ASTM D5874-24

Standard Test Methods for Determination of the Impact Value (IV) of a Soil

SIGNIFICANCE AND USE
5.1 Impact Value, as determined using the standard 4.5 kg (10 lbm) hammer, has direct application to design and construction of pavements and a general application to earthworks compaction control and evaluation of strength characteristics of a wide range of materials, such as soils, soil aggregates and stabilized soil. Impact Value is one of the properties used to evaluate the strength of a layer of soil up to about 150 mm (6 in.) in thickness using a 50 mm (2 in.) diameter hammer or up to 380 mm (15 in.) in thickness using a 130 mm (5 in.) diameter hammer, and by inference to indicate the compaction condition of this layer. Impact Value reflects and responds to changes in physical characteristics that influence strength. It is a dynamic force-penetration property and may be used to set a strength parameter.  
5.2 This test method provides immediate results in terms of IV and may be used for the process control of pavement or earthfill activities where the avoidance of delays is important and where there is a need to determine variability when statistically based quality assurance procedures are being used.  
5.3 This test method does not provide results directly as a percentage of compaction but rather as a strength index value from which compaction may be inferred for the particular moisture conditions. From observations, strength either remains constant along the dry side of the compaction curve or else reaches a peak and, for both cases, declines rapidly with increase in water content beyond a point slightly dry of optimum water content, at approximately 0.5 percent. This is generally between 95 and 98 % maximum dry density (see Fig. 1 and Fig. 2). An as-compacted target strength in terms of IV may be designated from laboratory testing or field trials as a strength to achieve in the field as the result of a compaction process for a desired density and water content. If testing is performed after compaction when conditions are such that the water content has c...
SCOPE
1.1 These test methods cover the determination of the Impact Value (IV) of a soil either in the field or a test mold, as follows:  
1.1.1 Field Procedure A—Determination of IV alone, in the field.  
1.1.2 Field Procedure B—Determination of IV and water content, in the field.  
1.1.3 Field Procedure C—Determination of IV, water content and dry density, in the field.  
1.1.4 Mold Procedure—Determination of IV of soil compacted in a mold, in the lab.  
1.2 Units—The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information only and are not considered standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard.  
1.3 The standard test method, using a 4.5 kg (10 lbm) hammer, is suitable for, but not limited to, evaluating the strength of an unsaturated compacted fill, in particular pavement materials, soils, and soil-aggregates having maximum particle sizes less than 37.5 mm (1.5 in.).  
1.4 By using a lighter 0.5 kg (1.1 lbm) or 2.25 kg (5 lbm) hammer, this test method is applicable for evaluating lower strength soils such as fine grained cohesionless, highly organic, saturated, or highly plastic soils having a maximum particle size less than 9.5 mm (0.375 in.), or natural turfgrass.  
1.5 By using a heavier 10 kg (22 lbm) or 20 kg (44 lbm) hammer, this test method is applicable for evaluating harder materials at the top end the scales or beyond the ranges of the standard and lighter impact soil testers.  
1.6 By performing laboratory test correlations for a particular soil using the 4.5 kg (10 lbm) hammer, IV may be correlated with an unsoaked California Bearing Ratio (CBR) or may be used to infer percentage compaction. The IV of the 0.5 kg (1.1 lbm) and 2.25 kg (5 lbm) hammers may be independently correlated to an unsoaked CBR or used to infer the percentage compaction for lower strength soils...

General Information

• Status: Published
• Publication Date: 31-Jan-2024
• ICS: 13.080.20 - Physical properties of soils
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.08 - Special and Construction Control Tests

Relations

• Replaces: ASTM D5874-16 - Standard Test Methods for Determination of the Impact Value (IV) of a Soil
• Effective Date: 01-Feb-2024
• Referred By: ASTM F355-23 - Standard Test Method for Impact Attenuation of Playing Surface Systems, Other Protective Sport Systems, and Materials Used for Athletics, Recreation and Play
• Effective Date: 01-Feb-2024
• Referred By: ASTM F1702-10(2018) - Standard Test Method for Measuring Impact-Attenuation Characteristics of Natural Playing Surface Systems Using a Lightweight Portable Apparatus
• Effective Date: 01-Feb-2024

Overview

ASTM D5874-24: Standard Test Methods for Determination of the Impact Value (IV) of a Soil establishes procedures for evaluating soil strength using dynamic force-penetration techniques. The Impact Value (IV), also referred to as the Clegg Impact Value (CIV), offers immediate, quantifiable feedback on the compaction and strength characteristics of soils and soil-aggregate materials in both laboratory and field settings. The standard is essential for civil engineering, pavement design, earthwork construction, and quality assurance in soil compaction processes.

Key Topics

• Impact Value (IV) Measurement: The standard describes methods for determining the IV of soils using hammers of various masses and sizes, depending on the type and strength of the material. The main device is a 4.5 kg (10 lbm) hammer, but lighter (0.5 kg, 2.25 kg) and heavier (10 kg, 20 kg) options are provided for a range of applications.
• Field and Laboratory Procedures: ASTM D5874-24 includes detailed procedures for both field testing and mold-based laboratory testing.
  • Field Procedure A: IV determination only
  • Field Procedure B: IV and water content
  • Field Procedure C: IV, water content, and dry density
  • Mold Procedure: IV of soil compacted in a test mold
• Interpretation of Results: IV is reported as a dynamic strength index and can be correlated to unsoaked California Bearing Ratio (CBR) or inferred percentage compaction if laboratory correlation exists for the specific material.
• Compaction and Moisture Considerations: The Impact Value responds to both compaction and moisture content, reflecting changes in soil physical properties. The value can help establish field compaction targets and monitor the effectiveness of compactive efforts.

Applications

• Pavement and Roadway Construction: The test is widely used to assess the compaction quality and structural capacity of subgrade and pavement layers. IV testing speeds up control processes by providing results on-site, reducing the need for laboratory density testing in some contexts.
• Earthworks Compaction Control: The IV test is valuable for immediate process control during earthfill, embankment, or construction activities, enabling timely adjustments and ensuring uniform compaction.
• Soil Strength Evaluation: The method applies to a broad spectrum of soils and soil-aggregate mixtures, including stabilized soils and natural or artificial turfgrass. Lighter hammers provide sensitivity for softer or more fragile soils, while heavier hammers target denser or harder materials.
• Quality Assurance: When statistically-based quality assurance procedures are in place, IV testing helps monitor material variability and supports rapid decision-making on site.
• Turf and Recreational Surface Testing: The light and medium hammers are suitable for evaluating hardness in sports fields and golf courses, where surface condition impacts user performance and safety.

