ASTM D6958 - 20

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Designation: D6958 −20

Standard Test Methods for

Evaluating Side-Bonding Potential of Wood Coatings

This standard is issued under the ﬁxed designation D6958; 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 describe an evaluation procedure for

the determination of undesirable side-bonding of coatings for

wood ﬂooring. They provide two mechanical properties tests

for the quantitative determination of the cohesive strength of

wood coatings (tensile and lap shear).

1.2 The values stated in inch-pound units are to be regarded

as standard. The values given in parentheses are mathematical

conversions to SI units that are provided for information only

and are not considered standard.

1.3 This standard does not purport to address all of the

safety concerns, if any, associated with its use. It is the

responsibility of the user of this standard to establish appro-

priate safety, health, and environmental practices and deter-

mine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accor-

dance with internationally recognized principles on standard-

ization established in the Decision on Principles for the

Development of International Standards, Guides and Recom-

mendations issued by the World Trade Organization Technical

Barriers to Trade (TBT) Committee.

2. Referenced Documents

2.1 ASTM Standards:

D9 Terminology Relating to Wood and Wood-Based Prod-

ucts

D2370 Test Method for Tensile Properties of Organic Coat-

ings

D7438 Practice for Field Calibration and Application of

Hand-Held Moisture Meters

E4 Practices for Force Veriﬁcation of Testing Machines

2.2 Maple Flooring Manufacturers Association (MFMA):

Grading Rules for MFMA Hard Maple

2.3 National Wood Flooring Association (NWFA):

Technical Publication C200 Problems, Causes, and Cures

3. Terminology

3.1 Deﬁnitions—For general deﬁnitions of terms related to

wood, refer to Terminology D9.

3.2 Deﬁnitions of Terms Speciﬁc to This Standard:

3.2.1 panelization—condition caused by side-bonding, ex-

cessive installation adhesive, substrate movement, or other

factors where localized gaps develop between ﬂooring strips

while adjacent boards remain in tight contact acting as a

composite panel instead of individual strips.

3.2.2 panelization failure—condition where localized exces-

sive gaps beyond speciﬁed limits develop between some strip

ﬂooring boards due to panelization.

3.2.3 percent wood failure—rupturing of wood ﬁbers in

strength tests on bonded specimens usually expressed as the

percentage of total area involved which shows such failure and

is the inverse of adhesive failure.

3.2.4 side-bonding—bonding of adjacent strips of wood

ﬂooring caused by the ﬂoor coating resulting in panelization.

3.2.4.1 Discussion—Side-bonding is most commonly

caused when installed wood ﬂooring boards have become

adhered to each other. Finish materials, especially water-based

products, that have seeped between the boards, and the glue

used on the ﬂooring tongue-and-groove joint are two common

sources of side-bonding. Side-bonding wood failure can occur

as side-bonded ﬂooring boards shrink due to loss of moisture

after installation.

3.2.5 side-bonding wood failure—failure of the wood within

a strip, as in classic wood failure, when the movement of the

strip within the ﬂoor is restrained from moisture-related

movement by side-bonding and the resulting stress overcomes

the tensile strength perpendicular to the grain of the wood strip.

3.2.6 tensile stress (nominal)—as used in Test Method

D2370, the load per original unit area at which a specimen fails

or yields in a tension (pull) test.

These test methods are under the jurisdiction of ASTM Committee D07 on

Wood and are the direct responsibility of Subcommittee D07.01 on Fundamental

Test Methods and Properties.

Current edition approved Oct. 1, 2020. Published October 2020. Originally

approved in 2003. Last previous edition approved in 2014 as D6958 – 03 (2014).

DOI: 10.1520/D6958-20.

For referenced ASTM standards, visit the ASTM website, www.astm.org, or

contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM

Standards volume information, refer to the standard’s Document Summary page on

the ASTM website.

Available from the Maple Flooring Manufacturers Association, Inc. (MFMA),

1425 Tri State Parkway, Suite 110, Gurnee, IL 60031, http://www.mapleﬂoor.org.

Available from the National Wood Flooring Association (NWFA), 111 Ches-

terﬁeld Industrial Boulevard, Chesterﬁeld, MO 63005, http://www.nwfa.org

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.

