ASTM D7380/D7380M-21

Standard Test Method for Soil Compaction Determination at Shallow Depths Using 2.3-kg [5-lbm] Dynamic Cone Penetrometer

SIGNIFICANCE AND USE
5.1 The test method is used to assess the compaction effort of compacted materials. The number of drops required to drive the cone a distance of 83 mm [3.25 in.] is used as a criterion to determine the pass or fail in terms of soil percent compaction.  
5.2 The device does not measure soil compaction directly and requires determining the correlation between the number of drops and percent compaction in similar soil of known percent compaction and water content.  
5.3 The number of drops is dependent on the soil water content. Calibration of the device should be performed at a water content equal to the water content expected in the field.  
5.4 There are other DCPs with different dimensions, hammer weights, cone sizes, and cone geometries. Different test methods exist for these devices (such as D6951) and the correlations of the 5-lbm DCP with soil percent compaction are unique to this device.  
5.5 The 5-lbm DCP is a simple device, capable of being handled and operated by a single operator in field conditions. It is typically used as Quality Control (QC) of layer-by-layer compaction by construction crew in roadway pavement, backfill compaction in confined cuts and trenches, and utility pavement restoration work.
Note 1: The quality of 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/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of these factors.
SCOPE
1.1 This test method covers the procedure for the determination of the number of drops required for a dynamic cone penetrometer with a 2.3-kg [5-lbm] drop hammer falling 508 mm [20 in.] to penetrate a certain depth in compacted backfill.  
1.2 The device is used in the compaction verification of fine- and coarse-grained soils, granular materials, and weak stabilized or modified material used in subgrade, base layers, and backfill compaction in confined cuts and trenches at shallow depth.  
1.3 The test method is not applicable to highly stabilized and cemented materials or granular materials containing a large percentage of aggregates greater than 37 mm [1.5 in.].  
1.4 The method is dependent upon knowing the field water content and the user having performed calibration tests to determine cone penetration resistance of various compaction levels and water contents.  
1.5 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. Within the text of this standard, SI units appear first followed by the inch-pound [or other non-SI] units in brackets. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard.  
1.6 It is common practice in the engineering profession to concurrently use pounds to represent both a unit of mass [lbm] and a force [lbf]. This implicitly combines two separate systems of units; that is, the absolute system and the gravitational system. This standard has been written using the absolute system of units when dealing with the inch-pound system. In this system, the pound [lbf] represents a unit of force (weight). However, the use of balances or scales recording pounds of mass [lbm] or the reading of density in lbm/ft3 shall not be regarded as a nonconformance with this standard.  
1.7 All observed and calculated values shall conform to the guidelines for significant digits and rounding...

General Information

• Status: Published
• Publication Date: 31-Oct-2021
• ICS: 13.080.20 - Physical properties of soils
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: D18 - Soil and Rock
• Drafting Committee: D18.08 - Special and Construction Control Tests

Relations

• Refers: ASTM D4959-24 - Standard Test Method for Determination of Water Content of Soil By Direct Heating
• Effective Date: 01-Feb-2024
• Refers: ASTM D3740-23 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Nov-2023
• Refers: ASTM D3740-19 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Oct-2019
• Refers: ASTM D2216-19 - Standard Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass
• Effective Date: 01-Mar-2019
• Refers: ASTM D6938-17 - Standard Test Methods for In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth)
• Effective Date: 01-Mar-2017
• Refers: ASTM D4959-16 - Standard Test Method for Determination of Water Content of Soil By Direct Heating
• Effective Date: 01-Jan-2016
• Refers: ASTM D6938-15 - Standard Test Methods for In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth)
• Effective Date: 01-Aug-2015
• Refers: ASTM D653-14 - Standard Terminology Relating to Soil, Rock, and Contained Fluids
• Effective Date: 01-Aug-2014
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM D3740-12a - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-May-2012
• Refers: ASTM D698-12 - Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12 400 ft-lbf/ft³ (600 kN-m/m³))
• Effective Date: 01-May-2012
• Refers: ASTM D698-12e1 - Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12 400 ft-lbf/ft³ (600 kN-m/m³))
• Effective Date: 01-May-2012
• Refers: ASTM D1557-12 - Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft³ (2,700 kN-m/m³))
• Effective Date: 01-May-2012
• Refers: ASTM D3740-12 - Standard Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction
• Effective Date: 01-Mar-2012
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011

