ASTM C1708/C1708M-23

Standard Test Methods for Self-leveling Mortars Containing Hydraulic Cements

SIGNIFICANCE AND USE
4.1 The test methods in this standard are used to evaluate freshly mixed properties such as the initial flow, flow retention, and healing time as well as hardened properties such as compressive strength, setting time, and flexural strength, of self-leveling mortars.  
4.2 Tests are conducted under standardized conditions for comparative purposes and results are not intended to be representative of performance under field conditions.
SCOPE
1.1 These test methods are appropriate to evaluate the performance of self-leveling mortars containing hydraulic cements that are used to improve the levelness, smoothness, and flatness of existing floors. These materials may be used as an underlayment to receive floor finishes, or as an overlayment to serve as the wear surface. The self-leveling mortars covered by these test methods consist of proprietary blends of hydraulic cements, along with fine aggregate, polymers, fillers, and other additives.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system 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.  
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: 14-Dec-2023
• ICS: 91.100.10 - Cement. Gypsum. Lime. Mortar
• Technical Committee: C09 - Concrete and Concrete Aggregates
• Drafting Committee: C09.43 - Packaged Dry Combined Materials

Relations

• Replaces: ASTM C1708/C1708M-19 - Standard Test Methods for Self-leveling Mortars Containing Hydraulic Cements
• Effective Date: 15-Dec-2023
• 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 C109/C109M-23 - Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 50 mm [2 in.] Cube Specimens)
• Effective Date: 15-Dec-2023
• Refers: ASTM C109/C109M-21 - Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or [50 mm] Cube Specimens)
• Effective Date: 15-Jul-2021
• Refers: ASTM C670-15 - Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
• Effective Date: 15-Jun-2015

Overview

ASTM C1708/C1708M-23 is the internationally recognized standard that defines methods for testing self-leveling mortars containing hydraulic cements. These mortars are specialized materials used to correct and improve the levelness, smoothness, and flatness of existing floors. ASTM C1708/C1708M-23 outlines laboratory procedures to assess both the freshly mixed and hardened properties of self-leveling mortars, including parameters such as initial flow, flow retention, healing time, compressive strength, setting time, flexural strength, dimensional stability, and abrasion resistance.

By following these standardized test methods, manufacturers, laboratories, and quality control experts can evaluate and compare the performance characteristics of different self-leveling mortars to ensure reliability and suitability for use as either underlayments or overlayments in construction and renovation projects.

Key Topics

• Freshly Mixed Properties

  • Initial flow: Assessment of the mortar’s ability to spread and self-level upon mixing.
  • Flow retention: Evaluation of how long the material maintains workable flow characteristics.
  • Healing time: Determination of the period during which the mortar can recover its levelness after disturbance.

• Hardened Properties

  • Compressive strength: Test to measure structural load-bearing capacity after curing.
  • Setting time: Determination of initial and final hardening using Vicat apparatus.
  • Flexural strength: Provides insight into performance under bending loads.
  • Length change: Monitors shrinkage and expansion for dimensional stability.
  • Abrasion resistance: Evaluates the material’s ability to withstand wear, crucial for overlayments and exposed surfaces.

• Material Composition

  • Self-leveling mortars as covered by ASTM C1708/C1708M-23 are proprietary blends of hydraulic cements, fine aggregates, polymers, fillers, and additives designed specifically for floor leveling applications.

• Testing Conditions

  • All laboratory tests must be conducted under tightly controlled temperature and humidity to enable reliable, comparative assessment.

Applications

ASTM C1708/C1708M-23 is widely used in various segments of the construction industry, providing significant value in:

• Floor Preparation:

  • Ensuring a flat, smooth, and level surface for the placement of floor finishes such as carpet, tile, wood, or resilient flooring.
  • As underlayments, these mortars offer a suitable substrate for receiving subsequent layers.

• Wear Surfaces:

  • When used as overlayments, self-leveling mortars can serve as a durable, abrasion-resistant final wear surface in both commercial and residential applications.

• Quality Control:

  • Manufacturers and independent test laboratories rely on these standardized test methods to validate product consistency, ensure compliance with specified requirements, and support product development and innovation.

• Comparative Product Evaluation:

  • Construction professionals and specifiers use the results from ASTM C1708/C1708M-23 testing to compare different products objectively and select the most appropriate material for their project needs.

Related Standards

The following ASTM standards are commonly referenced or used in conjunction with ASTM C1708/C1708M-23:

• ASTM C109/C109M: Test Method for Compressive Strength of Hydraulic Cement Mortars
• ASTM C191: Test Methods for Time of Setting of Hydraulic Cement by Vicat Needle
• ASTM C348: Test Method for Flexural Strength of Hydraulic-Cement Mortars
• ASTM C157/C157M: Test Method for Length Change of Hardened Hydraulic-Cement Mortar and Concrete
• ASTM C928/C928M: Specification for Packaged, Dry, Rapid-Hardening Cementitious Materials for Concrete Repairs
• ASTM F710: Practice for Preparing Concrete Floors to Receive Resilient Flooring

Adherence to ASTM C1708/C1708M-23 and its referenced standards supports improved quality, enhanced performance durability, and greater confidence in floor leveling and repair solutions across industries.

