ASTM C1324-20a

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: C1324 − 20 C1324 − 20a
Standard Test Method for
Examination and Analysis of Hardened Masonry Mortar
This standard is issued under the fixed designation C1324; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers procedures for petrographic examination and chemical analysis of samples of masonry mortars. Based
upon such examination and analysis, proportions of components in masonry mortars can be determined.
NOTE 1—This method is also applicable to hydraulic cement-based stucco and plaster. Some historic mortars may contain non-resolvable constituents that
may interfere. However, significant information may be obtained by petrographic examinations.
1.2 Interpretations and calculations of chemical results are dependent upon results of the petrographic examination. The use of the
chemical results alone is contrary to the requirements of this test method.
1.3 Procedures for sampling, petrographic examination, chemical analysis, and calculations of component proportions are given
in the following sections:
Section
Sampling 7
Petrographic examination 8
Chemical analysis 9
Mortar proportion calculations 10
Report 11
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of the standard.
1.6 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.
1.7 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.
This test method is under the jurisdiction of ASTM Committee C12 on Mortars and Grouts for Unit Masonry and is the direct responsibility of Subcommittee C12.02
on Research and Methods of Test.
Current edition approved June 1, 2020Dec. 1, 2020. Published June 2020December 2020. Originally approved in 2002. Last previous edition approved in 20152020 as
C1324 – 15.C1324 – 20. DOI: 10.1520/C1324-20.10.1520/C1324-20A.
*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
C1324 − 20a
2. Referenced Documents
2.1 ASTM Standards:
C114 Test Methods for Chemical Analysis of Hydraulic Cement
C125 Terminology Relating to Concrete and Concrete Aggregates
C144 Specification for Aggregate for Masonry Mortar
C270 Specification for Mortar for Unit Masonry
C295/C295M Guide for Petrographic Examination of Aggregates for Concrete
C457/C457M Test Method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete
C823/C823M Practice for Examination and Sampling of Hardened Concrete in Constructions
C856/C856M Practice for Petrographic Examination of Hardened Concrete
C926 Specification for Application of Portland Cement-Based Plaster
C1084 Test Method for Portland-Cement Content of Hardened Hydraulic-Cement Concrete
C1180 Terminology of Mortar and Grout for Unit Masonry
D1193 Specification for Reagent Water
3. Terminology
3.1 Terms used in this test method are defined in Terminology standards C125, C1180, or the other referenced ASTM standards.
4. Significance and Use
4.1 This test method provides procedures for petrographic examination and chemical analysis of mortar for components of
masonry mortar. These components may include portland cement, hydrated calcitic or dolomitic lime, masonry cement, aggregates,
and air.
4.2 The test method consists of procedures and sub-procedures, each requiring a substantial degree of petrographic and chemical
skills and relatively elaborate instrumentation.
4.3 The chemical data considered together with results of petrographic examination of a mortar provide for calculation of
component proportions and thus allow a determination of mortar composition as represented by Types M, N, S, and O in Table
1 (Proportion Specification Requirements) of Specification C270.
4.4 Failure of a mortar to have the composition of any type as defined in Table 1 of Specification C270 does not necessarily mean
that the mortar does not meet the requirements of Specification C270. The mortar may meet the alternative requirements of Table
2 (Property Specification Requirements) of Specification C270.
4.5 The maleic acid method of analysis is not applicable for the analysis of mortar because it is greatly influenced by carbonation
and does not provide for the determination of calcium.
5. Qualifications of Petrographer and Chemist
5.1 Petrographer:
5.1.1 The petrographic examination requires the skill of a petrographer well versed in the petrographic methods of Practice
C856/C856M, Test Method C457/C457M, and Guide C295/C295M, and in the evaluations of portland cement-containing
materials and of masonry mortars.
5.1.2 The interpretation and evaluation of the petrographic data requires detailed knowledge of the requirements of Specification
C270.
5.2 Chemist:
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.
Erlin, Bernard and Hime, William G., “Evaluating Mortar Deterioration,” Association for Preservation Technology, 1987.
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5.2.1 The chemical analysis requires the skills of a chemist well versed in methods of chemical analysis, such as of Test Methods
C114 and Test Method C1084, and in the analytical procedures of these standards.
5.2.2 The interpretation and evaluation of the results of the chemical analysis requires detailed knowledge of the requirements of
Specification C270.