Overview

ASTM D7380/D7380M-21 is a standard test method developed by ASTM International for determining soil compaction at shallow depths using a 2.3-kg [5-lbm] dynamic cone penetrometer (DCP). This test method is widely used in civil engineering and construction projects to verify the compaction quality of fine- and coarse-grained soils, granular materials, and weakly stabilized or modified soils in subgrade, base layers, and backfill for roadways, trenches, and utility restorations. Rather than directly measuring compaction, this method determines the number of drops needed to drive a standard cone a specified distance (83 mm [3.25 in.]), which is then correlated to the soil percent compaction through prior calibration in soils of similar properties and moisture content.

Key Topics

• Purpose and Significance

  • The DCP method is crucial for assessing whether the required compaction levels in construction materials have been achieved, supporting quality control (QC) procedures in the field.
  • The result is determined by counting the number of hammer drops needed to advance the cone a fixed distance, serving as a pass/fail criterion for soil compaction.

• Calibration and Water Content

  • Accurate results require calibration of the DCP against soils of the same type and water content as those found on-site.
  • The correlation between drop count and compaction percentage varies based on soil properties and water content.

• Device Characteristics

  • The standard applies to a DCP with a 2.3-kg [5-lbm] drop hammer and specific geometry.
  • Other DCP devices exist (e.g., ASTM D6951), but the drop count-to-compaction relationship is unique to the device specified in ASTM D7380/D7380M-21.

• Practical Operation

  • The 5-lbm DCP is designed for single-operator usage under typical field conditions.
  • It is simple, portable, and suitable for both surface and confined space testing via extension rods.

Applications

• Roadway and Pavement Construction

  • Provides real-time quality control of compaction on each lift of soil or granular base, ensuring durable roads.

• Trench Backfill and Utility Restoration

  • Commonly used to monitor compaction of backfill in narrow trenches, confined cuts, and beneath utility pavement repairs, especially in urban infrastructure projects.

• Construction Quality Assurance

  • Enables crews and inspectors to rapidly verify layer compaction meets project specifications, minimizing project delays and potential failures due to inadequate compaction.

• Limitations

  • Not suitable for highly stabilized, cemented materials or soils with a significant proportion of aggregates larger than 37 mm [1.5 in.].
  • Reliable results require correct calibration and accurate field water content measurements.

Related Standards

• ASTM D653 - Terminology Relating to Soil, Rock, and Contained Fluids.
• ASTM D698 - Laboratory Compaction Characteristics of Soil Using Standard Effort.
• ASTM D1556/D6938 - Methods for In-Place Density and Water Content of Soil.
• ASTM D2216 - Laboratory Determination of Water Content of Soil.
• ASTM D6951 - Use of the Dynamic Cone Penetrometer for other device specifications.
• ASTM D3740 - Minimum Requirements for Agencies Engaged in Soil Testing/Inspection.

Practical Value

Using ASTM D7380/D7380M-21 helps ensure that soil and backfill compaction meets project requirements for stability and longevity. The standard offers a straightforward, repeatable process for on-site testing, reducing ambiguity in construction QC. Proper use, calibration, and adherence to the standard contribute to safer, more efficient work sites and improved infrastructure performance.

Keywords: ASTM D7380, soil compaction, dynamic cone penetrometer, DCP test, shallow depth, field density, construction quality control, backfill verification, pavement restoration, soil compaction standard.

