ASTM C596-23

Standard Test Method for Drying Shrinkage of Mortar Containing Hydraulic Cement

SIGNIFICANCE AND USE
4.1 This test method establishes a selected set of conditions of temperature, relative humidity and rate of evaporation of the environment to which a mortar specimen of stated composition shall be subjected for a specified period of time during which its change in length is determined and designated “drying shrinkage.”  
4.2 The drying shrinkage of mortar as determined by this test method has a linear relation to the drying shrinkage of concrete made with the same cement and exposed to the same drying conditions.4 Hence this test method may be used when it is desired to develop data on the effect of a hydraulic cement on the drying shrinkage of concrete made with that cement.
SCOPE
1.1 This test method determines the change in length on drying of mortar bars containing hydraulic cement and graded standard sand.  
1.2 The values stated in SI units are to be regarded as standard. When combined standards are referenced, the selection of measurement system is at the user’s discretion subject to the requirements of the referenced 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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure).2  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Nov-2023
• ICS: 91.100.10 - Cement. Gypsum. Lime. Mortar
• Technical Committee: C01 - Cement
• Drafting Committee: C01.31 - Volume Change

Relations

• Replaces: ASTM C596-18 - Standard Test Method for Drying Shrinkage of Mortar Containing Hydraulic Cement
• Effective Date: 01-Dec-2023
• Refers: ASTM C219-24 - Standard Terminology Relating to Hydraulic and Other Inorganic Cements
• Effective Date: 01-Apr-2024
• Refers: ASTM C670-24a - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Feb-2024
• Refers: ASTM C670-24 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM C219-20a - Standard Terminology Relating to Hydraulic and Other Inorganic Cements
• Effective Date: 01-Aug-2020
• Refers: ASTM C670-15 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 15-Jun-2015
• Referred By: ASTM C563-20 - Standard Guide for Approximation of Optimum SO<inf>3</inf> in Hydraulic Cement
• Effective Date: 01-Dec-2023
• Referred By: ASTM C226-22 - Standard Specification for Air-Entraining Additions for Use in the Manufacture of Air-Entraining Hydraulic Cement
• Effective Date: 01-Dec-2023
• Referred By: ASTM C157/C157M-17 - Standard Test Method for Length Change of Hardened Hydraulic-Cement Mortar and Concrete
• Effective Date: 01-Dec-2023
• Referred By: ASTM C688-22 - Standard Specification for Functional Additions for Use in Hydraulic Cements
• Effective Date: 01-Dec-2023
• Referred By: ASTM C465-23 - Standard Specification for Processing Additions for Use in the Manufacture<brk/> of Hydraulic Cements
• Effective Date: 01-Dec-2023
• Referred By: ASTM C1600/C1600M-23 - Standard Specification for Rapid Hardening Hydraulic Cement
• Effective Date: 01-Dec-2023

Overview

ASTM C596-23 is the Standard Test Method for Drying Shrinkage of Mortar Containing Hydraulic Cement, issued by ASTM International. This method outlines standardized procedures to determine the change in length, or drying shrinkage, of mortar bars made with hydraulic cement and graded standard sand. The standard provides essential guidelines on specimen preparation, environmental controls, and measurement techniques, ensuring that test results are consistent and repeatable across laboratories.

Understanding mortar drying shrinkage is vital in the design and evaluation of cement-based building materials. Excessive shrinkage can lead to cracking, structural issues, and compromised durability in mortar and the corresponding concrete.

Key Topics

• Test Conditions and Environmental Control
  The method specifies precise conditions for temperature, relative humidity, and evaporation rate during specimen curing and testing to ensure measurement consistency.

• Specimen Preparation
  Procedures include batching mortar, molding specimens, and curing methods, utilizing SI units as standard. The method requires the use of hydraulic cement and graded standard sand.

• Measurement and Calculation
  The standard prescribes length measurements at specified intervals using a length comparator, and outlines procedures for calculating drying shrinkage as a percentage of the effective gauge length.