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: C1708/C1708M − 23
Standard Test Methods for
Self-leveling Mortars Containing Hydraulic Cements
This standard is issued under the fixed designation C1708/C1708M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 2. Referenced Documents
1.1 These test methods are appropriate to evaluate the 2.1 ASTM Standards:
performance of self-leveling mortars containing hydraulic C109/C109M Test Method for Compressive Strength of
cements that are used to improve the levelness, smoothness, Hydraulic Cement Mortars (Using 2-in. or [50 mm] Cube
and flatness of existing floors. These materials may be used as Specimens)
an underlayment to receive floor finishes, or as an overlayment C125 Terminology Relating to Concrete and Concrete Ag-
to serve as the wear surface. The self-leveling mortars covered gregates
by these test methods consist of proprietary blends of hydraulic C157/C157M Test Method for Length Change of Hardened
cements, along with fine aggregate, polymers, fillers, and other Hydraulic-Cement Mortar and Concrete
additives. C191 Test Methods for Time of Setting of Hydraulic Cement
by Vicat Needle
1.2 The values stated in either SI units or inch-pound units
C305 Practice for Mechanical Mixing of Hydraulic Cement
are to be regarded separately as standard. The values stated in
Pastes and Mortars of Plastic Consistency
each system are not necessarily exact equivalents; therefore, to
C348 Test Method for Flexural Strength of Hydraulic-
ensure conformance with the standard, each system shall be
Cement Mortars
used independently of the other, and values from the two
C490/C490M Practice for Use of Apparatus for the Deter-
systems shall not be combined.
mination of Length Change of Hardened Cement Paste,
1.3 This standard does not purport to address all of the
Mortar, and Concrete
safety concerns, if any, associated with its use. It is the
C511 Specification for Mixing Rooms, Moist Cabinets,
responsibility of the user of this standard to establish appro-
Moist Rooms, and Water Storage Tanks Used in the
priate safety, health, and environmental practices and deter-
Testing of Hydraulic Cements and Concretes
mine the applicability of regulatory limitations prior to use.
C670 Practice for Preparing Precision and Bias Statements
(Warning—Fresh hydraulic cementitious mixtures are caustic
for Test Methods for Construction Materials
and may cause chemical burns to skin and tissue upon
C778 Specification for Standard Sand
prolonged exposure.)
C928/C928M Specification for Packaged, Dry, Rapid-
1.4 This international standard was developed in accor-
Hardening Cementitious Materials for Concrete Repairs
dance with internationally recognized principles on standard-
C1005 Specification for Reference Masses and Devices for
ization established in the Decision on Principles for the
Determining Mass and Volume for Use in Physical Testing
Development of International Standards, Guides and Recom-
of Hydraulic Cements
mendations issued by the World Trade Organization Technical
C1107/C1107M Specification for Packaged Dry, Hydraulic-
Barriers to Trade (TBT) Committee.
Cement Grout (Nonshrink)
C1803 Guide for Abrasion Resistance of Mortar Surfaces
1 Using a Rotary Platform Abraser
These test methods are under the jurisdiction of ASTM Committee C09 on
Concrete and Concrete Aggregates and are the direct responsibility of Subcommittee D1200 Test Method for Viscosity by Ford Viscosity Cup
C09.43 on Packaged Dry Combined Materials.
Current edition approved Dec. 15, 2023. Published February 2024. Originally
approved in 2011. Last previous edition approved in 2019 as C1708/C1708M–19. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/C1708_C1708M-23. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Section on Safety Precautions, Manual of Aggregate and Concrete Testing, Standards volume information, refer to the standard’s Document Summary page on
Annual Book of ASTM Standards, Vol 04.02. 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
C1708/C1708M − 23
D5125 Test Method for Viscosity of Paints and Related the relative humidity of the laboratory shall be not less than
Materials by ISO Flow Cups 50 %. The self leveling mortar dry powder and mixing liquid
E691 Practice for Conducting an Interlaboratory Study to must be equilibrated to 23.0 °C 6 2.0 ºC [73.5 °F 6 3.5 ºF]
Determine the Precision of a Test Method prior to mixing. For optional tests at the manufacturer’s stated
F710 Practice for Preparing Concrete Floors to Receive temperature extremes, the curing and testing temperatures must
Resilient Flooring be within 62.0 °C [63.5 °F] of the stated extreme tempera-
tures.
3. Terminology
6. Sampling
3.1 Definitions—For definitions of terms used in these test
6.1 Sample according to the Sampling section of Specifica-
methods, refer to Terminology C125.
tion C1107/C1107M.
3.2 Definitions of Terms Specific to This Standard:
7. Mixing
3.2.1 flow, n—of self-leveling mortars, the ability of a
freshly-mixed, self-leveling mortar to spread under its own
7.1 Apparatus
weight or flow through an orifice.
7.1.1 Use the mixer and scraper as specified in Practice
C305. The standard batch size is 3000 g (See Note 1) of dry
3.2.2 healing, n—of self-leveling mortars, the ability of a
self-leveling mortar. Use a splash guard to prevent excessive
self-leveling mortar to return to its original state of levelness
splashing.
and smoothness after a specified cut is introduced into the
Warning—The clearances between the paddle and the bowl
surface.
specified in Practice C305 are suitable when using mortar made
3.2.2.1 Discussion—The specified cut is described in
with standard sand as described in Specification C778. To
8.4.4.3.
permit the mixer to operate freely and to avoid serious damage
3.2.3 mortar, self-leveling, n—mortar containing hydraulic
to the paddle and bowl when coarser aggregates are used, it
cement that, in the fresh state, exhibits flow sufficient to seek
may be necessary to set the clearance adjustment bracket to
gravitational leveling.
provide greater clearances than those specified in 4.1 of
3.2.4 overlayment, n—in flooring, a layer of material usu-
Practice C305.
ally placed upon the sub-floor that provides a smooth, even
7.1.2 Weighing devices used in determining the mass of
surface to be left exposed as the wear surface of the floor.
materials shall conform to Specification C1005.
3.2.5 time, healing, n—of self-leveling mortars, the period
7.1.3 A timer accurate to 1 s with a range of at least 60 min.
from the starting time until the moment when a specified cut