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: D7380/D7380M − 21
Standard Test Method for
Soil Compaction Determination at Shallow Depths Using
2.3-kg [5-lbm] Dynamic Cone Penetrometer
This standard is issued under the fixed designation D7380/D7380M; 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* system.Inthissystem,thepound[lbf]representsaunitofforce
(weight). However, the use of balances or scales recording
1.1 This test method covers the procedure for the determi-
pounds of mass [lbm] or the reading of density in lbm/ft shall
nation of the number of drops required for a dynamic cone
not be regarded as a nonconformance with this standard.
penetrometer with a 2.3-kg [5-lbm] drop hammer falling
508 mm [20 in.] to penetrate a certain depth in compacted 1.7 All observed and calculated values shall conform to the
backfill. guidelines for significant digits and rounding established in
Practice D6026.
1.2 The device is used in the compaction verification of
1.8 This standard does not purport to address all of the
fine- and coarse-grained soils, granular materials, and weak
safety concerns, if any, associated with its use. It is the
stabilized or modified material used in subgrade, base layers,
responsibility of the user of this standard to establish appro-
and backfill compaction in confined cuts and trenches at
priate safety, health, and environmental practices and deter-
shallow depth.
mine the applicability of regulatory limitations prior to use.
1.3 The test method is not applicable to highly stabilized
1.9 This international standard was developed in accor-
andcementedmaterialsorgranularmaterialscontainingalarge
dance with internationally recognized principles on standard-
percentage of aggregates greater than 37 mm [1.5 in.].
ization established in the Decision on Principles for the
1.4 The method is dependent upon knowing the field water
Development of International Standards, Guides and Recom-
content and the user having performed calibration tests to
mendations issued by the World Trade Organization Technical
determine cone penetration resistance of various compaction
Barriers to Trade (TBT) Committee.
levels and water contents.
2. Referenced Documents
1.5 Units—The values stated in either SI units or inch-
pound units are to be regarded separately as standard. The
2.1 ASTM Standards:
values stated in each system are not necessarily exact equiva-
D653 Terminology Relating to Soil, Rock, and Contained
lents; therefore, to ensure conformance with the standard, each
Fluids
system shall be used independently of the other, and values
D698 Test Methods for Laboratory Compaction Character-
from the two systems shall not be combined.Within the text of istics of Soil Using Standard Effort (12,400 ft-lbf/ft (600
this standard, SI units appear first followed by the inch-pound
kN-m/m ))
[or other non-SI] units in brackets. Reporting of test results in D1556 Test Method for Density and Unit Weight of Soil in
units other than SI shall not be regarded as nonconformance
Place by Sand-Cone Method
with this standard. D1557 Test Methods for Laboratory Compaction Character-
istics of Soil Using Modified Effort (56,000 ft-lbf/ft
1.6 It is common practice in the engineering profession to
(2,700 kN-m/m ))
concurrently use pounds to represent both a unit of mass [lbm]
D2216 Test Methods for Laboratory Determination of Water
and a force [lbf]. This implicitly combines two separate
(Moisture) Content of Soil and Rock by Mass
systems of units; that is, the absolute system and the gravita-
D3740 Practice for Minimum Requirements for Agencies
tional system. This standard has been written using the
Engaged in Testing and/or Inspection of Soil and Rock as
absolute system of units when dealing with the inch-pound
Used in Engineering Design and Construction
D4959 Test Method for Determination of Water Content of
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
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 Nov. 1, 2021. Published November 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2008. Last previous edition approved in 2015 as D7380 - 15. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D7380_D7380M-21. 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
D7380/D7380M − 21
Soil By Direct Heating needed to penetrate a certain distance between two marks on