Related Standards

ASTM D5874-24 references several related ASTM standards important for comprehensive soil evaluation and quality assurance:

• ASTM D653: Terminology Relating to Soil, Rock, and Contained Fluids
• ASTM D698 / D1557: Test Methods for Laboratory Compaction Characteristics of Soil
• ASTM D1883: Test Method for CBR of Laboratory-Compacted Soils
• ASTM D1556, D2167, D2937: Methods for measuring soil density in the field
• ASTM D2216, D4643, D4959: Methods for determining soil water content
• ASTM D3740: Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection
• ASTM D6026: Practice for Using Significant Digits and Data Records in Geotechnical Data

---

By adhering to ASTM D5874-24, engineers and construction professionals can achieve standardized, repeatable soil strength measurement and compaction control, leading to improved quality and durability of earthworks and pavement structures. This standard ensures compatibility with international best practices and supports efficient, data-driven workflow on construction sites.

Standards Content (Sample)

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.
Designation: D5874 − 24
Standard Test Methods for
Determination of the Impact Value (IV) of a Soil
This standard is issued under the fixed designation D5874; 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* lbm) and 2.25 kg (5 lbm) hammers may be independently
correlated to an unsoaked CBR or used to infer the percentage
1.1 These test methods cover the determination of the
compaction for lower strength soils.
Impact Value (IV) of a soil either in the field or a test mold, as
follows: 1.7 All observed and calculated values shall conform to the
1.1.1 Field Procedure A—Determination of IV alone, in the guidelines for significant digits and rounding established in
field. Practice D6026.
1.1.2 Field Procedure B—Determination of IV and water
1.8 For purposes of comparing a measured or calculated
content, in the field.
value(s) with specified limits, the measured or calculated
1.1.3 Field Procedure C—Determination of IV, water con-
value(s) shall be rounded to the nearest decimal or significant
tent and dry density, in the field.
digits in the specified limits.
1.1.4 Mold Procedure—Determination of IV of soil com-
1.8.1 The procedures used to specify how data are collected/
pacted in a mold, in the lab.
recorded or calculated in this standard are regarded as the
1.2 Units—The values stated in SI units are to be regarded industry standard. In addition, they are representative of the
as the standard. The values given in parentheses are provided significant digits that generally should be retained. The proce-
for information only and are not considered standard. Report- dures used do not consider material variation, purpose for
ing of test results in units other than SI shall not be regarded as obtaining the data, special purpose studies, or any consider-
nonconformance with this standard. ations for the user’s objectives; it is common practice to
increase or reduce significant digits of reported data to be
1.3 The standard test method, using a 4.5 kg (10 lbm)
commensurate with these considerations. It is beyond the scope
hammer, is suitable for, but not limited to, evaluating the
of this standard to consider significant digits used in analysis
strength of an unsaturated compacted fill, in particular pave-
methods for design.
ment materials, soils, and soil-aggregates having maximum
NOTE 1—The equipment and procedures contained in this test method
particle sizes less than 37.5 mm (1.5 in.).
are similar to those developed by B. Clegg in the 1970s at the University
of Western Australia, Perth, Western Australia, Australia. Impact Value is
1.4 By using a lighter 0.5 kg (1.1 lbm) or 2.25 kg (5 lbm)
also commonly known as Clegg Impact Value (CIV).
hammer, this test method is applicable for evaluating lower
1.9 This standard does not purport to address all of the
strength soils such as fine grained cohesionless, highly organic,
safety concerns, if any, associated with its use. It is the
saturated, or highly plastic soils having a maximum particle
responsibility of the user of this standard to establish appro-
size less than 9.5 mm (0.375 in.), or natural turfgrass.
priate safety, health, and environmental practices and deter-
1.5 By using a heavier 10 kg (22 lbm) or 20 kg (44 lbm)
mine the applicability of regulatory limitations prior to use.
hammer, this test method is applicable for evaluating harder
1.10 This international standard was developed in accor-
materials at the top end the scales or beyond the ranges of the
dance with internationally recognized principles on standard-
standard and lighter impact soil testers.
ization established in the Decision on Principles for the
1.6 By performing laboratory test correlations for a particu-
Development of International Standards, Guides and Recom-
lar soil using the 4.5 kg (10 lbm) hammer, IV may be correlated
mendations issued by the World Trade Organization Technical
with an unsoaked California Bearing Ratio (CBR) or may be
Barriers to Trade (TBT) Committee.
used to infer percentage compaction. The IV of the 0.5 kg (1.1
2. Referenced Documents
2.1 ASTM Standards:
This test method is under the jurisdiction of ASTM Committee D18 on Soil and
Rock and is the direct responsibility of Subcommittee D18.08 on Special and
Construction Control Tests. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2024. Published March 2024. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1995. Last previous edition approved in 2016 as D5874 – 16. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D5874-24. the ASTM website.
*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
D5874 − 24
D653 Terminology Relating to Soil, Rock, and Contained 3.2.5 impact soil tester, n—testing apparatus used to obtain
Fluids an IV of a soil.
D698 Test Methods for Laboratory Compaction Character-
3.2.6 impact value (IV), n—the value expressed in units of
istics of Soil Using Standard Effort (12,400 ft-lbf/ft (600
tens of gravities (g) and reported in whole numbers derived
kN-m/m ))
from the peak deceleration of a 4.5 kg (10 lbm) instrumented