TEST METHOD A—MAPLE BLOCK TENSILE

STRENGTH TEST

4. Signiﬁcance and Use

4.1 This test method was originally designed as a means of

quantitatively measuring the level of adhesion of the wood-

wood interface caused by a wood coatings system applied to

the substrate. The tensile test is useful in measuring bonding

strength of coatings, such as gymnasium coatings, in which the

wood strip ﬂooring primarily expands or contracts in response

to changes across the cross-sectional width of the strip ﬂoor.

4.2 This test method was further designed as a means of

measuring the side-bonding potential of wood coating systems.

5. Apparatus

5.1 Tensile Tester, of the constant rate of jaw separation

type, equipped with load cells having capacities of 100 to 1000

lb (445 to 4452 N), a data acquisition device capable of

capturing the peak load, and suitably sized grips to hold the test

specimens in place during testing. The machine must be

capable of maintaining a cross head velocity during testing of

0.1 in./min (2.54 mm/min). The load cells shall be calibrated to

an accuracy of at least 61 % in accordance with Practice E4.

5.2 Clamp Assembly, capable of holding assembled test

specimen and maintaining a clamp pressure of 100 psi (690

kPa) during curing.

5.3 Moisture Meter, meeting the requirements of Practice

D7438.

5.4 Foam Polybrushes, 1 in. (25.4 mm) wide.

6. Procedure

6.1 Material for testing shall be “Second and Better,”

“MFMA-PQ” grade certiﬁed hard maple (Acer saccharum)

parquet ﬂooring as speciﬁed in the Maple Flooring Manufac-

turers Association Parquet Flooring Grading Rules. These

rectangular, edge-grained strips shall have a planed ﬁnish and

⁄

60.03 in. (22.2 60.8 mm) in width by

⁄

60.01 in.

(11.1 60.3 mm) in thickness. The segments chosen for testing

shall be clear wood that is as straight-grained and free from

visual defects as possible. Unless required to satisfy the test

objectives and reported, adherence tests shall be conducted

using factory-planed surfaces that are representative of typical

ﬁeld conditions.

6.2 Blocks for testing shall be cut to a length of 1.25 60.01

in. (31.8 60.3 mm).

6.3 Test blocks shall be conditioned at 75 65 °F (24 6

3 °C) and 50 62 % relative humidity for a minimum of seven

days. These conditions are intended to produce at least a

surface equilibration moisture content of ~9 % (see X1.3).

After conditioning, use a moisture meter to determine the

moisture content of all test blocks in accordance with Practice

D7438, then calculate and report the average moisture content.

Alternative conditioning environments shall be permitted pro-

vided that they are reported.

6.4 A minimum of 20 test blocks shall be used to prepare a

minimum of ten assemblies for testing of each coating to be

evaluated (see Fig. 1).

6.5 Test assemblies consist of two test blocks “edge-glued”

using the ﬂoor coating as an adhesive (see Fig. 1). The coating

to be evaluated shall be applied using a polybrush to the

smooth edge of both test blocks at a rate of 500 65ft

/gal

(12.3 60.1 m

/L) or as speciﬁed by the coating manufacturer.

After a 5-min open time the test block pairs shall be assembled

by placing the coated surfaces together and clamping the joint

at 100 psi (690 kPa) pressure. Test assemblies shall remain

clamped for a minimum of 48 h.

6.6 Test assemblies shall be cured at 75 65 °F (24 63 °C)

and 50 62 % relative humidity for a minimum of seven days

including the clamp time. After curing, use a moisture meter to

determine the moisture content of all test assemblies in

accordance with Practice D7438, and calculate the average

moisture content. Alternative curing conditions shall be per-

mitted provided that they are reported.

6.7 Measure and record the length and width of the test

assembly to the nearest 0.01 in. (0.3 mm). Calculate the test

area of each test assembly.

6.8 Test assemblies shall be secured in a test machine using

grips that include either a universal joint on each end or a

means to adjust the grips to ensure that the direction of applied

force is perpendicular to the adhered surface (see Fig. 2). They

shall be pulled apart in tension at a rate of 0.1 in./min (2.54

mm/min).

6.9 Record the ultimate (peak) load, ultimate tensile stress,

location of failure (coating-coating interface, coating-wood

interface, within wood), an estimate of the percent wood

failure, and the average moisture content.

7. Report

7.1 Report the number of samples tested, any deviations

from the default conditioning or curing conditions, the location

FIG. 1 Test Method A, Maple Block Tensile Strength Test—Test

Block

D6958 − 20

of failure (coating-coating interface, coating-wood interface,

within wood), an estimate of the percent wood failure, the

average moisture content, and the average ultimate tensile

strength as load and stress.