• Reporting and Precision
  ASTM C596-23 details requirements for reporting average shrinkage values and managing faulty specimens. Guidance is provided on achieving consistent repeatability, both within and across laboratories.

• Safety Considerations
  The document stresses appropriate safety, health, and environmental practices when working with hydraulic cement mixtures, which are caustic.

Applications

• Cement Evaluation and Quality Control
  Manufacturers, quality control laboratories, and researchers use ASTM C596-23 to assess the drying shrinkage potential of hydraulic cements, predicting their behavior in concrete products.

• Specification and Product Development
  This test method supports the specification and development of mortars and concretes that are less prone to shrinkage-induced cracking, enhancing the durability and performance of building structures.

• Research and Comparative Testing
  The standardized procedure enables comparative studies of different cement types, admixtures, or sand gradations, providing useful data for optimizing mix designs for reduced shrinkage.

• Regulatory and Industry Compliance
  ASTM C596-23 is frequently referenced in construction codes and contract specifications where high performance or durability is required.

Related Standards

ASTM C596-23 is closely associated with several other ASTM standards that support various aspects of cement and mortar testing, including:

• ASTM C157/C157M - Test Method for Length Change of Hardened Hydraulic-Cement Mortar and Concrete
• ASTM C219 - Terminology Relating to Hydraulic and Other Inorganic Cements
• ASTM C305 - Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars
• ASTM C490/C490M - Practice for Use of Apparatus for Length Change Determination
• ASTM C511 - Specification for Mixing Rooms, Moist Cabinets, and Storage Tanks
• ASTM C778 - Specification for Standard Sand
• ASTM C1437 - Test Method for Flow of Hydraulic Cement Mortar

Following these standards together ensures that testing and quality control processes for hydraulic cement mortars are reliable and in compliance with industry best practices.

---

Keywords: ASTM C596-23, drying shrinkage, hydraulic cement, mortar testing, standard test method, length change, building materials, cement quality, concrete durability, construction standards.