D1556/D1556M Test Method for Density and Unit Weight
compaction hammer 50 mm (2.0 in.) in diameter free falling
of Soil in Place by Sand-Cone Method (Withdrawn 2024)
450 mm (18 in.).
D1557 Test Methods for Laboratory Compaction Character-
3.2.7 in-service target IV, n—the desired strength, in terms
istics of Soil Using Modified Effort (56,000 ft-lbf/ft
of IV, to be achieved in the field for a particular material and
(2,700 kN-m/m ))
construction process once the road is opened to traffic and has
D1883 Test Method for California Bearing Ratio (CBR) of
reached equilibrium. This may also be referred to as the
Laboratory-Compacted Soils
in-service target strength.
D2167 Test Method for Density and Unit Weight of Soil in
Place by the Rubber Balloon Method (Withdrawn 2024)
3.2.8 light impact value (IV/L), n—the IV derived from
D2216 Test Methods for Laboratory Determination of Water
using a 0.5 kg (1.1 lbm) mass hammer 50 mm (2.0 in.) in
(Moisture) Content of Soil and Rock by Mass
diameter free falling 300 mm (12 in.).
D2937 Test Method for Density of Soil in Place by the
3.2.9 medium impact value (IV/M), n—the IV derived from
Drive-Cylinder Method
using a 2.25 kg (5 lbm) mass hammer 50 mm (2.0 in) in
D3740 Practice for Minimum Requirements for Agencies
diameter free falling 450 mm (18 in.).
Engaged in Testing and/or Inspection of Soil and Rock as
Used in Engineering Design and Construction
4. Summary of Test Method
D4643 Test Method for Determination of Water Content of
Soil and Rock by Microwave Oven Heating
4.1 The test apparatus is placed on the material to be tested
D4959 Test Method for Determination of Water Content of
either in a mold or on naturally occurring or compacted soil in
Soil By Direct Heating
the field. The hammer is raised to a set height and allowed to
D6026 Practice for Using Significant Digits and Data Re-
free fall. The instrumentation of the test apparatus displays a
cords in Geotechnical Data
value in tens of gravities (g) of the peak deceleration of the
D6938 Test Methods for In-Place Density and Water Content
hammer’s impact as recorded by an accelerometer fitted to the
of Soil and Soil-Aggregate by Nuclear Methods (Shallow
top of the hammer body. A total of four blows of the hammer
Depth)
are applied on the same spot to determine the IV for each test
performed.
3. Terminology
4.2 Lighter hammers at 0.5 kg (1.1 lbm) or 2.25 kg (5 lbm)
3.1 Definitions:
may be used for softer conditions or fragile materials instead of
3.1.1 For definitions of common technical terms used in this
the 4.5 kg (10 lbm) standard hammer to determine the IV.
standard, refer to Terminology D653.
When used, the resulting value is termed the Light Impact
3.2 Definitions of Terms Specific to This Standard: Value (IV/L) for the 0.5 kg (1.1 lbm) hammer or Medium
Impact Value (IV/M) for the 2.25 kg (5 lbm) hammer.
3.2.1 as-compacted target IV, n—the desired strength, in
terms of IV, to be achieved in the field for a particular material
4.3 Larger, heavier hammers at 10 kg (22 lbm) or 20 kg (44
and construction process at the as-compacted moisture condi-
lbm) may be used instead of the 4.5 kg (10 lbm) standard
tion. This may also be referred to as the as-compacted target
hammer to determine the IV for harder conditions or to test
strength.
through a larger zone both horizontally and vertically. When
3.2.2 dried-back target IV, n—the desired strength, in terms
used, the resulting value is termed the Heavy Medium Heavy
of IV, to be achieved in the field for a particular material and
Impact Value (IV/HMH) for the 10 kg (22 lbm) hammer or
construction process prior to continuing with a subsequent
Heavy Impact Value (IV/H) for the 20 kg (44 lbm) hammer.
layer, or sealing, or opening to traffic, after moisture has left the
system through evaporation and/or drainage. This may also be
5. Significance and Use
referred to as the dried-back target strength.
5.1 Impact Value, as determined using the standard 4.5 kg
3.2.3 heavy impact value (IV/H), n—the IV derived from
(10 lbm) hammer, has direct application to design and con-
using a 20 kg (44 lbm) mass hammer 130 mm (5 in.) in
struction of pavements and a general application to earthworks
diameter free falling 300 mm (12 in.).
compaction control and evaluation of strength characteristics
3.2.4 heavy medium heavy impact value (IV/HMH), n—the
of a wide range of materials, such as soils, soil aggregates and
IV derived from using a 10 kg (22 lbm) mass hammer 130 mm
stabilized soil. Impact Value is one of the properties used to
(5 in.) in diameter free falling 300 mm (12 in).
evaluate the strength of a layer of soil up to about 150 mm (6
in.) in thickness using a 50 mm (2 in.) diameter hammer or up
to 380 mm (15 in.) in thickness using a 130 mm (5 in.)
diameter hammer, and by inference to indicate the compaction
The last approved version of this historical standard is referenced on
www.astm.org. condition of this layer. Impact Value reflects and responds to
D5874 − 24
changes in physical characteristics that influence strength. It is
a dynamic force-penetration property and may be used to set a
strength parameter.
5.2 This test method provides immediate results in terms of
IV and may be used for the process control of pavement or
earthfill activities where the avoidance of delays is important
and where there is a need to determine variability when
statistically based quality assurance procedures are being used.
5.3 This test method does not provide results directly as a
percentage of compaction but rather as a strength index value
from which compaction may be inferred for the particular
moisture conditions. From observations, strength either re-
mains constant along the dry side of the compaction curve or
else reaches a peak and, for both cases, declines rapidly with
increase in water content beyond a point slightly dry of
optimum water content, at approximately 0.5 percent. This is
generally between 95 and 98 % maximum dry density (see Fig.
1 and Fig. 2). An as-compacted target strength in terms of IV
may be designated from laboratory testing or field trials as a
strength to achieve in the field as the result of a compaction
process for a desired density and water content. If testing is