D6026 Practice for Using Significant Digits and Data Re- the driving rod is used to determine soil compaction effort.
cords in Geotechnical Data
3.2.2 extension rod—in dynamic cone penetrometer, an
D6938 TestMethodsforIn-PlaceDensityandWaterContent
optional extension of the driving rod to allow the use of the
of Soil and Soil-Aggregate by Nuclear Methods (Shallow
5-lbm DCP in deep confined holes.
Depth)
3.2.2.1 Discussion—The extension rod has a sliding sleeve
D6951 TestMethodforUseoftheDynamicConePenetrom-
with two markers similar to the ones on the 5-lbm DCPdriving
eter in Shallow Pavement Applications
rod for identifying the penetration distance and allowing the
E691 Practice for Conducting an Interlaboratory Study to
readings to be taken near or at the surface of the hole.
Determine the Precision of a Test Method
4. Summary of Test Method
3. Terminology
4.1 The 5-lbm DCP is placed vertically and the drop
3.1 Definitions—For definitions of common technical terms
hammerisusedtopenetratethesoiluntilthelowermarkonthe
used in this standard, refer to Terminology D653.
driving rod is leveled with the surface of the soil.
3.2 Definitions of Terms Specific to This Standard:
4.2 The operator lifts the drop hammer to the upper stop
3.2.1 5-lbm dynamic cone penetrometer (5-lbm DCP)—
disk and releases it, allowing it to fall freely under gravity and
(Fig. 1) a device that uses a 2.3-kg [5-lbm] hammer to
strike an anvil, causing the cone to be driven into the soil. The
penetrate a cone tip inside the soil where the number of drops
numberofdropsneededtopenetratetheconeadistance83mm
[3.25 in.] from the lower mark on the driving rod to the upper
one is counted.
4.3 Thenumberofdropsisusedtodeterminethepassorfail
of soil compaction based on the results of calibration tests
between the number of drops and soil percent compaction in
similar soil of known percent compaction and water content.
5. Significance and Use
5.1 The test method is used to assess the compaction effort
of compacted materials. The number of drops required to drive
the cone a distance of 83 mm [3.25 in.] is used as a criterion to
determine the pass or fail in terms of soil percent compaction.
5.2 The device does not measure soil compaction directly
and requires determining the correlation between the number
of drops and percent compaction in similar soil of known
percent compaction and water content.
5.3 The number of drops is dependent on the soil water
content. Calibration of the device should be performed at a
water content equal to the water content expected in the field.
5.4 There are other DCPs with different dimensions, ham-
mer weights, cone sizes, and cone geometries. Different test
methods exist for these devices (such as D6951) and the
correlationsofthe5-lbmDCPwithsoilpercentcompactionare
unique to this device.
5.5 The 5-lbm DCP is a simple device, capable of being
handled and operated by a single operator in field conditions. It
is typically used as Quality Control (QC) of layer-by-layer
compaction by construction crew in roadway pavement, back-
fill compaction in confined cuts and trenches, and utility
pavement restoration work.
NOTE 1—The quality of 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/sampling/inspection/etc. Users of this standard are
cautioned that compliance with Practice D3740 does not in itself assure
reliable results. Reliable results depend on many factors; Practice D3740
FIG. 1 Schematic Diagram of the 5-lbm DCP Device provides a means of evaluating some of these factors.
D7380/D7380M − 21
6. Apparatus 6.8 The optional automated data readout unit should not
interfere with the operation and results of the device. The
6.1 Aschematic diagram of the 5-lbm DCPis shown in Fig.
output data of the system should satisfy the requirements of
3 1
1. The device consists of an 19 6 1.6 mm [ ⁄4 6 ⁄16 in.] steel
data reporting in Section 9.
rod with a 2.3 6 0.1 kg [5 6 0.2 lbm] drop hammer. The
hammer drops a distance 508 6 10 mm [20 6 0.4 in.] between
7. Calibration
the upper stop plate and the anvil.
7.1 Device preparation—The device shall be inspected for
6.2 Driving Rod—Thedrivingrodhastwopermanentmarks
damaged parts before testing; the cone tip angle should not be
orgrovestomonitorconepenetrationdepth.Thelowermarkis
damaged and be within the acceptable tolerance before testing.