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: C596 − 23
Standard Test Method for
Drying Shrinkage of Mortar Containing Hydraulic Cement
This standard is issued under the fixed designation C596; 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* Pastes and Mortars of Plastic Consistency
C490/C490M Practice for Use of Apparatus for the Deter-
1.1 This test method determines the change in length on
mination of Length Change of Hardened Cement Paste,
drying of mortar bars containing hydraulic cement and graded
Mortar, and Concrete
standard sand.
C511 Specification for Mixing Rooms, Moist Cabinets,
1.2 The values stated in SI units are to be regarded as
Moist Rooms, and Water Storage Tanks Used in the
standard. When combined standards are referenced, the selec-
Testing of Hydraulic Cements and Concretes
tion of measurement system is at the user’s discretion subject
C670 Practice for Preparing Precision and Bias Statements
to the requirements of the referenced standard.
for Test Methods for Construction Materials
1.3 This standard does not purport to address all of the C778 Specification for Standard Sand
safety concerns, if any, associated with its use. It is the
C1005 Specification for Reference Masses and Devices for
responsibility of the user of this standard to establish appro- Determining Mass and Volume for Use in Physical Testing
priate safety, health, and environmental practices and deter-
of Hydraulic Cements
mine the applicability of regulatory limitations prior to use. C1437 Test Method for Flow of Hydraulic Cement Mortar
Warning—Fresh hydraulic cementitious mixtures are caustic
E177 Practice for Use of the Terms Precision and Bias in
and may cause chemical burns to skin and tissue upon ASTM Test Methods
prolonged exposure).
3. Terminology
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.1 The term “drying shrinkage” is defined as the decrease
ization established in the Decision on Principles for the
in length of the test specimen, where the decrease is caused by
Development of International Standards, Guides and Recom-
any factor other than externally applied forces under stated
mendations issued by the World Trade Organization Technical
conditions of temperature, relative humidity and evaporation
Barriers to Trade (TBT) Committee.
rate in the environment; the term includes the net effect of a
variety of phenomena tending to bring about both increases and
2. Referenced Documents
decreases in length during the period in which the test
specimens under consideration are stored in the environment
2.1 ASTM Standards:
and in which a number of processes, including hydration of the
C157/C157M Test Method for Length Change of Hardened
cement, are taking place at a variety of rates.
Hydraulic-Cement Mortar and Concrete
C219 Terminology Relating to Hydraulic and Other Inor-
3.2 Other terms used in this test method are defined in
ganic Cements
Terminology C219.
C305 Practice for Mechanical Mixing of Hydraulic Cement
4. Significance and Use
4.1 This test method establishes a selected set of conditions
This test method is under the jurisdiction of ASTM Committee C01 on Cement
of temperature, relative humidity and rate of evaporation of the
and is the direct responsibility of Subcommittee C01.31 on Volume Change.
environment to which a mortar specimen of stated composition
Current edition approved Dec. 1, 2023. Published December 2023. Originally
approved in 1967. Last previous edition approved in 2018 as C596 – 18. DOI:
shall be subjected for a specified period of time during which
10.1520/C0596-23.
its change in length is determined and designated “drying
Section on Safety, Manual of Cement Testing, Annual Book of Standards,Vol
shrinkage.”
04.01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.2 The drying shrinkage of mortar as determined by this
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
test method has a linear relation to the drying shrinkage of
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. concrete made with the same cement and exposed to the same
*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
C596 − 23
drying conditions. Hence this test method may be used when 8.1.3 Water Storage Tank—The water temperature and lime-
it is desired to develop data on the effect of a hydraulic cement saturation state of the water storage tank shall conform to the
on the drying shrinkage of concrete made with that cement. requirements of Specification C511.
8.1.4 Drying Room and Controls—The drying room and
5. Apparatus
controls shall conform to the requirements of Test Method
C157/C157M.
5.1 Weighing Devices and Weights—Weighing devices and
weights used in determining the mass of materials for mortar
8.2 Curing and Storage—Cure, store, and take comparator
mixtures shall conform to the requirements of Specification
readings of the test specimens as required by Test Method
C1005.
C157/C157M, except as indicated in 9.3 of the Procedure.
5.2 Glass Graduates—Glass graduates of suitable capacities
9. Procedure
shall conform to the requirements of Specification C1005.
9.1 Prepare the specimen molds as required by Practice
5.3 Molds—Molds shall conform to the requirements of
C490/C490M.
Practice C490/C490M for mortars.
9.2 Prepare the test specimens.
5.4 Trowel—The trowel shall have a straight-edged steel
9.2.1 Mortar Proportions—A batch of mortar shall consist
blade 100 mm to 150 mm in length.
of 750 g of cement, 1500 g of graded standard sand, and an
5.5 Tamper—The tamper shall conform to the requirements
amount of mixing water sufficient to produce a flow of 105 %
of Test Method C157/C157M.
to 115 %. The flow shall be determined in conformance with
the procedure as described in Test Method C1437.
5.6 Demolding Apparatus—The demolding apparatus shall
9.2.2 Mixing Mortar—Mix the mortar in a mechanical
conform to the requirements of Test Method C157/C157M.
mixer as required by Practice C305.
5.7 Length Comparator—The length comparator shall con-
9.2.3 Molding of Specimens—Mold the specimens as re-
form to the requirements of Practice C490/C490M.
quired by Test Method C157/C157M.
9.3 Cure, store and take comparator reading of the test
6. Materials
specimens.
6.1 Graded standard sand shall conform to Specification
9.3.1 Moist cure the specimens in the molds for 24 h 6
C778.
30 min. If the strength of the specimens is insufficient to allow
proper removal from the mold at 24 h, moist cure in the mold
7. Sampling and Test Specimens
for 48 h 6 30 min.
7.1 A sample consists of four test specimens from a single
9.3.2 Remove the specimens from the molds and cure in
batch of mortar.
lime-saturated water for 48 h. If the specimens have been moist
7.2 Prepare at least one sample batch consisting of four test cured in the mold for 48 h, cure in lime-saturated water for
specimens according to Section 9. (Note 1). 24 h.
9.3.3 At the age of 72 h 6 30 min, remove the specimens
NOTE 1—It is preferable that three sample batches be prepared, for
from water, wipe with a damp cloth, and immediately obtain a
twelve specimens total, with each of the three batches being made on a
length comparator reading for each specimen.
different day.
9.3.4 Place the specimens in air storage for 25 days.
8. Conditioning
9.3.5 Obtain a length comparator reading for each specimen
after 4, 11, 18, and 25 days of air storage, which is equal to 1,
8.1 Temperature, Humidity, and Water Conditioning:
2, 3, and 4 weeks of tota
...