performed after compaction when conditions are such that the
water content has changed from the critical value, determina-
tion of the actual water content by laboratory testing enables
the field density to be inferred from regression equations using
IV, density and water content.
FIG. 2 Illustration of Target IV for Material with Pronounced Peak
NOTE 2—Impact Value may be used as a means to improve the
compaction process by giving instant feedback on roller efficiency,
uniformity, confirming the achievement of the target strength, and by
inference the achieved density. When inferring density solely from IV,
however, it is considered as only indicative of density.
5.4 This test method may be used to monitor strength
changes during a compaction process or over time due to
seasonal, environmental or traffic changes.
NOTE 3—For in-place soil strength evaluation where there may be a dry
and hard surface layer (crust), testing both the crust and the underlying
layer may be required.
5.5 The standard instrument is based on a 4.5 kg (10 lbm)
compaction hammer using a 450 mm (18 in.) drop height. The
hammer is equipped with an accelerometer and instrumented
using a peak hold electronic circuit to read the peak decelera-
tion on impact. The circuitry is filtered electronically to remove
unwanted frequencies and the peak deceleration is displayed in
units of ten gravities (g) with the output below units of ten
gravities truncated.
5.6 The peak deceleration on which IV is derived represents
the area under the deceleration versus time curve which for
most soils may be assumed as half a sinusoid. Applying double
integration provides first the time-velocity relationship and
second the time-penetration relationship. As force is also
FIG. 1 Illustration of Target IV for Material with No Peak directly related to deceleration, the IV therefore represents both
D5874 − 24
stress and penetration and may be taken as a direct measure- istics and the performance or injury potential to participants.
ment of stiffness or strength (see Fig. 3). Medium Impact Value is preferable over Light Impact Value in
relation to assessing natural turf where there is thicker thatch
5.7 Impact Value may be correlated with an unsoaked CBR.
and longer grass whereas Light Impact Value is preferable for
5.8 Impact Value may be expressed as a hammer modulus,
finely mown grass surfaces where less indentation than that of
analogous with elastic modulus or deformation modulus.
the medium hammer is desired, such as testing of grass tennis
courts and golf putting greens.
5.9 The lighter hammers use the same accelerometer and
instrumentation as the standard hammer. Utilization of lighter
5.12 The medium hammer has application to testing of
masses at 0.5 kg (1.1 lbm) and 2.25 kg (5 lbm) results in more
earthworks materials.
sensitivity for lower strength materials compared to the stan-
5.13 The heavy medium heavy hammer uses the same
dard mass; that is, the scale is expanded with these lighter
accelerometer and instrumentation as the standard hammer and
hammer masses and provides more definition on softer
tests through a larger zone both horizontally and vertically than
materials, along with there being less indentation into the
the lighter impact soil testers because of its larger diameter
material. To avoid confusion, the IV of the lighter hammers is
mass. The IV of the heavy medium heavy hammer is notated as
notated as IV/L for the 0.5 kg (1.1 lbm) mass and as IV/M for
IV/HMH.
the 2.25 kg (5 lbm) mass.
5.14 The Heavy Medium Heavy Impact Value has applica-
5.10 The medium hammer provides a sensitivity between
tion to testing the same materials as those tested by the
that of the standard hammer and light hammer.
standard, light, medium and heavy impact soil testers.
5.11 Light Impact Value and Medium Impact Value have
5.15 The heavy hammer uses the same accelerometer and
application to testing of sand, peat and for natural and artificial
instrumentation as the standard hammer and tests through a
recreation turf hardness evaluation, where it is that the hard-
larger zone both horizontally and vertically as compared to the
ness of recreation turf surfaces affects ball bounce character-
50 mm (2 in.) diameter impact soil testers. The IV of the heavy
hammer is notated as IV/H.
5.16 The Heavy Impact Value has application to testing the
same materials as those tested by the standard, light, medium,
and heavy medium heavy impact soil testers but the greater
mass of this impact soil tester provides less sensitivity of the
output so is applicable for harder materials at the top end the
scales or beyond the ranges of the lighter impact soil testers.
NOTE 4—The quality of the results produced by this test method is
dependent on the competence of the personnel performing it and the
suitability of the equipment and facilities used. Agencies that meet the
criteria of Practice D3740 are generally considered capable of competent
and objective testing. Users of this test method are cautioned that
compliance with Practice D3740 does not in itself ensure reliable results.
Reliable results depend on many factors; Practice D3740 provides a means
of evaluating some of those factors.
6. Interferences
6.1 Due to the laws of physics and soil mechanics, a
significant change in the output occurs as a result of a
significant change in the mass and/or diameter and/or drop
height and/or design and/or construction of an impact soil
tester. Therefore, where there is a significant change in any of
the above parameters between impact soil testers, the output of
one cannot be taken as one-for-one with the output of another.
A significant change in any of these parameters however allows
for the Impact Value concept to be extended to a greater
number of situations and applications while utilizing the same
instrumentation. The different signifiers for the Impact Value
output as given herein not only help to avoid confusion but
provide a shorthand means to identify the output of an impact
soil tester according to the particular mass and diameter of
hammer and its standard drop height.
6.2 The maximum of the first four blows has been found