at a distance 83 mm [3.25 in.] from the top surface of the cone
and the distance between the two marks is 83 mm [3.25 in.].
7.2 Soil sample preparation:
6.3 Cone Tip—A replaceable cone tip of hardened steel or 7.2.1 The soil percent compaction and optimum water
content are determined for soil samples obtained from the field
similar material with angle 25 6 2 degrees is placed at the
according to Test Method D698 or D1557 for laboratory
bottom of the driving rod. Fig. 2 shows the dimensions of the
cone tip. compactioncharacteristicsofsoilaspertheprojectcompaction
specifications.
6.4 Extension Rod—An extension rod may be used to
7.2.2 A soil sample is obtained from the field to fill a 610
monitor compaction in deep cuts and narrow trenches where
mm [2 ft] wide by 610 mm [2 ft] long test pit with a depth of
the operator has to work from the ground surface. The
305 mm [12 in.]. The test pit can be constructed in the site or
extension rod should be of the same diameter and material as
in the lab.
thedrivingrod.Fig.3showsaschematicofthedevicewiththe
7.2.3 The soil is placed in the pit within 62 % of its
extension rod used in a confined hole.
optimum water content or as specified in the project compac-
6.5 When the device is used in small holes and trenches, a
tion specifications. The soil water content in the pit is deter-
sleeve is used to monitor the penetration distance from the
mined using Test Method D2216 or D6938.
surface as shown in Fig. 3. The lower mark on the sleeve is
7.2.4 Thesoiliscompactedintwolifts,150mm[6in.]each
leveled with the ground surface using a straight edge and the
using equal compaction effort in each lift. Initially, the soil is
sleeveistightenedbyascrewtopreventitfrommovingduring
compacted using a low compaction effort. The soil density is
the test. Fig. 4 shows the dimensions of the sleeve.
measured using Test Method D6938 or D1556.
6.6 The addition of extensions will change the mass of the
7.3 Setup of the cone—The operator holds the device
device and the energy delivered to the cone. When extension
vertically by the handle over the soil surface then lifts the drop
rodsandsleevesareused,calibrationtestsshouldbeperformed
hammer and releases it to cause the cone to penetrate until the
with these extensions attached to the device.
lower mark on the driving rod is leveled with the surface of the
6.7 An automated electronic data readout unit may be used
soil layer.
to register the number of drops and the penetrating distance.
7.4 Cone testing—The operator lifts the drop hammer to the
The system should give a signal and stop counting the number
upper stop disk and releases it, allowing it to fall freely under
of drops once the penetration equals the distance from the
gravity. The hammer shall not unduly impact the upper disk
lower mark to the top one.
when raised. The operator repeats the process and the number
of drops needed to advance the cone a distance 83 mm
[3.25 in.] is recorded.
NOTE 2—In stiff soils, where the number of drops between the marks
exceeds 20 drops at low compaction, the setup of the DCP test can be
performed by dropping the hammer until only the top surface of cone
(instead of the lower mark) is leveled with the surface of the soil. The
testing is then performed by counting the number of drops for the distance
of 83 mm [3.25 in.] between the top surface of the cone and the lower
mark as shown in Fig. 1. Record the starting point of testing in the report.
7.5 If the last drop needed to advance the cone 83 mm [3.25
in.]overshootsthemark,thenthelastdropisnotcountedinthe
total number of drops.
7.6 The soil is removed from the test pit, replaced, and
compacted using higher compaction efforts at the same water
content. Steps 7.3 to 7.7 are repeated at higher compaction
efforts until the compaction exceeds the specified percent
compaction required in the field.
7.7 The number of hammer drops at each soil density is
plotted against the corresponding soil percent compaction as
FIG. 2 Dimensions of the Cone Tip shown in Fig. 5. A minimum of four points should be used to
D7380/D7380M − 21
FIG. 3 Schematic of the 5-lbm DCP with Extension Rod in Con-
fined Excavation
establish the calibration curve. At least one point should be
within2 %ofthemaximumpercentcompactionrequiredinthe
field.
NOTE 3—Calibration of the devic
...