NOTE 1—This batch size is used for self-leveling mortars with a typical
leaves no observable indentation or ridge on the surface after 3 3
freshly mixed density of approximately 1920 kg/m [120 lb/ft ]. Adjust
setting.
the batch size as needed to accommodate densities significantly different
from the typical value.
3.2.5.1 Discussion—The specified cut is described in
8.4.4.3.
7.2 Procedure:
7.2.1 Mix the self-leveling mortar with liquid as prescribed
3.2.6 time, starting, n—of self-leveling mortars, the time
by the manufacturer. In the absence of manufacturer’s instruc-
when water is brought into contact with the dry ingredients of
tions the liquid content shall be adjusted to achieve an initial
a self-leveling mortar.
flow of 125 mm to 150 mm [5 in. to 6 in.] as per 8.4.
3.2.7 underlayment, n—in flooring, a layer of material
usually placed upon the sub-floor that provides a smooth, even NOTE 2—Water is the most common mixing liquid although latex
admixtures or other liquids may be recommended by some manufacturers.
base for flooring.
7.2.2 Add the entire quantity of mixing liquid to the bowl.
3.2.8 moisture resistance, n—of self-leveling mortars, the
Start the mixer on speed 1 and start the timer. Mix times are to
ability of a mortar to retain its properties after storage under tap
be observed within 65 s of the recommended times.
water.
7.2.3 Add the dry self-leveling mortar to the mixer while
4. Significance and Use mixing at speed 1 during the first 30 s. (0-30 s on timer.)
7.2.4 Mix for an additional 30 s period, at speed 1. (30 s-60
4.1 The test methods in this standard are used to evaluate
s on timer.)
freshly mixed properties such as the initial flow, flow retention,
7.2.5 Stop the mixer and quickly scrape down into the batch
and healing time as well as hardened properties such as
any mortar that may have collected on the side of the bowl or
compressive strength, setting time, and flexural strength, of
blade. This must be completed within 30 s (60-90 s on timer)
self-leveling mortars.
7.2.6 Mix at speed 2 for 240 s. (90-330 s on timer.)
4.2 Tests are conducted under standardized conditions for
7.2.7 In any case requiring a remixing interval, any mortar
comparative purposes and results are not intended to be
adhering to the side of the bowl shall be quickly scraped down
representative of performance under field conditions.
into the batch with the scraper prior to remixing.
5. Standard Laboratory Conditions
8. Initial Flow, Flow Retention, Viscosity by Flow Cup,
and Healing Time
5.1 Unless otherwise specified, curing and testing of speci-
mens shall be conducted at standard laboratory conditions 8.1 Scope—This test method measures the flow of freshly-
which are defined as 23.0 °C 6 2.0 ºC [73.5 °F 6 3.5 ºF] and mixed, self-leveling mortar by releasing it from a rigid tube
C1708/C1708M − 23
after a given time. The diameter of the spread mixture is plate in a vertical direction to a height of 50 mm to 100 mm
measured after a specified time. Flow retention is measured by [2 in. to 4 in.] within 2 s and allow the material to empty from
repeating the test on aged material. Viscosity by Flow Cup is the ring onto the glass plate.
measured using an ISO flow cup and a modified Test Method 8.4.1.3 Allow the mortar to spread for 240 s 6 10 s and
D5125 procedure on self leveling mortars that do not contain
measure the diameter of the spread in two directions at right
fibers greater than 1 mm in length. Healing time is determined angles using the length-measuring device. Record the average
by making specific cuts in the surface of the self-leveling
diameter as the initial flow of the self-leveling material.
mortar at regular time intervals and determining the latest time
8.4.1.4 Report the initial flow, mm [in.].
for which the mortar will still heal as evaluated after setting.
8.4.2 Flow Retention:
8.4.2.1 Repeat the flow test at 20 min and 30 min from the
8.2 Significance and Use—The flow of a self-leveling mor-
starting time and record the flow. Remix the material by using
tar is a measure of its placeability. Establishing an acceptable
the Practice C305 mixer, speed 1, for 5 to 10 s before filling the
flow range for the self-leveling mortar is critical to the proper
flow ring.
use of the self-leveling mortar. If the flow is too low, the
8.4.2.2 Report the flow retention as the flow, mm [in.] at
self-leveling mortar will not be self-leveling and if the flow is
20 min and 30 min.
too high, the designed properties of the self-leveling mortar
will be compromised. A proper flow range must be established
NOTE 5—Self-leveling mortars with flow retention times either shorter
in order to determine the proper water content to use when
or longer than 20 min-30 min reported in 8.4.2.2 may be measured at
appropriate 10 min intervals until material no longer flows out of the flow
evaluating the physical properties of the mortar. The flow
ring.
retention and healing time provide an indication of the useful
NOTE 6—An alternative procedure for flow retention is to fill three flow
working time of the mortar. The viscosity of the mortar gives
rings after the completion of mixing. The first ring is lifted immediately
additional information about the rheological characteristics,
and the second and third rings are lifted at 20 min and 30 min respectively
such as but not limited to, information about the ability to
from the starting time. This procedure is not recommended as the primary
convey the material in a mechanical pump. method of measuring flow retention but may be used to provide additional
information about the behavior of the material in a completely undisturbed
8.3 Apparatus
condition. The precision of this method is included in section 10.1.2.1 (2).
8.3.1 Flow Ring: A tube made of smooth, non-corrosive
8.4.3 Viscosity by Flow Cup Time:
1 1
material of 30.0 mm 6 0.1 mm [1 ⁄4 in. 6 ⁄16 in.] internal
8.4.3.1 Verify the cup is standardized using the procedure
diameter and 50.0 mm 6 0.1 mm [2 in. 6 ⁄16 in.] high.
outlined in Test Method D5125. Standardization shall be
8.3.2 A clean, dry 400 mm × 400 mm × 6 mm [16 in. ×
performed at least every 2 years and more frequently if wear of
16 in. × ⁄4 in.] square glass plate.
the cup is evident or if errant results are present.
8.3.3 A timer accurate to 1 s with a range of at least 60 min.
8.4.3.2 Position the flow cup in a stand and level the stand
8.3.4 A length-measuring device such as a ruler or tape
and cup. Position a receiving container under the cup.
measure divided into 1 mm [ ⁄16 in.] divisions at least 300 mm
8.4.3.3 Within 30 s from the completion of mixing, close the
