clay paving brick conforming to Specification C902 or C1272. These pavements allow drainage through joints between
the units or through voids formed by the intersection of two or more units or intentionally manufactured into the units. The results
of this test method for unit pavement systems can be compared to that using Test Method C1701 for pervious concrete. After
pre-wetting the test location, a given mass of water is introduced into the ring and the time for the water to infiltrate the pavement
is recorded. The infiltration rate is calculated in accordance with 9.1.
This test method is under the jurisdiction of ASTM Committee C15 on Manufactured Masonry Units and is the direct responsibility of Subcommittee C15.04 on Research.
Current edition approved July 1, 2014Dec. 1, 2014. Published August 2014December 2014. Originally approved in 2013. Last previous edition approved in 20132014 as
C1781/C1781M – 13.C1781/C1781M – 14. DOI: 10.1520/C1781_C1781M–14.10.1520/C1781_C1781M–14A.
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.
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://dodssp.daps.dla.mil.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1781/C1781M − 14a
5. Significance and Use
5.1 This test method can be used for acceptance of surface infiltration of new permeable unit pavement systems.
5.2 Tests performed at the same location across a span of years may be used to detect a reduction of infiltration rate of the
permeable surface, thereby identifying the need for any remedial maintenance intended to increase the infiltration rates to
predefined levels.
5.3 The infiltration rate obtained by this method is valid only for the localized area of the pavement where the test is conducted.
To determine the surface infiltration rate of the entire permeable pavement, multiple locations must be tested and the results
averaged.
5.4 The minimum acceptable infiltration rate is typically established by the design engineer of record or the municipality and
can be a function of the design precipitation event.
6. Apparatus
6.1 Infiltration Ring—A cylindrical ring, open at both ends (See Fig. 1). The ring shall be watertight, sufficiently rigid to retain
its form when filled with water, and shall have a diameter of 300 6 10 mm [12.0 6 0.5 in.] with a minimum height of 50 mm
[2.0 in.]. The bottom edge of the ring shall be even. The inner surface of the ring shall be marked or scored with two lines at a
distance of 10 and 15 mm [0.40 and 0.60 in.] from the bottom of the ring. Measure and record the inner diameter of the ring to
the nearest 1 mm [0.05 in.].
NOTE 1—Ring materials that have been found to be suitable include steel, aluminum, rigid plastic, and PVC.
6.2 Balance—A balance or scale accurate to 10 g [0.02 lb].
6.3 Container—A cylindrical container typically made of plastic having a volume of at least 20 L [5 gal], and from which water
may be easily poured at a controlled rate into the infiltration ring.
6.4 Stop Watch—Accurate to 0.1 s.
6.5 Plumbers Putty (Non-Hardening)—Meeting Specification C920 or Federal Specification A-A-3110.
6.6 Water—Potable water.
7. Test Locations
7.1 Perform tests at multiple locations at a site as requested by the purchaser of testing services. Unless otherwise specified, use
the following to determine the number of tests to perform:
2 2
7.1.1 Three test locations for areas up to 2500 m [25 000 ft ].
2 2
7.1.2 Add one test location for each additional 1000 m [10 000 ft ] or fraction thereof.
7.2 Provide at least 1 m [3 ft] clear distance between test locations, unless at least 24 h have elapsed between tests.
7.3 Do not test if there is standing water on top of the permeable pavement. Do not test within 24 h of the last precipitation.
8. Procedure
8.1 Infiltration Ring Installation—Clean the pavement surface by only sweeping off trash, debris, and other non-seated material.
8.2 Take a photograph of the immediate area to be tested to document the pavement pattern and layout. Move the ring over the
surface of the pavement until the pattern, drainage joints and drainage voids framed within the infiltration ring are representative
of the entire paving pattern, drainage joints and drainage voids across the pavement surface. Set the ring on the pavement surface
and mark its location by circumscribing it with chalk or other temporary marking. Take a photograph of the circumscribed chalk
or temporary marking to document the placement of the ring relative to the pavement pattern and layout (see Note 2).
NOTE 2—The procedure in 8.2 for selecting and documenting the placement of the infiltration ring on a representative area of the pavement is sufficient
in most cases for determining the infiltration rate of the pavement. The drainage area within the infiltration ring is typically within 620 % of the average
FIG. 1 Dimensions of Infiltration Ring
C1781/C1781M − 14a
drainage area of the pavement as a whole. This accuracy is adequate for most situations. If a more accurate quantification of the infiltration rate is needed,
the procedure detailed in Appendix X1 can be used to normalize the drainage area within the infiltration ring to the average drainage area of the pavement
as a whole.
8.3 For solid interlocking concrete paving units and clay brick paving, remove aggregate to a depth of no greater than 10 mm
[0.5 in.] in any joint or drainage void that will be directly below the test ring and fill these areas with plumbers putty so that a
positive seal can be made to the test ring once it is placed on the surface. Take care not to extend the plumbers putty more than
10 mm [0.5 in.] inside the perimeter of the chalk line or other temporary marking. For concrete grid paving units, center as much
of the ring as possible on the webs. For ring locations over openings, remove any vegetation, if present, directly below the test
ring to a depth of no greater than 10 mm [0.5 in] and apply plumbers putty to the surface of the soil, or to the aggregate, if present,
so that a positive seal can be made to the test ring once it is placed on the surface. Take care not to extend the plumbers putty more
than 10 mm [0.5 in.] inside the perimeter of the chalk line or other temporary marking.