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: C596 − 18 C596 − 23
Standard Test Method for
Drying Shrinkage of Mortar Containing Hydraulic Cement
This standard is issued under the fixed designation C596; 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 determines the change in length on drying of mortar bars containing hydraulic cement and graded standard
sand.
1.2 The values stated in SI units are to be regarded as standard. When combined standards are referenced, the selection of
measurement system is at the user’s discretion subject to the requirements of the referenced 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 appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns
to skin and tissue upon prolonged exposure).
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C157/C157M Test Method for Length Change of Hardened Hydraulic-Cement Mortar and Concrete
C219 Terminology Relating to Hydraulic and Other Inorganic Cements
C305 Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic Consistency
C490/C490M Practice for Use of Apparatus for the Determination of Length Change of Hardened Cement Paste, Mortar, and
Concrete
C511 Specification for Mixing Rooms, Moist Cabinets, Moist Rooms, and Water Storage Tanks Used in the Testing of Hydraulic
Cements and Concretes
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
C778 Specification for Standard Sand
C1005 Specification for Reference Masses and Devices for Determining Mass and Volume for Use in Physical Testing of
Hydraulic Cements
C1437 Test Method for Flow of Hydraulic Cement Mortar
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
This test method is under the jurisdiction of ASTM Committee C01 on Cement and is the direct responsibility of Subcommittee C01.31 on Volume Change.
Current edition approved Dec. 1, 2018Dec. 1, 2023. Published December 2018December 2023. Originally approved in 1967. Last previous edition approved in 20172018
as C596 – 09 (2017).C596 – 18. DOI: 10.1520/C0596-18.10.1520/C0596-23.
Section on Safety, Manual of Cement Testing, Annual Book of Standards,Vol 04.01.
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.
*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
C596 − 23
3. Terminology
3.1 The term “drying shrinkage” is defined as the decrease in length of the test specimen, where the decrease is caused by any
factor other than externally applied forces under stated conditions of temperature, relative humidity and evaporation rate in the
environment; the term includes the net effect of a variety of phenomena tending to bring about both increases and decreases in
length during the period in which the test specimens under consideration are stored in the environment and in which a number of
processes, including hydration of the cement, are taking place at a variety of rates.
3.2 Other terms used in this test method are defined in Terminology C219.
4. Significance and Use
4.1 This test method establishes a selected set of conditions of temperature, relative humidity and rate of evaporation of the
environment to which a mortar specimen of stated composition shall be subjected for a specified period of time during which its
change in length is determined and designated “drying shrinkage”.shrinkage.”
4.2 The drying shrinkage of mortar as determined by this test method has a linear relation to the drying shrinkage of concrete made
with the same cement and exposed to the same drying conditions. Hence this test method may be used when it is desired to
develop data on the effect of a hydraulic cement on the drying shrinkage of concrete made with that cement.
5. Apparatus
5.1 Weighing Devices and Weights—Weighing devices and weights used in determining the mass of materials for mortar mixtures
shall conform to the requirements of Specification C1005.