[12 in.] long.
orifice with finger and slightly overfill the flow cup with
8.3.5 Rectangular pan with inside dimensions of at least
self-leveling mortar by pouring slowly over 10-15 seconds.
1 1
210 mm × 210 mm [8 ⁄2 in. × 8 ⁄2 in.] with a nominal depth of
8.4.3.4 Remove any meniscus formed by drawing straight
at least 9 mm [ ⁄8 in.] made of metal or glass not attacked by the
edge across the top of the cup.
self-leveling mortar.
8.4.3.5 Remove the finger to start the flow and simultane-
8.3.6 A metal bar 6 mm [ ⁄4 in.] thick, with square edges,
ously start a stopwatch.
and at least 150 mm [6 in.] long.
8.4.3.6 Watch for consistent flow. If sand or other contami-
NOTE 3—The side of a mold used to prepare specimens for Test Method
nant interrupts flow discard test and repeat with new material.
C157/C157M is acceptable for this purpose.
8.4.3.7 Looking into the top of the cup, stop the stopwatch
8.3.7 ISO Capillary Flow Cups as described in Test Method
when the orifice first becomes visible.
D5125.
NOTE 7— The cup need not be completely empty; some material may
remain on the sides. It is not necessary to see daylight through the orifice.
NOTE 4—ISO cups look like Ford cups, but instead of the non-capillary
hole in the bottom of the Ford cup, the ISO cup has a 20 mm long capillary
8.4.3.8 Report the cup used and the time that the hole
and is more like a true capillary viscometer. The typical orifice openings
became visible as the flow time.
used for self-leveling mortar are 6 mm and 8 mm. Ford cups are described
in Test Method D1200.
NOTE 8—This value can be used to determine the viscosity by looking
up the correct value on the chart provided with the flow cup.
8.4 Procedure:
NOTE 9—The test result can be influenced by the mixing energy
8.4.1 Initial Flow:
imparted to the mix. For laboratory testing purposes it is important to
8.4.1.1 Place the flow ring centrally on the glass plate and
follow Practice C305 and use the recommended mixing procedure. For
place this assembly on a firm horizontal surface not to depart
field testing the results may differ due to the different mixer used.
from horizontal by more than 0.5° (approximately equivalent NOTE 10—The flow test can be repeated at later times as needed. If
performed, remix the material by using the Practice C305 mixer at Speed
to 1 mm in 100 mm [0.12 in. in 12 in.]).
1 for 5 to 10 s before sampling.
8.4.1.2 Within 30 s from the completion of mixing, com-
8.4.4 Healing Time:
pletely fill the flow ring, immediately lift the flow ring and
simultaneously start the timer. Lift the flow ring from the glass 8.4.4.1 Place the pan on a level, vibration free surface.
C1708/C1708M − 23
8.4.4.2 Upon completion of mixing, pour self-leveling mor- 9.2 Setting Time
1 1
tar into the pan until a thickness of 6 mm 61 mm [ ⁄4 in. 6 ⁄16
9.2.1 Scope—This method covers the determination of the
in.] is obtained.
time of initial setting and time of final setting of self-leveling
8.4.4.3 Start making a full-depth cut in the test specimen at
mortars using the Vicat apparatus. Either procedure A or B as
10 min from the starting time using the 6 mm [ ⁄4 in.] thick
defined in Test Method C191 is acceptable.
metal bar (See Fig. 1). Hold the bar at approximately a 45°
9.2.2 Significance and Use—This test method determines
angle. Start at the far side of the pan about 25 mm [1 in.] from
the setting time of self-leveling mortars mixed to the normal
the left edge of the pan. Pull the bar smoothly through the mix
placement consistency as defined in 9.1. Special precautions
stopping at the near edge of the pan. Complete the cut in
are taken to ensure a proper seal around the Vicat ring.
approximately 5 s to 10 s. Record the time of the beginning of
9.2.3 Apparatus—Vicat Apparatus, in accordance with Test
each cut from the defined starting time.
Method C191.
8.4.4.4 Continue making cuts every 5 min until the material
9.2.4 Test Sample—The test sample shall consist of at least
no longer heals. Each cut shall be made about 25 mm [1 in.] to
300 mL of self-leveling mortar taken from a freshly-mixed
the right of the previous cut.
batch prepared in accordance with 7.2.
8.4.4.5 Allow the specimen to cure overnight before rating
9.2.5 Procedure:
healing time.
9.2.5.1 Seal the Vicat ring to the base plate in one of the
8.4.4.6 Healing time is determined by both touching and
following ways:
observing the cuts made the previous day. If there is an obvious
(1) Sealing wax method: Warm the Vicat conical ring and
ridge or indentation in the cut, the material is not healing (see
base plate to approximately 100 °C [212 °F]. Apply a thin film
definition). Make observations near the center of the cuts
of paraffin wax to the base of the conical ring and place the
avoiding areas near the edge of the pan.
waxed conical ring on the base plate. Place a weight on the
8.4.4.7 Report the healing time as the longest time for which
conical ring to ensure intimate contact with the base plate and
no obvious indentation or ridge is observed.
allow the conical ring and plate to cool to room temperature.
9. Physical Properties (2) High viscosity lubricant method: Apply a layer of
high-vacuum silicone grease or other suitable material to the
9.1 The following test methods are used to characterize the
base of the conical ring. Press the conical ring against the base
time of setting, strength, dimensional stability, and abrasion
plate so that the grease forms a seal between the ring and base
resistance of the self-leveling mortar and will require several
plate to prevent leakage.
batches to complete the testing. In order to ensure valid
9.2.5.2 Fill the conical ring apparatus with freshly mixed
comparisons, all tests shall be conducted at the same liquid
self-leveling mortar flush with its top within 2 min after
content using the amount and type of liquid prescribed by the
completion of mixing. Strike off flush with the top of the
manufacturer (See Note 2). In the absence of manufacturer’s
conical ring by a single oblique stroke of a margin trowel held
instructions the correct liquid content shall be established by
at a slight angle to the top of the ring.
using an initial trial batch for that purpose. Liquid content shall
9.2.5.3 Store the specimen on the bench top at laboratory
be adjusted to achieve a flow of 125 mm to 150 mm [5 in. to
conditions as described in 5.1.
6 in.]. The trial batch shall not be used for specimen prepara-
tion. It will then be necessary to mix additional batches of 9.2.5.4 Determine the time of initial setting and the time of
material using the same amount of liquid as was established by final setting using the procedure described in Test Method