through experiment and practice to be the simplest means by
which to obtain consistent results. Analysis of the blow count
FIG. 3 Development of Force-Penetration from Deceleration Ver-
sus Time has shown that the first blow or two may be considered as a
D5874 − 24
test comparison with the 152.4 mm (6 in.) mold of Test Method D1557
seating procedure as they create a compacted wedge or
that there is no significant difference in the IV results.
hemisphere of soil that is subsequently forced into the body of
the soil causing an increase in deceleration, that is, an increase
8. Procedure
in IV, as successive blows are applied. In general, deceleration
remains practically unchanged after the third or fourth blow
8.1 Operational Verification Checks—Perform operational
with additional blows continuing to produce a constant amount
verification checks at the commencement of any testing
of penetration. If lower values occur with subsequent blows,
program, after repair or fresh calibration, or when the instru-
this is due apparently to the hammer striking the sides of the
ment is suspect using the operational check ring as follows.
indentation or by loose material falling onto the strike surface
8.1.1 Place the ring on a dry, grease free, smooth, hard
causing a bias in this direction.
surface of a solid massive object, such as a concrete floor over
ground. Place the guide tube centrally over the ring and drop
7. Apparatus
the hammer five times from the set height mark as described in
7.1 Impact Soil Tester—A test apparatus consisting of a A2.1.3 for the standard 4.5 kg (10 lbm) hammer, A2.1.4 for the
hammer, guide tube and electronic instrumentation. Detailed light 0.5 kg (1.1 lbm) hammer, A2.1.5 for the medium 2.25 kg
(5 lbm) hammer or A2.1.6 for the heavy medium heavy 10 kg
information on the apparatus is contained in Annex A1. A
typical configuration for a 50 mm (2 in.) diameter hammer that (22 lbm) hammer and 20 kg (44 lbm) heavy hammer. Operate
the instrumentation so as to obtain five separate readings. If
utilizes a tubular handle is illustrated in Fig. 4.
this operational check procedure gives significantly different
7.2 Mold—A 152.4 6 0.7 mm (6.000 6 0.026 in.) diameter
values than shown on the ring, examine the dryness,
mold conforming to the requirements of Test Methods D698
cleanliness, smoothness and firmness of the support for the ring
Procedure C, D1557 Procedure C or D1883 with a spacer disk.
and the ring itself, check the external signal cable for damage
7.2.1 Molds of other, typically larger, dimensions or that of
in relation to open circuiting or short circuiting or poor
D1883 without a spacer disk may be used but such shall be
connection(s), review the operational check procedure and
reported accordingly in the report.
rerun the check at the same or another location. If the ring
NOTE 5—For a particular material, the smaller 101.6 mm (4 in.) mold
value is not satisfactorily achievable, consult the manufacturer.
of Test Method D698 may be used if it has been proven by a laboratory
NOTE 6—To avoid the possibility of damage to the electronics or the
hammer, it is recommended that the impact soil tester is not used directly
on hard surfaces such as concrete or otherwise in such a way on materials
that it would give results of more than 100 IV (1000 g).
NOTE 7—The impact energy provided by an impact soil test hammer
with a mass greater than 0.5 kg can cause damage to materials such as
brick or concrete paving slabs or smoothly prepared hard turf surfaces
such as grass tennis courts or golf putting greens.
8.2 Determine an IV as follows:
8.2.1 The peak deceleration that is the highest of four
successive blows on a test spot is taken as the IV.
8.2.2 Impact Values obtained from other blow counts, or an
average thereof, shall be reported accordingly in the report.
8.3 Field Procedure A—If necessary, prepare the surface to
be tested by lightly scuffing with the foot to remove loose
surface material. Before beginning a test ensure that the
hammer strike face is clean of any soil or foreign material
build-up and that the guide tube is reasonably clean so as not
to restrict a free fall. Place the impact soil tester in position
with the guide tube base set on the ground. Steady the guide
tube to hold vertical in place, activate the instrumentation and
apply four free falling blows in succession from the set height
of drop. The highest value of the four blows is taken as the IV.
NOTE 8—Methods of securing the guide tube in a vertical position
include placing a foot on the guide tube base and steadying the guide tube
with the knee, or by using a spare hand instead of placing a foot on the
base if the design allows. It is suggested if securing the base with a foot
to use the hand on the same side of the body for raising the hammer.
NOTE 9—For sloping sites, a level test surface may need to be prepared
so that the guide tube base rests on the surface with the guide tube as near
to vertical as possible.
8.4 Field Procedure B—Follow Field Procedure A but
determine the water content of the material at a location 100
FIG. 4 Illustration (Cross Section) of the Standard 4.5 kg Impact
Soil Tester with Hammer at Rest in the Guide Tube mm (4 in.) to 150 mm (6 in.) from the edge of the guide tube
D5874 − 24
flange. Determine the water content according to the applicable each specimen using 100 % compactive effort according to the
test methods listed in 2.1. nominated compaction method. Obtain an IV according to 8.6
for each molded specimen to produce a curve of IV versus
8.5 Field Procedure C—Follow Field Procedure B but
water content. Determine the As-Compacted Target IV from
determine also the density of the material at a location 100 mm
the correlation curve at the point at which an increase in water
(4 in.) to 150 mm (6 in.) from the edge of the guide tube flange.
content results in a corresponding loss of strength. If requested,
Determine the density according to the applicable test methods
obtain corresponding unsoaked CBRs on duplicate specimens
listed in 2.1.
and plot the IV versus CBR relationship.
8.6 Mold Procedure—Obtain a soil sample representative of
9.1.3 As-Compacted Target IV from a Range
...