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: D7380 − 15 D7380/D7380M − 21
Standard Test Method for
Soil Compaction Determination at Shallow Depths Using
5-lb (2.3 kg) 2.3-kg [5-lbm] Dynamic Cone Penetrometer
This standard is issued under the fixed designation D7380;D7380/D7380M; 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 procedure for the determination of the number of drops required for a dynamic cone penetrometer
with a 5-lb (2.3-kg)2.3-kg [5-lbm] drop hammer falling 20 in. (508 mm) 508 mm [20 in.] to penetrate a certain depth in compacted
backfill.
1.2 The device is used in the compaction verification of fine- and coarse-grained soils, granular materials, and weak stabilized or
modified material used in subgrade, base layers, and backfill compaction in confined cuts and trenches at shallow depth.
1.3 The test method is not applicable to highly stabilized and cemented materials or granular materials containing a large
percentage of aggregates greater than 1.5 in. (37 mm).37 mm [1.5 in.].
1.4 The method is dependent upon knowing the field water content and the user having performed calibration tests to determine
cone penetration resistance of various compaction levels and water contents.
1.5 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values
givenstated in parentheses are mathematical conversions to SI units that are provided for information only and are not considered
each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined. Within the text of this standard, SI units appear
first followed by the inch-pound [or other non-SI] units in brackets. Reporting of test results in units other than SI shall not be
regarded as nonconformance with this standard.
1.6 It is common practice in the engineering profession to concurrently use pounds to represent both a unit of mass (lbm)[lbm]
and a force (lbf).[lbf]. This implicitly combines two separate systems of units; that is, the absolute system and the gravitational
system. This standard has been written using the gravitationalabsolute system of units when dealing with the inch-pound system.
In this system, the pound (lbf)[lbf] represents a unit of force (weight). However, the use of balances or scales recording pounds
of mass (lbm)[lbm] or the reading of density in lbm/ft shall not be regarded as a nonconformance with this standard.
1.7 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026.
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 Nov. 1, 2015Nov. 1, 2021. Published November 2015November 2021. Originally approved in 2008. Last previous edition approved in 20082015
as D7380 - 08.D7380 - 15. DOI: 10.1520/D7380-15.10.1520/D7380_D7380M-21.
*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
D7380/D7380M − 21
1.8 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.9 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 ))
D1556 Test Method for Density and Unit Weight of Soil in Place by Sand-Cone Method
D1557 Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft (2,700
kN-m/m ))
D2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass
D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in
Engineering Design and Construction
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)
D6951 Test Method for Use of the Dynamic Cone Penetrometer in Shallow Pavement Applications
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions—For definitions of common technical terms used in this standard, refer to Terminology D653.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 5-lb5-lbm dynamic cone penetrometer (5-lb(5-lbm DCP)—(Fig. 1) a device that uses a 5-lb (2.3-kg)2.3-kg [5-lbm] hammer
to penetrate a cone tip inside the soil where the number of drops needed to penetrate a certain distance between two marks on the
driving rod is used to determine soil compaction effort.
3.2.2 extension rod—in dynamic cone penetrometer, an optional extension of the driving rod to allow the use of the 5-lb5-lbm DCP
in deep confined holes.
3.2.2.1 Discussion—
The extension rod has a sliding sleeve with two markers similar to the ones on the 5-lb5-lbm DCP driving rod for identifying the
penetration distance and allowing the readings to be taken near or at the surface of the hole.
3.2.3 electronic readout unit—in dynamic cone penetrometer, optional readout device to automatically count the number of
hammer drops and penetration distance inside the soil.
4. Summary of Test Method
4.1 The 5-lb5-lbm DCP is placed vertically and the drop hammer is used to penetrate the soil until the lower mark on the driving
rod is leveled with the surface of the soil.
4.2 The operator lifts the drop hammer to the upper stop disk and releases it, allowing it to fall freely under gravity and strike an
anvil, causing the cone to be driven into the soil. The number of drops needed to penetrate the cone a distance 3.25 in. (83 mm)83
mm [3.25 in.] from the lower mark on the driving rod to the upper one is counted.
4.3 The number of drops is used to determine the pass or fail of soil compaction based on the results of calibration tests between
the number of drops and soil percent compaction in similar soil of known percent compaction and water content.
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.
D7380/D7380M − 21
FIG. 1 Schematic Diagram of the 5-lb5-lbm DCP Device
5. Significance and Use
5.1 The test method is used to assess the compaction effort of compacted materials. The number of drops required to drive the
cone a distance of 3.25 in. (83 mm)83 mm [3.25 in.] is used as a criterion to determine the pass or fail in terms of soil percent
compaction.
5.2 The device does not measure soil compaction directly and requires determining the correlation between the number of drops
and percent compaction in similar soil of known percent compaction and water content.
5.3 The number of drops is dependent on the soil water content. Calibration of the device should be performed at a water content
equal to the water content expected in the field.
5.4 There are other DCPs with different dimensions, hammer weights, cone sizes, and cone geometries. Different test methods