the trial batch. Always use freshly mixed material for each test. C191 except that the first reading shall be taken approximately
FIG. 1 Full-Depth Cut in Test Specimen
C1708/C1708M − 23
30 min before the anticipated time of initial setting and the 9.4.2 Significance and Use—This test method affords a
needle wiped of adhering material between penetrations. means for determining the flexural strength of mortars that are
used as underlayments and overlayments in flooring applica-
NOTE 11—Fast setting self-leveling mortars will normally reach initial
tions. Prisms stored under water will provide information about
setting time in about 1 h to 3 h.
the moisture resistance of the mortar. Practice F710 requires
9.2.6 Report—The report shall include the following:
moisture resistant, resilient flooring underlayment.
9.2.6.1 The method that was used, Method A or B.
9.4.3 Apparatus—As described in Test Method C348.
9.2.6.2 Time of initial setting and final setting in h and min.
9.4.4 Procedure:
9.3 Compressive Strength:
9.4.4.1 Prepare six flexural strength specimens following
9.3.1 Scope—This test method covers determination of the
the consolidation procedure for fluid grouts of the compressive
compressive strength of self-leveling hydraulic cement
strength testing portion of Specification C1107/C1107M using
mortars, using 50-mm [2-in.] cube specimens, and it includes
watertight molds. If the optional water storage procedure is
an optional procedure in which specimens are stored under
required by the specifier of tests, prepare three additional
water before testing.
prisms for water storage.
9.3.2 Significance and Use—This test method affords a
9.4.4.2 The specified batch size will only allow for molding
means for determining the compressive strength of mortars that
six specimens. If additional test ages are desired, prepare
are used as underlayments and overlayments in flooring
additional batches using the same water content as the initial
applications. Cubes stored under water will provide informa-
batch.
tion about the moisture resistance of the mortar. Practice F710
requires moisture resistant, resilient flooring underlayment.
9.4.4.3 Cure the flexural strength specimens one day uncov-
9.3.3 Apparatus—As described in Test Method C109/
ered in the molds. At 23 h 6 ⁄2 h from the starting time,
C109M.
remove the prisms from the molds and determine the 1-day
9.3.4 Procedure:
flexural strength of three prisms in accordance with Test
Method C348.
9.3.4.1 Prepare nine compressive strength specimens fol-
lowing the consolidation procedure for fluid grouts of the
9.4.4.4 Cure the remaining specimens under standard labo-
compressive strength testing portion of Specification C1107/
ratory conditions as defined in 5.1 for 28 days and test the
C1107M using watertight molds. If the optional wet storage
second set of specimens in accordance with Test Method C348.
test is required by the specifier of tests, prepare three additional
9.4.4.5 If the optional water storage procedure is required,
specimens for water storage.
store three prisms in their molds for 24 h 6 ⁄2 h at the standard
9.3.4.2 Cure the compressive strength specimens one day
laboratory conditions defined in 5.1. Remove prisms from the
uncovered in the molds. At 23 h 6 ⁄2 h from the starting time,
molds and store at standard laboratory conditions for 6 d 6 3 h.
remove the cubes from the molds and determine the 1-day
Finally, submerge the prisms in tap water at standard tempera-
compressive strength of three cubes in accordance with Test
ture for 21 d 6 12 h. Test for flexural strength at 28 d 6 12 h
Method C109/C109M.
in accordance with Test Method C348.
9.3.4.3 Cure the remaining specimens under standard labo-
9.4.4.6 For the air cured specimens, determine the average
ratory conditions as defined in 5.1 and determine the compres-
flexural strength at 1 d and 28 d to the nearest 0.1 MPa [10 psi].
sive strength at 7 and 28 days from the starting time in
If the water storage procedure was used, report the average
accordance with Test Method C109/C109M. If the optional
flexural strength at 28 d to the nearest 0.1 MPa [10 psi] for
water storage procedure is required, store three specimens in
1 specimens stored in tap water
the mold for 24 h 6 ⁄2 h at the standard laboratory conditions
9.4.4.7 Report—The report shall include the following:
defined in 5.1. Remove specimens from the mold and store at
(1) Record the total maximum load indicated by the testing
standard laboratory conditions for 6 d 6 3 h. Finally, submerge
the specimens in tap water at standard temperature for 21 d 6 machine.
12 h. Test for compressive strength at 28 d 6 12 h in accor- (2) The calculated flexural strength for each specimen.
dance with Test Method C109/C109M.
(3) The average flexural strength of each age group of
9.3.4.4 For the air cured specimens, report the average specimens tested.
compressive strength at 1, 7 and 28 days to the nearest 0.1 MPa (4) If the optional wet storage procedure is performed,
[10 psi]. If the water storage procedure was used, report the report the average flexural strength in MPa [psi] at 28 days for
average compressive strength at 28 d to the nearest 0.1 MPa
specimens stored in water.
[10 psi] for specimens stored in tap water
9.5 Length Change:
NOTE 12—For rapid setting self-leveling mortars a 4-h test is optional.
9.5.1 Scope—This test method is carried out to assess the
shrinkage and expansion properties of self-leveling mortars by
9.4 Flexural Strength:
measuring the length change of specimens stored in air and
9.4.1 Scope—This test method covers determination of the
optionally in water for a specified period of time. The initial
flexural strength of self-leveling mortars using 40 mm ×
reading is made at 24 h after the starting time. Self-leveling
40 mm × 160 mm prism specimens as described in Test
Mortars exhibiting a fast setting time are known to have
Method C348 and it includes an optional procedure in which
specimens are stored under water before testing. significant length change before the initial reading of 24 h. As
C1708/C1708M − 23
specimens stored in water in accordance with Specification C928/C928M.
this length change may affect the performance of the product,
Report expansion as a positive number and shrinkage as a negative
other test methods may be needed to evaluate this early
number.
movement.
9.6 Abrasion Resistance:
9.5.2 Significance and Use—This test method determines
9.6.1 Scope—This method measures the abrasion mass loss
the length change of self-leveling mortars using
...