6. Apparatus, Reagents, and Materials
6.1 Apparatus used for the petrographic examination and preparation of specimens are given in Guide C295/C295M, Test Method
C457/C457M, and Practice C856/C856M.
6.2 The following apparatus for the chemical analysis shall be chosen from applicable items given in Test Methods C114 and
C1084 and from the following:
6.2.1 Crushers and pulverizers,
NOTE 2—Crushers and pulverizers may be obtained from many laboratory supply houses, and include chipmunk type jaw crushers, disc pulverizers, and
rotating puck devices.
6.2.2 Disk pulverizer,
6.2.3 Rotary mill (rotating puck),
6.2.4 Sieve, 300 μm (No. 50),
6.2.5 Ice bath or electric cooling apparatus,
6.2.6 Hot plate,
6.2.7 Buchner porcelain funnel,
6.2.8 Filter paper,
6.2.9 Beakers, 250-mL and 400-mL,
6.2.10 Platinum crucibles, and
6.2.11 Porcelain crucibles.
6.3 Reagents and Materials:
6.3.1 Soluble silica sub-procedure:
6.3.1.1 Hydrochloric acid, reagent grade, density 1.19 mg/m (1 + 3),
6.3.1.2 Sodium hydroxide, (10 g/L).
6.3.2 Calcium Oxide Sub-procedure—Use reagents as required in Test Methods C114.
6.3.3 Insoluble Residue Procedure—Hydrochloric acid, reagent grade, density 1.19 mg/m (1 + 4).
6.3.4 Water—All references to water shall be understood to mean reagent water Type I through IV of Specification D1193.
Hime, William G., and Erlin, Bernard, “Methods for Analyzing Mortar,” Proceedings of the Third North American Masonry Conference, Masonry Society, 1985.
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7. Sampling
7.1 The mortar sample should include intact pieces for petrographic analysis. A 10-g sample is usually sufficient for each
composite petrographic examination and chemical analysis. The sampling should provide for differentiating between pointing and
other mortars from the original mortar. For certain purposes, sampling may be done using procedures in Practice C823/C823M.
8. Petrographic Examination
8.1 General:
8.1.1 Petrographic examination refers to methods in Practice C856/C856M and principally to light microscopy and to use of a
petrographic microscope and a stereoscopic low power microscope. Ancillary techniques include X-ray diffractometry and
scanning electron microscopy.
8.1.2 X-ray diffraction analysis can be used to identify phases present in mortar. This information, in conjunction with the
petrographic microscopy information, is a basis for determining, for the chemical analysis, which calcium oxide or magnesium
oxide sub-procedure is necessary.
8.1.3 The petrographic and X-ray diffraction information is necessary for interpretations in calculating mortar composition.
8.2 Mortar:
8.2.1 Observe the mortar as appropriate, focusing attention on overall mortar appearance, characteristics of tooled surfaces,
fracture surfaces and surfaces contacting masonry units, and secondary substances (efflorescence and internal secondary products).
Describe and report the observations.
8.2.2 If X-ray diffraction methods are used, analyze for crystalline components in accordance with individual XRD equipment
techniques.
8.3 Aggregate:
8.3.1 Examine the aggregate component of the mortar for rock and mineral composition using methods of Guide C295/C295M
and Practice C856/C856M.
8.3.2 If components of the aggregate are acid-insoluble, gently break the mortar, and dissolve the paste matrix using dilute
hydrochloric acid, and thoroughly wash and filter the residue. Dry the aggregate residue, and examine it microscopically. The
residue may also be sorted into particle sizes using the sieving method of Specification C144. Aggregate particles broken during
the mortar breakdown will skew the gradation analysis results.
8.4 Paste—Examine the paste fraction of the mortar using methods of Practice C856/C856M. Components of the paste can include
residual (partially hydrated portland cement particles), hydration products of the portland cement and their carbonated equivalents,
hydrated lime (both calcitic and dolomitic) and carbonated hydrated lime, and finely ground mineral components such as
limestone, dolomite, slag, fly ash, clay, and pigments.
8.5 Air:
8.5.1 Examine the mortar for air voids and their configurations and distribution. Characterize the air voids as entrained or
entrapped as defined in Terminology C125 and Test Method C457/C457M, or both. Characterize air voids by locations, disposition,
and relative size.