8.4 Apply plumbers putty around the bottom edge of the ring and place the ring onto the surface being tested. Press the putty
into the surface and around the bottom edge of the ring to create a watertight seal making sure that the putty does not extend more
than 10 mm [0.5 in] inside the perimeter of the ring. Place additional putty as needed to ensure a watertight seal.
NOTE 3—In a hot environment or when the surface temperature is over 38°C [100°F] plumbers putty may not adhere to the surface of the pavement
easily. Therefore it is advisable to perform this test during a cooler temperature.
8.5 Prewetting—Pour water into the ring at a rate sufficient to maintain a head between the two marked lines. Take care to pour
the water such that it falls directly on the surface of a paving unit and not onto the joints. This minimizes displacement of jointing
aggregate and any accumulated sediment in the joints during the test (see Note 4). Use a total of 3.60 6 0.05 kg [8.0 6 0.1 lb]
of water. Begin timing as soon as the water impacts the permeable pavement surface. Stop timing when free water is no longer
present on the surface. Record the amount of elapsed time to the nearest 0.1 second.
NOTE 4—It is recommended that the pour height be limited to a maximum of 150 mm [6.0 in.] above the surface of the paving units to minimize
disruption.
8.6 Test—The test shall be started within 2 min after the completion of the prewetting. If the elapsed time in the prewetting stage
is less than 30 s, then use a total of 18.00 6 0.05 kg [40.00 6 0.1 lb] of water. If the elapsed time in the prewetting stage is greater
than or equal to 30 s, then use a total of 3.60 6 0.05 kg [8.0 6 0.1 lb] of water. Record the weight of water to the nearest 10 g
[0.02 lb]. Pour the water onto the ring at a rate sufficient to maintain a head between the two marked lines and until the measured
amount of water has been used. Take care to pour the water such that it falls directly on the surface of a paving unit and not onto
the joints. This minimizes displacement of jointing aggregate and any accumulated sediment in the joints during the test (see Note
5). Begin timing as soon as the water impacts the permeable pavement surface. Stop timing when free water is no longer present
on the surface. Record the testing duration (t) to the nearest 0.1 second.
NOTE 5—If a sloped pavement is being measured, maintain head between the two marked lines at the lowest point of the slope.
8.7 If a test is repeated at the same location, the repeat test does not require pre-wetting if conducted within 5 min after
completion of the first test. If more than one test is conducted at a location on a given day, the infiltration rate at that location on
that day shall be calculated as the average of the two tests. Do not repeat this test more than twice at the same location on a given
day.
8.8 When completed with testing, remove plumbers putty from the joints and surface, reinstate the removed aggregate jointing
materials, and sweep test area clean.
9. Calculation
9.1 Calculate the infiltration rate (I) using consistent units as follows:
I 5 KM⁄~D * t! (1)
where:
I = Infiltration rate, mm/h [in./h],
M = Mass of infiltrated water, kg [lb],
D = Inside diameter of infiltration ring, mm [in.],
t = time required for measured amount of water to infiltrate the surface, s, and
K = 4 583 666 000 in SI units or 126 870 in [inch-pound] units.
3 3
NOTE 6—The factor K has units of (mm s)/(kgh) [(in. s)/(lbh)] and is needed to convert the recorded data (W,D, and t) to the infiltration rate I in mm/h
[in./h].
10. Report
10.1 Report the following information:
10.1.1 Identification number,
10.1.2 Location,
10.1.3 Date of test,
C1781/C1781M − 14a
10.1.4 Age, type and thickness of paving units (label Unknown if not known),
10.1.5 Include a photograph of the immediate area that was tested to document the pavement pattern and layout and a
photograph of the circumscribed chalk or temporary marking to document the placement of the ring relative to the pavement
pattern and layout,
10.1.6 Time elapsed during prewetting, s,
10.1.7 Amount of rain during last event, if known, mm [in.],
10.1.8 Weight of infiltrated water, kg [lb],
10.1.9 Inside diameter of infiltration ring, mm [in.],
10.1.10 Time elapsed during infiltration test, s,
10.1.11 Infiltration rate, mm/h [in./h], and
10.1.12 Number of tests performed at each location, if applicable.
4,5
11. Precision and Bias
11.1 The following precision statements are based on duplicate measurements done at 74 locations on 37 different permeable
unit pavement systems with average infiltration rates ranging from 30 to 1600 in./h by two separate operators:
11.1.1 The 95 % Confidence Limit (CL) for single-operator repeatability (r) averages 7.7 % with a median value of 5.9 %.
11.1.2 The 95 % CL for the multiple-operator reproducibility (R) averages 19.8% with a median value of 10.0%.
11.2 Based on the average results of four measurements at each of two locations on 37 different permeable unit pavement
systems with average infiltration rates ranging from 30 to 1600 in./h, the difference between average results at the two locations
averages 19.1 % with a median value of 12.2 %.
11.3 This test method has no bias because the infiltration rate of permeable unit pavement systems is defined only in terms of
this test method.
12. Keywords
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