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: C1708/C1708M − 19 C1708/C1708M − 23
Standard Test Methods for
Self-leveling Mortars Containing Hydraulic Cements
This standard is issued under the fixed designation C1708/C1708M; 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 are appropriate to evaluate the performance of self-leveling mortars containing hydraulic cements that are
used to improve the levelness, smoothness, and flatness of existing floors. These materials may be used as an underlayment to
receive floor finishes, or as an overlayment to serve as the wear surface. The self-leveling mortars covered by these test methods
consist of proprietary blends of hydraulic cements, along with fine aggregate, polymers, fillers, and other additives.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system 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.
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 and healthsafety, 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:
C109/C109M Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or [50 mm] Cube Specimens)
C125 Terminology Relating to Concrete and Concrete Aggregates
C157/C157M Test Method for Length Change of Hardened Hydraulic-Cement Mortar and Concrete
C191 Test Methods for Time of Setting of Hydraulic Cement by Vicat Needle
C305 Practice for Mechanical Mixing of Hydraulic Cement Pastes and Mortars of Plastic Consistency
C348 Test Method for Flexural Strength of Hydraulic-Cement Mortars
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
These test methods are under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and are the direct responsibility of Subcommittee C09.43
on Packaged Dry Combined Materials.
Current edition approved Oct. 15, 2019Dec. 15, 2023. Published December 2019February 2024. Originally approved in 2011. Last previous edition approved in 20162019
as C1708/C1708M–16. DOI: 10.1520/C1708_C1708M-19.–19. DOI: 10.1520/C1708_C1708M-23.
Section on Safety Precautions, Manual of Aggregate and Concrete Testing, Annual Book of ASTM Standards, Vol 04.02.
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
C1708/C1708M − 23
C778 Specification for Standard Sand
C928/C928M Specification for Packaged, Dry, Rapid-Hardening Cementitious Materials for Concrete Repairs
C1005 Specification for Reference Masses and Devices for Determining Mass and Volume for Use in Physical Testing of
Hydraulic Cements
C1107/C1107M Specification for Packaged Dry, Hydraulic-Cement Grout (Nonshrink)
C1803 Guide for Abrasion Resistance of Mortar Surfaces Using a Rotary Platform Abraser
D1200 Test Method for Viscosity by Ford Viscosity Cup
D5125 Test Method for Viscosity of Paints and Related Materials by ISO Flow Cups
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
F710 Practice for Preparing Concrete Floors to Receive Resilient Flooring
3. Terminology
3.1 Definitions—For definitions of terms used in these test methods, refer to Terminology C125.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 flow, n—of self-leveling mortars, the ability of a freshly-mixed, self-leveling mortar to spread under its own weight or flow
through an orifice.
3.2.2 healing, n—of self-leveling mortars, the ability of a self-leveling mortar to return to its original state of levelness and
smoothness after a specified cut is introduced into the surface.
3.2.2.1 Discussion—
The specified cut is described in 8.4.4.3.
3.2.3 mortar, self-leveling, n—mortar containing hydraulic cement that, in the fresh state, exhibits flow sufficient to seek
gravitational leveling.
3.2.4 overlayment, n—in flooring, a layer of material usually placed upon the sub-floor that provides a smooth, even surface to
be left exposed as the wear surface of the floor.
3.2.5 time, healing, n—of self-leveling mortars, the period from the starting time until the moment when a specified cut leaves no
observable indentation or ridge on the surface after setting.
3.2.5.1 Discussion—
The specified cut is described in 8.4.4.3.
3.2.6 time, starting, n—of self-leveling mortars, the time when water is brought into contact with the dry ingredients of a
self-leveling mortar.
3.2.7 underlayment, n—in flooring, a layer of material usually placed upon the sub-floor that provides a smooth, even base for
flooring.
3.2.8 moisture resistance, n—of self-leveling mortars, the ability of a mortar to retain its properties after storage under tap water.
4. Significance and Use
4.1 The test methods in this standard are used to evaluate freshly mixed properties such as the initial flow, flow retention, and
healing time as well as hardened properties such as compressive strength, setting time, and flexural strength, of self-leveling
mortars.
4.2 Tests are conducted under standardized conditions for comparative purposes and results are not intended to be representative
of performance under field conditions.
5. Standard Laboratory Conditions
5.1 Unless otherwise specified, curing and testing of specimens shall be conducted at standard laboratory conditions which are
defined as 23.023.0 °C 6 2.0 ºC [73.5[73.5 °F 6 3.5 ºF] and the relative humidity of the laboratory shall be not less than 50 %.
C1708/C1708M − 23
The self leveling mortar dry powder and mixing liquid must be equilibrated to 23.023.0 °C 6 2.0 ºC [73.5[73.5 °F 6 3.5 ºF] prior
to mixing. For optional tests at the manufacturer’s stated temperature extremes, the curing and testing temperatures must be within
62.0 °C [63.5 °F] of the stated extreme temperatures.
6. Sampling
6.1 Sample according to the Sampling section of Specification C1107/C1107M.
7. Mixing
7.1 Apparatus
7.1.1 Use the mixer and scraper as specified in Practice C305. The standard batch size is 3000 g (See Note 1) of dry self-leveling
mortar. Use a splash guard to prevent excessive splashing.
Warning—The clearances between the paddle and the bowl specified in Practice C305 are suitable when using mortar made
with standard sand as described in Specification C778. To permit the mixer to operate freely and to avoid serious damage to the
paddle and bowl when coarser aggregates are used, it may be necessary to set the clearance adjustment bracket to provide greater
clearances than those specified in 4.1 of Practice C305.
7.1.2 Weighing devices used in determining the mass of materials shall conform to Specification C1005.
7.1.3 A timer accurate to 1 s with a range of at least 60 min.
3 3
NOTE 1—This batch size is used for self-leveling mortars with a typical freshly mixed density of approximately 1920 kg/m [120 lb/ft ]. Adjust the batch
size as needed to accommodate densities significantly different from the typical value.
7.2 ProcedureProcedure:
7.2.1 Mix the self-leveling mortar with liquid as prescribed by the manufacturer. In the absence of manufacturer’s instructions the
liquid content shall be adjusted to achieve an initial flow of 125125 mm to 150 mm [5[5 in. to 6 in.] as per 8.4.
NOTE 2—Water is the most common mixing liquid although latex admixtures or other liquids may be recommended by some manufacturers.
7.2.2 Add the entire quantity of mixing liquid to the bowl. Start the mixer on speed 1 and start the timer. Mix times are to be
observed within 65 s of the recommended times.
7.2.3 Add the dry self-leveling mortar to the mixer while mixing at speed 1 during the first 30 s. (0-30 s on timer)timer.)
7.2.4 Mix for an additional 30 s period, at speed 1. (30-60(30 s-60 s on timer)timer.)
7.2.5 Stop the mixer and quickly scrape down into the batch any mortar that may have collected on the side of the bowl or blade.
This must be completed within 30 s (60-90 s on timer)
7.2.6 Mix at speed 2 for 240 s. (90-330 s on timer)timer.)
7.2.7 In any case requiring a remixing interval, any mortar adhering to the side of the bowl shall be quickly scraped down into
the batch with the scraper prior to remixing.
8. Initial Flow, Flow Retention, Viscosity by Flow Cup, and Healing Time
8.1 Scope—This test method measures the flow of freshly-mixed, self-leveling mortar by releasing it from a rigid tube after a given
time. The diameter of the spread mixture is measured after a specified time. Flow retention is measured by repeating the test on
aged material. Viscosity by Flow Cup is measured using an ISO flow cup and a modified Test Method D5125 procedure on self
leveling mortars that do not contain fibers greater than 1 mm in length. Healing time is determined by making specific cuts in the