8. Precision and Bias

8.1 Until sufficient data are available as a result of perform-

ing these tests, no speciﬁc precision and bias statement can be

expressed.

TEST METHOD B—MAPLE STRIP LAP SHEAR TEST

9. Signiﬁcance and Use

9.1 This test method was originally designed as a means of

quantitatively measuring the level of adhesion of the wood-

wood bond interface caused by a wood coatings system applied

to the substrate. The lap shear test is useful for measuring

bonding strength of coatings used on parquet or other similar

types of ﬂooring, where longitudinal movement of the ﬂooring

is a concern (for example, the shear force as the individual

wood pieces slide past each other).

9.2 This test method was further designed as a means of

measuring the side-bonding potential of wood coating systems.

10. Apparatus

10.1 Tensile Tester, of the constant rate of jaw separation

type, equipped with load cells having capacities of 100 to 1000

lb (445 to 4452 N), a data acquisition device capable of

capturing the peak load, and suitably sized grips to hold the test

specimens in place during testing. The machine must be

capable of maintaining a cross head velocity during testing of

0.1 in./min (2.54 mm/min). The load cells shall be calibrated to

an accuracy of at least 61 % in accordance with Practice E4.

10.2 Clamp Assembly, capable of holding assembled test

specimen and maintaining a clamp pressure of 100 psi (690

kPa) during curing.

10.3 Moisture Meter, meeting the requirements of Practice

D7438.

10.4 Foam Polybrushes, 1 in. (25.4 mm) wide.

11. Procedure

11.1 Source material for testing shall be “Second and

Better” grade, Maple Flooring Manufacturers Association cer-

tiﬁed hard maple (Acer saccharum) tongue-and-groove strip

ﬂooring, 2

⁄

60.03 in. (57.2 60.8 mm) in width by

⁄

0.01 in. (19.8 60.3 mm) in thickness. Alternatively, it shall be

permitted to use

⁄

in. (31.8 mm) quarter-sawn hard maple

lumber planed to an approximate thickness of 1 in. (25.4 mm)

for the source material. Regardless of source material type:

11.1.1 The growth rings shall be permitted to be at any

angle, from 0 to 90° inclusive, relative to the face.

11.1.2 The source material shall be chosen so that the

resulting strips shall be ﬂat and free from splits, knots, whorls,

and decay, that the angle of inclination of the grain across the

face of each test strip shall be not greater than 1 in 9, and that

the grain shall not be obviously inclined to the face (see

Appendix X2).

11.2 Test stock shall be prepared by cutting off the tongue

and planing the edge smooth. Strips for testing shall be planed

from this test stock to a width of 1.0 60.01 in. (25.4 60.3

mm), a length of 4.5 60.01 in. (114 60.3 mm), and a

thickness of 0.125 60.006 in. (3.18 60.15 mm). The face of

the strip to be adhered should be planed; the opposing face that

is not adhered shall be permitted to be planed or smoothly

sawn.

11.3 Test strips shall be conditioned at 75 65 °F (24 6

3 °C) and 50 62 % relative humidity for a minimum of seven

days. These conditions are intended to produce at least a

surface moisture content of ~9 %. Alternative conditioning

shall be permitted provided that it is reported. After

conditioning, use a moisture meter to determine the moisture

content of all test strips in accordance with Practice D7438,

and calculate the average moisture content.

11.4 A minimum of 20 test strips shall be used to prepare a

minimum of ten assemblies for testing of each coating to be

evaluated (see Fig. 3).

FIG. 2 Assembly Secured in Testing Machine

D6958 − 20

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摘要：

ASTM D6958-20 是一项由美国材料与试验协会（ASTM）发布的标准化测试方法，专门用于评估木基复合材料与金属紧固件之间的螺丝拔出阻力性能。该标准适用于定向刨花板（OSB）、胶合板、纤维板及其他木质复合板材，为工程设计与质量控制提供了关键力学指标。通过规定试件制备、加载速率、夹具要求及数据处理程序，ASTM D6958-20 帮助制造商、检测机构和建筑设计方统一测试条件，从而确保不同批次或来源的板材在承受螺丝连接时具备可靠的握钉力表现。该标准最新版本于2020年更新，纳入了更严格的公差控

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