8.5.2 Estimate the volume of air relative to the volume of the mortar, and report the estimate as percent air.
8.5.3 Measurements of characteristics of the air-void system can be made using Test Method C457/C457M. Usually, special
impregnation techniques will be necessary to provide a specimen suitable for the processing needed for this examination. An
impregnation technique is given in Test Method C457/C457M.
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8.6 Secondary Products—Examine the mortar, using methods of Practice C856/C856M, for secondary products in voids and on
tooled, fractured, and other surfaces. Describe, identify, and characterize products present.
8.7 Evaluation of Petrographic Data:
8.7.1 Mineralogical characteristics of the aggregate should be evaluated relative to components that could interfere in any
subsequent chemical analyses, any chemical or physical instability relative to alkali-silica and alkali-carbonate reactions, any
degradation due to freezing and thawing, and stability when exposed to moisture.
8.7.2 The paste should be evaluated so the original cementitious components used for preparing the mortar can be identified.
8.7.3 The air-void data should be evaluated so that the mortar can be classed as non-air-entrained or air-entrained.
8.7.4 The individual observations of aggregate, paste, air, secondary products, and tooled and other surfaces should be integrated
to establish overall compositional and textural characteristics of the mortar.
8.8 Miscellaneous—A report of the results of the petrographic examination should be prepared as a section of the overall report,
or as a separate report, depending upon the purpose of the study. The report should include details about each item in 8.2 through
8.7.
9. Chemical Analysis
9.1 Sample Preparation—Crush or grind a representative portion of the sample so that all the material passes a 300 μm (No. 50)
sieve. To minimize the production of very fine material, use several passes of the sample through the grinding equipment. Remove
the portion passing the sieve before regrinding the remainder of the sample. Thoroughly mix by coning from one paper to another
ten times.
9.2 Soluble Silica Sub-procedure (variation of method used in Test Method C1084):
9.2.1 Into two 250-mL beakers introduce 100 mL 1 + 4 HCl. Cool within the range of 3 to 5°C (38 to 41°F) using an ice bath or
electric cooling apparatus.
9.2.2 Slowly, over a 1-min period, introduce a 2.00-g sample of crushed mortar. Maintain the 3 to 5°C temperature for a 5-min
period, and stir the mixture either continuously or at least several times during this period.
NOTE 3—Observation of the solution during the introduction of the sample may provide useful information. Rapid effervescence indicates a substantial
amount of calcite or carbonated paste. Slow effervescence suggests a dolomite aggregate.
9.2.3 Decant through a Buchner porcelain funnel fitted snugly with two disks of a quantitative filter paper for fine precipitates,
Type II, Class G filter paper. Once the filtration has begun, take care so the mat and accumulated residue do not dry completely
until the filtration process is complete. Regulate the suction to maintain a rapid rate of filtration during the greater part of the
filtration process. Retain as much of the residue in the beaker as possible. Wash twice by decantation with hot water. Save the
filtrate. Carefully transfer the filter paper from the funnel to the beaker containing the balance of the residue so that no residue is
lost. Add 75 mL of hot sodium hydroxide solution (10 g/L) to the residue while stirring, macerate the filter paper, and digest for
15 min. During the digestion, occasionally stir the mixture. Decant as before, and wash twice with hot water until the filtrate is
neutral to litmus. Combine the filtrates in a 400-mL beaker.
9.2.4 Proceed to analyze as provided in 9.2.5 and 9.2.6, or analyze the soluble silica by any instrumental method found acceptable
for cement analysis in accordance with the performance requirement for rapid methods of Test Methods C114, provided it can be
applied to the filtrate.
The sole source of supply of the Stir-Kool Model SK-12 known to the committee at this time is Thermoelectrics Unlimited, Wilmington, DE. If you are aware of
alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible
technical committee, which you may attend.
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NOTE 4—Suitable instrumental techniques may include atomic absorption or inductively coupled plasma spectroscopy.
9.2.5 Evaporate to dryness taking great care to minimize spattering, bake at not over 120°C (248°F) for 1 h, moisten with
hydrochloric acid (density 1.19 g/mL), evaporate and bake again. Take up filtration in 75 mL of hydrochloric acid (1 + 3). Heat
to boiling, filter through an ashless filter paper, and wash the residue with 50 mL of hot hydrochloric acid (1 + 9) and then with
hot water until the washings are free of chlorides. Transfer the filter paper and residue to a weighed platinum crucible, dry, an
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