surface of the self-leveling mortar at regular time intervals and determining the latest time for which the mortar will still heal as
evaluated after setting.
C1708/C1708M − 23
8.2 Significance and Use—The flow of a self-leveling mortar is a measure of its placeability. Establishing an acceptable flow range
for the self-leveling mortar is critical to the proper use of the self-leveling mortar. If the flow is too low, the self-leveling mortar
will not be self-leveling and if the flow is too high, the designed properties of the self-leveling mortar will be compromised. A
proper flow range must be established in order to determine the proper water content to use when evaluating the physical properties
of the mortar. The flow retention and healing time provide an indication of the useful working time of the mortar. The viscosity
of the mortar gives additional information about the rheological characteristics, such as but not limited to, information about the
ability to convey the material in a mechanical pump.
8.3 Apparatus
1 1
8.3.1 Flow Ring: A tube made of smooth, non-corrosive material of 30.030.0 mm 6 0.1 mm [1 ⁄4 in. 6 ⁄16 in.] internal diameter
and 50.050.0 mm 6 0.1 mm [2[2 in. 6 ⁄16 in.] high.
8.3.2 A clean, dry 400 mm × 400 mm × 6 mm [16 in. × 16 in. 16 in. × ⁄4 in.] square glass plate.
8.3.3 A timer accurate to 1 s with a range of at least 60 min.
8.3.4 A length-measuring device such as a ruler or tape measure divided into 1 mm [ ⁄16 in.] divisions at least 300 mm [12 in.]
long.
1 1
8.3.5 Rectangular pan with inside dimensions of at least 210 mm 210 mm × 210 mm [8 ⁄2 in. × 8 ⁄2 in.] with a nominal depth of
at least 9 mm [ ⁄8 in.] made of metal or glass not attacked by the self-leveling mortar.
8.3.6 A metal bar 6 mm [ ⁄4 in.] thick, with square edges, and at least 150 mm [6 in.] long.
NOTE 3—The side of a mold used to prepare specimens for Test Method C157/C157M is acceptable for this purpose.
8.3.7 ISO Capillary Flow Cups as described in Test Method D5125.
NOTE 4—ISO cups look like Ford cups, but instead of the non-capillary hole in the bottom of the Ford cup, the ISO cup has a 20 mm long capillary and
is more like a true capillary viscometer. The typical orifice openings used for self-leveling mortar are 6 mm and 8 mm. Ford cups are described in Test
Method D1200.
8.4 ProcedureProcedure:
8.4.1 Initial Flow:
8.4.1.1 Place the flow ring centrally on the glass plate and place this assembly on a firm horizontal surface not to depart from
horizontal by more than 0.5° (approximately equivalent to 1 mm in 100 mm [0.12 in. in 12 in.]).
8.4.1.2 Within 30 s from the completion of mixing, completely fill the flow ring, immediately lift the flow ring and simultaneously
start the timer. Lift the flow ring from the glass plate in a vertical direction to a height of 50 mm to 100 mm [2[2 in. to 4 in.] within
2 s and allow the material to empty from the ring onto the glass plate.
8.4.1.3 Allow the mortar to spread for 240 s 6 10 s and measure the diameter of the spread in two directions at right angles using
the length-measuring device. Record the average diameter as the initial flow of the self-leveling material.
8.4.1.4 Report the initial flow, mm [in.].
8.4.2 Flow Retention:
8.4.2.1 Repeat the flow test at 20 min and 30 min from the starting time and record the flow. Remix the material by using the
Practice C305 mixer, speed 1, for 5 to 10 s before filling the flow ring.
8.4.2.2 Report the flow retention as the flow, mm [in.] at 20 min and 30 min.20 min and 30 min.
C1708/C1708M − 23
NOTE 5—Self-leveling mortars with flow retention times either shorter or longer than 20-30 20 min-30 min reported in 8.4.2.2 may be measured at
appropriate 10 min intervals until material no longer flows out of the flow ring.
NOTE 6—An alternatealternative procedure for flow retention is to fill three flow rings after the completion of mixing. The first ring is lifted immediately
and the second and third rings are lifted at 20 min and 30 min respectively from the starting time. This procedure is not recommended as the primary
method of measuring flow retention but may be used to provide additional information about the behavior of the material in a completely undisturbed
condition. The precision of this method is included in section 10.1.2.1 (2).
8.4.3 Viscosity by Flow Cup Time:—Time:
8.4.3.1 Verify the cup is standardized using the procedure outlined in Test Method D5125. Standardization shall be performed at
least every 2 years and more frequently if wear of the cup is evident or if errant results are present.
8.4.3.2 Position the flow cup in a stand and level the stand and cup. Position a receiving container under the cup.
8.4.3.3 Within 30 s from the completion of mixing, close the orifice with finger and slightly overfill the flow cup with self-leveling
mortar by pouring slowly over 10-15 seconds.
8.4.3.4 Remove any meniscus formed by drawing straight edge across the top of the cup.
8.4.3.5 Remove the finger to start the flow and simultaneously start a stopwatch.
8.4.3.6 Watch for consistent flow. If sand or other contaminant interrupts flow discard test and repeat with new material.
8.4.3.7 Looking into the top of the cup, stop the stopwatch when the orifice first becomes visible.
NOTE 7— The cup need not be completely empty; some material may remain on the sides. It is not necessary to see daylight through the orifice.
8.4.3.8 Report the cup used and the time that the hole became visible as the flow time.
NOTE 8—This value can be used to determine the viscosity by looking up the correct value on the chart provided with the flow cup.
NOTE 9—The test result can be influenced by the mixing energy imparted to the mix. For laboratory testing purposes it is important to follow Practice
C305 and use the recommended mixing procedure. For field testing the results may differ due to the different mixer used.
NOTE 10—The flow test can be repeated at later times as needed. If performed, remix the material by using the Practice C305 mixer at Speed 1 for 5 to
10 s before sampling.
8.4.4 Healing Time:
8.4.4.1 Place the pan on a level, vibration free surface.
1 1
8.4.4.2 Upon completion of mixing, pour self-leveling mortar into the pan until a thickness of 6 mm 61 mm [ ⁄4 in. 6 ⁄16 in.]
is obtained.
8.4.4.3 Start making a full-depth cut in the test specimen at 10 min from the starting time using the 6 mm [ ⁄4 in.] thick metal bar
(See Fig. 1). Hold the bar at approximately a 45° angle. Start at the far side of the pan about 25 mm [1 in.] from the left edge of
the pan. Pull the bar smoothly through the mix stopping at the near edge of the pan. Complete the cut in approximately 5 s to 10
s. Record the time of the beginning of each cut from the defined starting time.
8.4.4.4 Continue making cuts every 5 min until the material no longer heals. Each cut shall be made about 25 mm [1 in.] to the
right of the previous cut.
8.4.4.5 Allow the specimen to cure overnight before rating healing time.
8.4.4.6 Healing time is determined by both touching and observing the cuts made the previous day. If there is an obvious ridge
or indentation in the cut, the material is not healing (see definition). Make observations near the center of the cuts avoiding areas
near the edge of the pan.
C1708/C1708M − 23
FIG. 1 Full-Depth Cut in Test Specimen
8.4.4.7 Report the healing time as the longest time for which no obvious indentation or ridge is observed.
9. Physical Properties
9.1 The following test methods are used to characterize the time of setting, strength, dimensional stability, and abrasion resistance
of the self-leveling mortar and will require several batches to complete the testing. In order to ensure valid comparisons, all tests
shall be conducted at the same liquid content using the amount and type of liquid prescribed by the manufacturer (See Note 2).
In the absence of manufacturer’s instructions the correct liquid content shall be established by using an initial trial batch for that
purpose. Liquid content shall be adjusted to achieve a flow of 125 mm to 150 mm [5 in. to 6 in.]. The trial batch shall not be used
for specimen preparation. It will then be necessary to mix additional batches of material using the same amount of liquid as was
established by the trial batch. Always use freshly mixed material for each test.
9.2 Setting Time
9.2.1 Scope—This method covers the determination of the time of initial setting and time of final setting of self-leveling mortars