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: D5874 − 16 D5874 − 24
Standard Test Methods for
Determination of the Impact Value (IV) of a Soil
This standard is issued under the fixed designation D5874; 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 These test methods cover the determination of the Impact Value (IV) of a soil either in the field or a test mold, as follows:
1.1.1 Field Procedure A—Determination of IV alone, in the field.
1.1.2 Field Procedure B—Determination of IV and water content, in the field.
1.1.3 Field Procedure C—Determination of IV, water content,content and dry density, in the field.
1.1.4 Mold Procedure—Determination of IV of soil compacted in a mold, in the lab.
1.2 Units—The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for
information only and are not considered standard. Reporting of test results in units other than SI shall not be regarded as
nonconformance with this standard.
1.3 The standard test method, using a 4.5 kg (10 lbm) hammer, is suitable for, but not limited to, evaluating the strength of an
unsaturated compacted fill, in particular pavement materials, soils, and soil-aggregates having maximum particle sizes less than
37.5 mm (1.5 in.).
1.4 By using a lighter 0.5 kg (1.1 lbm) or 2.25 kg (5 lbm) hammer, this test method is applicable for evaluating lower strength
soils such as fine grained cohesionless, highly organic, saturated, or highly plastic soils having a maximum particle size less than
9.5 mm (0.375 in.), or natural turfgrass.
1.5 By using a heavier 10 kg (22 lbm) or 20 kg (44 lbm) hammer, this test method is applicable for evaluating for harder materials
at the top end the scales or beyond the ranges of the standard and lighter impact soil testers.
1.6 By performing laboratory test correlations for a particular soil using the 4.5 kg (10 lbm) hammer, IV may be correlated with
an unsoaked California Bearing Ratio (CBR) or may be used to infer percentage compaction. The IV of the 0.5 kg (1.1 lbm) and
2.25 kg (5 lbm) hammers may be independently correlated to an unsoaked CBR or used to infer the percentage compaction for
lower strength soils.
1.6 The values stated SI are to be regarded as the standard. The values stated in parentheses are given for information only.
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.08 on Special and Construction
Control Tests.
Current edition approved Jan. 1, 2016Feb. 1, 2024. Published January 2016March 2024. Originally approved in 1995. Last previous edition approved in 20072016 as
D5874 – 02(2007). DOI: 10.1520/D5874-16.16. DOI: 10.1520/D5874-24.
*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
D5874 − 24
1.7 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026.
1.8 For purposes of comparing,comparing a measured or calculated value(s) with specified limits, the measured or calculated
value(s) shall be rounded to the nearest decimal or significant digits in the specified limits.
1.8.1 The procedures used to specify how data are collected/recorded or calculated,calculated in this standard are regarded as the
industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures
used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s
objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these
considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design.
NOTE 1—The equipment and procedures contained in this test method are similar to those developed by B. Clegg in the 1970s at the University of Western
Australia, Perth, Western Australia, Australia. Impact Value is also commonly known as Clegg Impact Value (CIV).
1.9 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 healthsafety, health, and environmental practices and determine
the applicability of regulatory limitations prior to use.
NOTE 1—The equipment and procedures contained in this test method are similar to those developed by B. Clegg in the 1970s at the University of Western
Australia, Nedlands, Australia. Impact Value is also commonly known as Clegg Impact Value (CIV).
1.10 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:
D653 Terminology Relating to Soil, Rock, and Contained Fluids
3 3
D698 Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lbf/ft (600 kN-m/m ))
D1556D1556/D1556M Test Method for Density and Unit Weight of Soil in Place by Sand-Cone Method (Withdrawn 2024)
D1557 Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft (2,700
kN-m/m ))
D1883 Test Method for California Bearing Ratio (CBR) of Laboratory-Compacted Soils
D2167 Test Method for Density and Unit Weight of Soil in Place by the Rubber Balloon Method (Withdrawn 2024)
D2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass
D2937 Test Method for Density of Soil in Place by the Drive-Cylinder Method
D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in
Engineering Design and Construction
D4643 Test Method for Determination of Water Content of Soil and Rock by Microwave Oven Heating
D4959 Test Method for Determination of Water Content of Soil By Direct Heating
D6026 Practice for Using Significant Digits and Data Records in Geotechnical Data
D6938 Test Methods for In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth)
3. Terminology
3.1 Definitions:
3.1.1 Except as listed For definitions of common technical terms used in 3.2, all definitions are in accordance with this standard,
refer to Terminology D653.
3.2 Definitions of Terms Specific to This Standard:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
D5874 − 24
3.2.1 as-compacted target IV, n—the desired strength, in terms of IV, to be achieved in the field for a particular material and
construction process,process at the as-compacted moisture condition. This may also be referred to as the as-compacted target
strength.
3.2.2 dried-back target IV, n—the desired strength, in terms of IV, to be achieved in the field for a particular material and
construction process prior to continuing with a subsequent layer, or sealing, or opening to traffic, after moisture has left the system
through evaporation and/or drainage. This may also be referred to as the dried-back target strength.
3.2.3 heavy impact value (IV/H), n—the IV derived from using a 20 kg (44 lbm) mass hammer 130 mm (5 in.) in diameter free
falling 300 mm (12 in.).
3.2.4 heavy medium heavy impact value (IV/HMH), n—the IV derived from using a 10 kg (22 lbm) mass hammer 130 mm (5 in.)
in diameter free falling 300 mm (12 in).
3.2.5 impact soil tester, n—testing apparatus used to obtain an IV of a soil.
3.2.6 impact value (IV), n—the value expressed in units of tens of gravities (g) and reported to the nearest whole numberin whole
numbers derived from the peak deceleration of a 4.5 kg (10 lbm) instrumented compaction hammer 50 mm (2.0 in.) in diameter
free falling 450 mm (18 in.).
3.2.7 in-service target IV, n—the desired strength, in terms of IV, to be achieved in the field for a particular material and
construction process once the road is opened to traffic and has reached equilibrium. This may also be referred to as the in-service
target strength.
3.2.8 light impact value (IV/L), n—the IV derived from using a 0.5 kg (1.1 lbm) mass hammer 50 mm (2.0 in.) in diameter free
falling 300 mm (12 in.).
3.2.9 medium impact value (IV/M), n—the IV derived from using a 2.25 kg (5 lbm) mass hammer 50 mm (2.0 in) in diameter free
falling 450 mm (18 in.).
4. Summary of Test Method
4.1 The test apparatus is placed on the material to be tested either in a mold or on naturally occurring or compacted soil in the
field. The hammer is raised to a set height and allowed to free fall. The instrumentation of the test apparatus displays a value in
tens of gravities (g) of the peak deceleration of the hammer’s impact as recorded by an accelerometer fitted to the top of the
hammer body. A total of four blows of the hammer are applied on the same spot to determine the IV for each test performed.
4.2 A lighter hammer of Lighter hammers at 0.5 kg (1.1 lbm) or 2.25 kg (5 lbm) may be used for softer conditions or fragile
materials instead of the 4.5 kg (10 lbm) standard hammer to determine the IV. When used, the resulting value is termed the Light
Impact Value (IV/L) for the 0.5 kg (1.1 lbm) hammer or Medium Impact Value (IV/M) for the 2.25 kg (5 lbm) hammer.