5.2 Glass Graduates—Glass graduates of suitable capacities shall conform to the requirements of Specification C1005.
5.3 Molds—Molds shall conform to the requirements of Practice C490/C490M for mortars.
5.4 Trowel—The trowel shall have a straight-edged steel blade 100100 mm to 150 mm in length.
5.5 Tamper—The tamper shall conform to the requirements of Test Method C157/C157M.
5.6 Demolding Apparatus—The demolding apparatus shall conform to the requirements of Test Method C157/C157M.
5.7 Length Comparator—The length comparator shall conform to the requirements of Practice C490/C490M.
6. Temperature and Humidity
6.1 Laboratory—The temperature of the laboratory, dry materials, and mixing water, and the relative humidity of the air in the
laboratory shall conform to the requirements of Specification C511.
6.2 Moist Storage Facility—The temperature and humidity of the air in the moist storage facility shall conform to the requirements
of Specification C511.
6.3 Drying Room and Controls—The drying room and controls shall conform to the requirements of Test Method C157/C157M.
Data pertaining to the relation of the drying shrinkage of mortar test specimens and of the drying shrinkage of concrete test specimens as affected by the cement under
specified laboratory test conditions, may be found in RR:C01-0120, available from ASTM Headquarters; in a report of the California Division of Highways. “Significance
of the Test for Contraction of Mortar in Air with Respect to Performance of Cements in Concrete,” Oct. 18, 1961; and in the paper by Mardulier, F. J., Schneider, A. M.,
and Stockett, A. L., “An Analysis of Drying Shrinkage. Data for Portland Cement Mortar and Concrete,” Journal of Materials, JMLSA, Am. Soc. Testing Mats., Vol 2, No.
4, 1967, pp. 829–842. A relevant paper by H. T. Arni entitled “The Significance of the Correlation Coefficient for Analyzing Engineering Data” was published in Materials
Research and Standards, MTRSA, Am. Soc. Testing Mats., Vol. 11, No. 5, 1971, pp. 16–19.
C596 − 23
6. Graded Standard Sand Materials
6.1 The graded Graded standard sand shall conform to Specification C778.
7. Number ofSampling and Test Specimens
7.1 A sample consists of four test specimens from a single batch of mortar.
7.2 MakePrepare at least one sample batch consisting of four test specimens according to Section 9. (Note 1).
NOTE 1—Although the number of test specimens may consist of four specimens from a single batch of mortar, it It is preferable that twelve specimens
be made with four specimens being made from each of three batches, with each batch three sample batches be prepared, for twelve specimens total, with
each of the three batches being made on a different day.
8. Conditioning
8.1 Temperature, Humidity, and Water Conditioning:
8.1.1 Laboratory—The temperature of the laboratory, dry materials, and mixing water, and the relative humidity of the air in the
laboratory shall conform to the requirements of Specification C511.
8.1.2 Moist Cabinet and/or Moist Room—The temperature and humidity of the air in the moist cabinet or moist room shall
conform to the requirements of Specification C511.
8.1.3 Water Storage Tank—The water temperature and lime-saturation state of the water storage tank shall conform to the
requirements of Specification C511.
8.1.4 Drying Room and Controls—The drying room and controls shall conform to the requirements of Test Method C157/C157M.
8.2 Curing and Storage—Cure, store, and take comparator readings of the test specimens as required by Test Method
C157/C157M, except as indicated in 9.3 of the Procedure.
9. Preparation of Molds Procedure
9.1 Prepare the specimen molds as required by Practice C490/C490M.
9.2 Prepare the test specimens.
9.2.1 Mortar Proportions—A batch of mortar shall consist of 750 g of cement, 1500 g of graded standard sand, and an amount
of mixing water sufficient to produce a flow of 105 % to 115 %.
...