using the Vicat apparatus. Either procedure A or B as defined in Test Method C191 is acceptable.
9.2.2 Significance and Use—This test method determines the setting time of self-leveling mortars mixed to the normal placement
consistency as defined in 9.1. Special precautions are taken to ensure a proper seal around the Vicat ring.
9.2.3 Apparatus—Vicat Apparatus, in accordance with Test Method C191.
9.2.4 Test Sample—The test sample shall consist of at least 300 mL of self-leveling mortar taken from a freshly-mixed batch
prepared in accordance with 7.2.
9.2.5 Procedure:
9.2.5.1 Seal the Vicat ring to the base plate in one of the following ways:
(1) Sealing wax method: Warm the Vicat conical ring and base plate to approximately 100 °C [212 °F]. Apply a thin film of
paraffin wax to the base of the conical ring and place the waxed conical ring on the base plate. Place a weight on the conical ring
to ensure intimate contact with the base plate and allow the conical ring and plate to cool to room temperature.
(2) High viscosity lubricant method: Apply a layer of high-vacuum silicone grease or other suitable material to the base of the
conical ring. Press the conical ring against the base plate so that the grease forms a seal between the ring and base plate to prevent
leakage.
9.2.5.2 Fill the conical ring apparatus with freshly mixed self-leveling mortar flush with its top within 2 min after completion of
mixing. Strike off flush with the top of the conical ring by a single oblique stroke of a margin trowel held at a slight angle to the
top of the ring.
C1708/C1708M − 23
9.2.5.3 Store the specimen on the bench top at laboratory conditions as described in 5.1.
9.2.5.4 Determine the time of initial setting and the time of final setting using the procedure described in Test Method C191 except
that the first reading shall be taken approximately 30 min before the anticipated time of initial setting and the needle wiped of
adhering material between penetrations.
NOTE 11—Fast setting self-leveling mortars will normally reach initial setting time in about 1 h to 3 h.
9.2.6 Report—The report shall include the following:
9.2.6.1 The method that was used, Method A or B.
9.2.6.2 Time of initial setting and final setting in h and min.
9.3 Compressive StrengthStrength:
9.3.1 Scope—This test method covers determination of the compressive strength of self-leveling hydraulic cement mortars, using
50-mm [2-in.] cube specimens.specimens, and it includes an optional procedure in which specimens are stored under water before
testing.
9.3.2 Significance and Use—This test method affords a means for determining the compressive strength of mortars that are used
as underlayments and overlayments in flooring applications. Cubes stored under water will provide information about the moisture
resistance of the mortar. Practice F710 requires moisture resistant, resilient flooring underlayment.
9.3.3 Apparatus—As described in Test Method C109/C109M.
9.3.4 Procedure:
9.3.4.1 Prepare nine compressive strength specimens following the consolidation procedure for fluid grouts of the compressive
strength testing portion of Specification C1107/C1107M using watertight molds. If the optional wet storage test is required by the
specifier of tests, prepare three additional specimens for water storage.
9.3.4.2 Cure the compressive strength specimens one day uncovered in the molds. At 2323 h 6 ⁄2 h from the starting time, remove
the cubes from the molds and determine the 1-day compressive strength of three cubes in accordance with Test Method
C109/C109M.
9.3.4.3 Cure the remaining specimens under standard laboratory conditions as defined in 5.1 and determine the compressive
strength at 7 and 28 days from the starting time in accordance with Test Method C109/C109M. If the optional water storage
procedure is required, store three specimens in the mold for 24 h 6 ⁄2 h at the standard laboratory conditions defined in 5.1.
Remove specimens from the mold and store at standard laboratory conditions for 6 d 6 3 h. Finally, submerge the specimens in
tap water at standard temperature for 21 d 6 12 h. Test for compressive strength at 28 d 6 12 h in accordance with Test Method
C109/C109M.
9.3.4.4 Report the For the air cured specimens, report the average compressive strength in MPa [psi] at 1, 7,7 and 28 days to the
nearest 0.1 MPa [10 psi].[10 psi]. If the water storage procedure was used, report the average compressive strength at 28 d to the
nearest 0.1 MPa [10 psi] for specimens stored in tap water
NOTE 12—For rapid setting self-leveling mortars a 4-h test is optional.
9.4 Flexural Strength:
9.4.1 Scope—This test method covers determination of the flexural strength of self-leveling mortars using 40 × 40 ×
160-mm40 mm × 40 mm × 160 mm prism specimens as described in Test Method C348. and it includes an optional procedure in
which specimens are stored under water before testing.
9.4.2 Significance and Use—This test method affords a means for determining the flexural strength of mortars that are used as
C1708/C1708M − 23
underlayments and overlayments in flooring applications. Prisms stored under water will provide information about the moisture
resistance of the mortar. Practice F710 requires moisture resistant, resilient flooring underlayment.
9.4.3 Apparatus—As described in Test Method C348.
9.4.4 Procedure:
9.4.4.1 Prepare six flexural strength specimens following the consolidation procedure for fluid grouts of the compressive strength
testing portion of Specification C1107/C1107M using watertight molds. If the optional water storage procedure is required by the
specifier of tests, prepare three additional prisms for water storage.
9.4.4.2 The specified batch size will only allow for molding six specimens. If additional test ages are desired, prepare additional
batches using the same water content as the initial batch.
9.4.4.3 Cure the flexural strength specimens one day uncovered in the molds. At 23 h 6 ⁄2 h from the starting time, remove the
prisms from the molds and determine the 1-day flexural strength of three prisms in accordance with Test Method C348.
9.4.4.4 Cure the remaining specimens under standard laboratory conditions as defined in 5.1 for 28 days and test the second set
of specimens in accordance with Test Method C348.
9.4.4.5 If the optional water storage procedure is required, store three prisms in their molds for 24 h 6 ⁄2 h at the standard
laboratory conditions defined in 5.1. Remove prisms from the molds and store at standard laboratory conditions for 6 d 6 3 h.
Finally, submerge the prisms in tap water at standard temperature for 21 d 6 12 h. Test for flexural strength at 28 d 6 12 h in
accordance with Test Method C348.
9.4.4.6 Report the For the air cured specimens, determine the average flexural strength in MPa [psi] at 1 and 28 days at 1 d and
28 d to the nearest 0.1 MPa [10 psi]. If the water storage procedure was used, report the average flexural strength at 28 d to the
nearest 0.1 MPa [10 psi].psi] for specimens stored in tap water
9.4.4.7 Report—The report shall include the following:
(1) Record the total maximum load indicated by the testing machine.
(2) The calculated flexural strength for each specimen.
(3) The average flexural strength of each age group of specimens tested.
(4) If the optional wet storage procedure is performed, report the average flexural strength in MPa [psi] at 28 days for
specimens stored in water.
9.5 Length Change:
9.5.1 Scope—This test method is carried out to assess the shrinkage and expansion properties of self-leveling mortars by
measuring the length change of specimens stored in air and optionally in water for a specified period of time. The initial reading
is made at 24 h after the starting time. Self-leveling Mortars exhibiting a fast setting time are known to have significant length
change before the initial reading of 24 h. As this length change may affect the performance of the product, other test methods may
be needed to evaluate this early movement.
9.5.2 Significance and Use—This test method determines the length change of self-leveling mortars using an unrestrained method
as described in Test Method C157/C157M. Prisms stored under water will provide information about the moisture resistance of
the mortar. Practice F710 requires moisture resista
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