4.3 A larger, heavier hammer ofLarger, heavier hammers at 10 kg (22 lbm) or 20 kg (44 lbm) may be used instead of the 4.5 kg
(10 lbm) standard hammer to determine the IV for harder conditions or to test through a larger zone both horizontally and vertically.
When used, the resulting value is termed the Heavy Medium Heavy Impact Value (IV/HMH) for the 10 kg (22 lbm) hammer or
Heavy Impact Value (IV/H) for the 20 kg (44 lbm) hammer.
5. Significance and Use
5.1 Impact Value, as determined using the standard 4.5 kg (10 lbm) hammer, has direct application to design and construction of
pavements and a general application to earthworks compaction control and evaluation of strength characteristics of a wide range
of materials, such as soils, soil aggregates, stabilized soil and recreational turf.aggregates and stabilized soil. Impact Value is one
of the properties used to evaluate the strength of a layer of soil up to about 150 mm (6 in.) in thickness using a 50 mm (2 in.)
diameter hammer or up to 380 mm (15 in.) in thickness using a 130 mm (5 in.) diameter hammer, and by inference to indicate
the compaction condition of this layer. Impact Value reflects and responds to changes in physical characteristics that influence
strength. It is a dynamic force penetration force-penetration property and may be used to set a strength parameter.
D5874 − 24
5.2 This test method provides immediate results in terms of IV and may be used for the process control of pavement or earthfill
activities where the avoidance of delays is important and where there is a need to determine variability when statistically based
quality assurance procedures are being used.
5.3 This test method does not provide results directly as a percentage of compaction but rather as a strength index value from
which compaction may be inferred for the particular moisture conditions. From observations, strength either remains constant
along the dry side of the compaction curve or else reaches a peak and and, for both cases, declines rapidly with increase in water
content beyond a point slightly dry of optimum water content. content, at approximately 0.5 percent. This is generally between 95
and 98 % maximum dry density (see Fig. 1 and Fig. 2). An as-compacted target strength in terms of IV may be designated from
laboratory testing or field trials as a strength to achieve in the field as the result of a compaction process for a desired density and
water content. If testing is performed after compaction when conditions are such that the water content has changed from the
critical value, determination of the actual water content by laboratory testing enables the field density to be inferred from regression
equations using IV, density and water content.
NOTE 2—Impact Value may be used as a means to improve the compaction process by giving instant feedback on roller efficiency, uniformity, confirming
the achievement of the target strength, and by inference the achieved density. When inferring density solely from IV, however, it should be is considered
as only indicative of density. Where strict acceptance on a density ratio basis is required, test methods that measure density directly shall be used.
5.4 This test method may be used to monitor strength changes during a compaction process or over time due to seasonal,
environmental or traffic changes.
NOTE 3—For in-place soil strength evaluation where there may be a dry and hard surface layer (crust), testing both the crust and the underlying layer
may be required.
FIG. 1 Illustration of Target IV for Material with No Peak
D5874 − 24
FIG. 2 Illustration of Target IV for Material with Pronounced Peak
5.5 The standard instrument is based on a 4.5 kg (10 lbm) compaction hammer using a 450 mm (18 in.) drop height. The hammer
has been is equipped with an accelerometer and instrumented using a peak hold electronic circuit to read the peak deceleration on
impact. The circuitry is filtered electronically to remove unwanted frequencies and the peak deceleration is displayed in units of
ten gravities (g) with the output below units of ten gravities truncated.
5.6 The peak deceleration on which IV is derived represents the area under the deceleration versus time curve which for most soils
may be assumed as half a sinusoid. Applying double integration provides first the time velocity time-velocity relationship and
second, the time penetration second the time-penetration relationship. As force is also directly related to deceleration, the IV
therefore,therefore represents both stress and penetration and may be taken as a direct measurement of stiffness or strength (see
Fig. 3).
5.7 Impact Value may be correlated with an unsoaked CBR.
5.8 Impact Value may be expressed as a hammer modulus, analogous with elastic modulus or deformation modulus.
5.9 The light hammer useslighter hammers use the same accelerometer and instrumentation as the standard hammer. The smaller
mass of Utilization of lighter masses at 0.5 kg (1.1 lbm) and 2.25 kg (5 lbm) results in more sensitivity for lower strength materials
compared to the standard mass; that is, the zero to 100 IV scale is expanded with thisthese lighter hammer massmasses and
provides more definition on softer materials. materials, along with there being less indentation into the material. To avoid
confusion, the IV of the light hammerlighter hammers is notated as IV/L.IV/L for the 0.5 kg (1.1 lbm) mass and as IV/M for the
2.25 kg (5 lbm) mass.
5.10 Light Impact Value has applications for recreation turf hardness evaluation, where the condition of the surface affects ball
D5874 − 24
FIG. 3 Development of Force-Penetration from Deceleration Versus Time
bounce characteristics, the performance or injury potential to participants, and where more sensitivity compared to the standard
hammer is required or an imprint left by the 4.5 kg (10 lbm) hammer or other test methods is undesirable, such as on a golf putting
green.
5.10 The medium hammer uses the same accelerometer and instrumentation as the standard hammer and provides a sensitivity
between that of the standard hammer and light hammer. The IV of the medium hammer is notated as IV/M.
5.11 The Light Impact Value and Medium Impact Value has application to sand and earthworks, and natural turfgrass and artificial
have application to testing of sand, peat and for natural and artificial recreation turf hardness evaluation, the last primarily in
relation to where it is that the hardness of recreation turf surfaces affects ball bounce characteristics and the performance or injury
potential to the participants, and participants. Medium Impact Value is preferable over the Light Impact Value in relation to
assessing natural turf where there is thicker thatch and longer grass for such application.whereas Light Impact Value is preferable
for finely mown grass surfaces where less indentation than that of the medium hammer is desired, such as testing of grass tennis
courts and golf putting greens.
5.12 The medium hammer has application to testing of earthworks materials.
5.13 The heavy medium heavy hammer uses the same accelerometer and instrumentation as the standard hammer,hammer and
tests through a larger zone both horizontally and vertically than the lighter impact soil testers because of its larger diameter mass.
The IV of the heavy medium heavy hammer is notated as IV/HMH.
D5874 − 24
5.14 The Heavy Medium Heavy Impact Value has application to testing the same materials as those tested by the standard, light
and medium impact soil testers, for evaluation of a layer of soil up to about 380 mm.light, medium and heavy impact soil testers.
5.15 The heavy hammer uses the same accelerometer and instrumentation as the standard hammer,hammer and tests through a
larger zone both horizontally and vertically. vertically as compared to the 50 mm (2 in.) diameter impact soil testers. The IV of
the heavy hammer is notated as IV/H.
5.16 The Heavy Impact Value has application to testing the same materials as those tested by the standard, light, medium, and
heavy medium heavy impact soil testers,testers but the greater mass of this impact soil tester provides less sensitivity of the output
so is applicable for harder materials at the top end the scales or beyond the ranges of the lighter impact soil testers. The larger