exist for these devices (such as D6951) and the correlations of the 5-lb5-lbm DCP with soil percent compaction are unique to this
device.
5.5 The 5-lb5-lbm DCP is a simple device, capable of being handled and operated by a single operator in field conditions. It is
D7380/D7380M − 21
typically used as Quality Control (QC) of layer-by-layer compaction by construction crew in roadway pavement, backfill
compaction in confined cuts and trenches, and utility pavement restoration work.
NOTE 1—The quality of 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/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable
results depend on many factors; Practice D3740 provides a means of evaluating some of these factors.
6. Apparatus
11 3 1
6.1 A schematic diagram of the 5-lb5-lbm DCP is shown in Fig. 1. The device consists of an ⁄16 6 19 6 1.6 mm [ ⁄4 6 ⁄16 in.
(17.5 6 1.6 mm) in.] steel rod with a 5 6 0.2 lb (2.3 6 0.1 kg) 2.3 6 0.1 kg [5 6 0.2 lbm] drop hammer. The hammer drops a
distance 20 6 0.4 in. (508 6 10 mm)508 6 10 mm [20 6 0.4 in.] between the upper stop plate and the anvil.
6.2 Driving Rod—The driving rod has two permanent marks or groves to monitor cone penetration depth. The lower mark is at
a distance 383 ⁄4 in. (83 mm) mm [3.25 in.] from the top surface of the cone and the distance between the two marks is 3.25 in.
(83 mm).83 mm [3.25 in.].
6.3 Cone Tip—A replaceable cone tip of hardened steel or similar material with angle 25 6 2 degrees is placed at the bottom of
the driving rod. Fig. 2 shows the dimensions of the cone tip.
6.4 Extension Rod—An extension rod may be used to monitor compaction in deep cuts and narrow trenches where the operator
has to work from the ground surface. The extension rod should be of the same diameter and material as the driving rod. Fig. 3
shows a schematic of the device with the extension rod used in a confined hole.
6.5 When the device is used in small holes and trenches, a sleeve is used to monitor the penetration distance from the surface as
shown in Fig. 3. The lower mark on the sleeve is leveled with the ground surface using a straight edge and the sleeve is tightened
by a screw to prevent it from moving during the test. Fig. 4 shows the dimensions of the sleeve.
6.6 The addition of extensions will change the mass of the device and the energy delivered to the cone. When extension rods and
sleeves are used, calibration tests should be performed with these extensions attached to the device.
6.7 An automated electronic data readout unit may be used to register the number of drops and the penetrating distance. The
system should give a signal and stop counting the number of drops once the penetration equals the distance from the lower mark
to the top one.
FIG. 2 Dimensions of the Cone Tip
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FIG. 3 Schematic of the 5-lb5-lbm DCP with Extension Rod in
Confined Excavation
FIG. 4 Detail of the Sleeve Used with Extension Rod
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6.8 The optional automated data readout unit should not interfere with the operation and results of the device. The output data of
the system should satisfy the requirements of data reporting in Section 9.
7. Calibration
7.1 Device preparation—The device shall be inspected for damaged parts before testing; the cone tip angle should not be damaged
and be within the acceptable tolerance before testing.
7.2 Soil sample preparation:
7.2.1 The soil percent compaction and optimum water content are determined for soil samples obtained from the field according
to Test Method D698 or D1557 for laboratory compaction characteristics of soil as per the project compaction specifications.
7.2.2 A soil sample is obtained from the field to fill a 2 ft (610 mm) wide by 2 ft 610 mm [2 ft] wide by 610 mm [2 ft] long test
pit with a depth of 12 in. (305 mm). 305 mm [12 in.]. The test pit can be constructed in the site or in the lab.
7.2.3 The soil is placed in the pit within 62 % of its optimum water content or as specified in the project compaction
specifications. The soil water content in the pit is determined using Test Method D2216 or D6938.
7.2.4 The soil is compacted in two lifts, 6 in. (150 mm)150 mm [6 in.] each using equal compaction effort in each lift. Initially,
the soil is compacted using a low compaction effort. The soil density is measured using Test Method D6938 or D1556.
7.3 Setup of the cone—The operator holds the device vertically by the handle over the soil surface then lifts the drop hammer and
releases it to cause the cone to penetrate until the lower mark on the driving rod is leveled with the surface of the soil layer.
7.4 Cone testing—The operator lifts the drop hammer to the upper stop disk and releases it, allowing it to fall freely under gravity.
The hammer shall not unduly impact the upper disk when raised. The operator repeats the process and the number of drops needed
to advance the cone a distance 3.25 in. (83 mm) 83 mm [3.25 in.] is recorded.
NOTE 2—In stiff soils, where the number of drops between the marks exceeds 20 drops at low compaction, the setup of the DCP test can be performed
by dropping the hammer until only the top surface of cone (instead of the lower mark) is leveled with the surface of the soil. The testing is then performed
by counting the number of drops for the distance of 3.25 in. (83 mm)83 mm [3.25 in.] between the top surface of the cone and the lower mark as shown
in Fig. 1. Record the starting point of testing in the report.
7.5 If the last drop needed to advance the cone 3.25 in. (83 mm)83 mm [3.25 in.] overshoots the mark, then the last drop is not
counted in the total number of drops.
7.6 The soil is removed from the test pit, replaced, and compacted using higher compaction efforts at the same water content. Steps
7.3 to 7.7 are repeated at higher compaction efforts until the compaction exceeds the specified percent compaction required in the
field.
7.7 The number of hammer drops at each soil density is plotted against the corresponding soil percent compaction as shown in
Fig. 5. A minimum of four points should be
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