diameter mass of the heavy impact soil tester tests through a larger zone both horizontally and vertically than the smaller diameter
impact soil testers.
NOTE 4—The quality of the results produced by this test method is dependent on the competence of the personnel performing it and the suitability of the
equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing. Users
of this test method are cautioned that compliance with Practice D3740 does not in itself ensure reliable results. Reliable results depend on many factors;
Practice D3740 provides a means of evaluating some of those factors.
6. Interferences
6.1 Due to the laws of physics and soil mechanics, a significant change in the output occurs as a result of a significant change in
the mass and/or diameter and/or drop height and/or design and/or construction of an impact soil tester. Therefore, where there is
a significant change in any of the above parameters between impact soil testers, the output of one cannot be taken as one-for-one
with the output of another. A significant change in any of these parameters however allows for the Impact Value concept to be
extended to a greater number of situations and applications while utilizing the same instrumentation. The different signifiers for
the Impact Value output as given herein not only help to avoid confusion but provide a shorthand means to identify the output of
an impact soil tester according to the particular mass and diameter of hammer and its standard drop height.
6.2 The maximum of the first four blows has been found through experiment and practice to be the simplest means by which to
obtain consistent results. Analysis of the blow count has shown that the first blow or two may be considered as a seating procedure
as they create a compacted wedge or hemisphere of soil that is subsequently forced into the body of the soil causing an increase
in deceleration, that is, an increase in IV, as successive blows are applied. In general, deceleration remains practically unchanged
after the third or fourth blow with additional blows continuing to produce a constant amount of penetration. If lower values occur
with subsequent blows, this is due apparently to the hammer striking the sides of the indentation or by loose material falling onto
the strike surface causing a bias in this direction.
7. Apparatus
7.1 Impact Soil Tester—A test apparatus consisting of a hammer, guide tube,tube and electronic instrumentation. Detailed
information on the apparatus is contained in Annex A1. A typical configuration is shownfor a 50 mm (2 in.) diameter hammer that
utilizes a tubular handle is illustrated in Fig. 4.
7.2 Mold—A 152.4 6 0.7 mm (6.000 6 0.026 in.) diameter mold conforming to the requirements of Test Methods D698
Procedure C, D1557 Procedure C,C or D1883 with a spacer disc.disk.
7.2.1 Molds of other, typically larger, dimensions or that of D1883 without a spacer disk may be used but must such shall be
reported accordingly in the report.
NOTE 5—For a particular material, the smaller 101.6 mm (4 in.) mold of Test Method D698 may be used if it has been proven by a laboratory test
comparison with the 152.4 mm (6 in.) mold of Test Method D1557 that there is no significant difference in the IV results. Mold dimensions are to be
consistent with Test Methods D698 and D1557.
8. Procedure
8.1 Operational Verification Checks—Perform operational verification checks at the commencement of any testing program, after
repair, or repair or fresh calibration, or when the instrument is suspect using the operational check ring as follows.
D5874 − 24
FIG. 4 Illustration (Cross Section) of the Standard 4.5 kg Impact Soil Tester with Hammer at Rest in the Guide Tube
8.1.1 Place the ring on a dry, grease free smoothfree, smooth, hard surface of a solid massive object, such as a concrete floor over
ground. Place the guide tube centrally over the ring and drop the hammer five times from the set height mark as described in A2.1.3
for the standard 4.5 kg hammer or (10 lbm) hammer, A2.1.4 for the light 0.5 kg (1.1 lbm) hammer, A2.1.5 for the medium 2.25
kg (5 lbm) hammer or A2.1.6 for the heavy medium heavy 10 kg (22 lbm) hammer and 20 kg (44 lbm) heavy hammer. Operate
the instrumentation so as to obtain five separate readings. If this operational check procedure gives significantly different values
than shown on the ring, examine the dryness, cleanliness, smoothness and firmness of the support for the ring and the ring itself
and itself, check the external signal cable for damage in relation to open circuiting or short circuiting or poor connection(s), review
the operational check procedure and rerun the check at the same or another location. If the ring value is not satisfactorily
achievable, an electronic check may be carried out according to the manufacturer’s calibration instruction for the accelerometer-
.consult the manufacturer.
NOTE 6—To avoid the possibility of damage to the electronics or the hammer, it is recommended that the impact soil tester shouldis not be used directly
on hard surfaces such as concrete or otherwise in such a way on materials that it would give results of more than 100 IV (1000 g).
NOTE 7—The impact energy provided by the 4.5 kg hammer can cause undesired damage to surfaces and an impact soil test hammer with a mass greater
than 0.5 kg can cause damage to materials such as brick or concrete paving slabs or smoothly prepared turf surfaces.hard turf surfaces such as grass tennis
courts or golf putting greens.
8.2 Determine an IV as follows:
8.2.1 The peak deceleration that is the highest of the four successive blows is taken as the IV. The maximum of the first four blows
has been found through experiment and practice to be the simplest means by which to obtain consistent results. Analysis of the
blow count has shown that the first blow or two may be considered as seating procedure as they create a compacted wedge or
hemisphere of soil that is subsequently forced into the body of the soil causing an increase in deceleration, that is, an increase in
IV, as successive blows are applied. In general, deceleration remains practically unchanged after the third or fourth blow with
additional blows continuing to produce a constant amount of penetration. If lower values occur with subsequent blows, this is due
D5874 − 24
apparently to the hammer striking the sides of the indentation or by loose material falling onto the strike surface causing a bias
in this direction.on a test spot is taken as the IV.
8.2.2 Impact Values obtained from other blow counts, or an average thereof, shall be reported accordingly in the report.
8.3 Field Procedure A—If necessary, prepare the surface of the compacted or natural soil to be tested by lightly scuffing with the
foot to remove loose surface material. Before beginning a test,test ensure that the hammer strike face is clean of any soil or foreign
material build-up and that the guide tube is reasonably clean so as not to restrict a free fall. Place the impact soil tester in position
with the guide tube base set on the ground. Steady the guide tube to hold vertical in place, activate the instrumentation,
instrumentation and apply four free falling blows in succession from the set height of drop. Take and record the The highest value
of the four blows is taken as the IV.
NOTE 8—A method Methods of securing the guide tube in a vertical position is for the operator to place include placing a foot on the guide tube base
and steadysteadying the guide tube with the lower leg or knee, or both. Raising of the hammer is done by the knee, or by using a spare hand instead of
placing a foot on the base if the design allows. It is suggested if securing the base with a foot to use the hand on the same side of the body as the foot
securing the guide tube.for raising the hammer.
NOTE 9—For sloping sites, a level test surface may need to be prepared so that the guide tube base rests on the surface with the guide tube as near to
vertical as possible.
8.4 Field Procedure B—Follow Field Procedure A but determine the water content of the material at a location 100 mm (4 in.)
to 150 mm (6 in.) from the edge of the guide tube flange content. flange. Determine the water content according to the applicable
test methods listed in 2.1.
8.5 Field Procedure C—Follow Field Procedure B but determine also the density of the material a
...