GB/T 176-2025 Methods for chemical analysis of cement English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS 13.220.10
CCS H 57
National Standard of the People's Republic of China
GB/T 176-2025
Replaces GB/T 176-2017
Methods for chemical analysis of cement
水泥化学分析方法
Issue date: 2025-10-31 Implementation date: 2026-05-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
1 Scope
2 Normative References
3 Kinematics and Geometry
4 Basic requirements for testing
4.1 Number of tests and requirements
4.2 Mass, volume, titer, and representation of results
4.3 Permissible difference
4.4 Blank test
4.5 Ignition
4.6 Constant mass
4.7 Check for the presence of chloride ions (silver nitrate test)
4.8 Confirmation of test methods
4.9 Reagents
5 Preparation of test samples
6 Chemical analysis methods
6.1 Reagents and materials
6.2 Instruments and equipment
6.3 Determination of loss on ignition
7 X-ray fluorescence analysis method (alternative method)
7.1 Summary of method
7.2 Reagents
7.3 Instruments and equipment
7.4 Conversion of results and correction of total analysis results when sulfides and halides are present
7.5 Preparation of fusion beads and pressed pellets
8 Inductively coupled plasma optical emission spectrometry method (alternative method)
8.1 Summary of method
8.2 Reagents
8.3 Instruments and equipment
Appendix A (Informative) Calculation example of equivalence point in potentiometric titration of chloride ions
Appendix B (Informative) Reference chromatographic conditions and chromatogram for ion chromatography carbonate eluent
References
1 Scope
This document specifies the determination methods for L01, SO, IR, SiO₂, Fe₂O₃, Al₂O₃, CaO, MgO, TiO₂, Cl⁻, K₂O, Na₂O, S, MnO, P₂O₅, CO₂, ZnO, water-soluble R₂O, cement alkalinity (pH value), fCaO, and SrO in cement. The chemical analysis methods for cement are divided into reference methods and alternative methods. If multiple methods are provided for the same component, the reference method shall prevail in case of dispute.
This document applies to the determination of components in Portland cement, clinker, and raw materials.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute essential provisions of this document. For dated references, only the editions cited apply. For undated references, the latest edition (including all amendments) applies.
GB/T 2007.1 General rules for sampling and sample preparation of bulk mineral products—Manual sampling method
GB/T 5762 Chemical analysis methods for limestone, quicklime, and hydrated lime used in building materials
GB/T 6682 Specification and test methods for water for laboratory use
GB/T 8170 Rules for rounding off numerical values and representation of limiting values
GB/T 12573 Sampling method for cement
GB/T 15000 (all parts) Guide for reference materials
JG 196 Verification regulation for common glass volumetric apparatus
3 Terms and definitions
The terms and definitions defined in GB/T 15000 (all parts) and the following apply to this document.
3.1
Bead
A glass disc prepared by fusion for X-ray fluorescence spectrometry analysis.
3.2
Pellet
A compressed disc prepared by grinding for X-ray fluorescence spectrometry analysis.
3.3
Certified reference material (CRM)
A reference material accompanied by a certificate issued by authoritative procedures, providing one or more specified property values with their uncertainties and metrological traceability statements.
Source: GB/T 15000.3-2023, 3.2
3.4
Calibration sample
A reference material used for calibrating equipment or measurement procedures.
Source: GB/T 15000.3-2023, 3.7
4 General requirements for testing
4.1 Number of tests and requirements
The number of tests for each component determination shall be two. If the absolute difference between the two results falls within the allowable difference for the same laboratory (see Tables 4, 5, and 6), the average of the two results shall be reported as the determination result. For routine production control analysis, the number of tests for each component determination may be one.
It is recommended to determine the loss on ignition simultaneously during chemical analysis.
Except for loss on ignition, blank tests shall be conducted simultaneously for other determinations, and the results shall be corrected accordingly.
Photometric titration methods may be used to determine the endpoint.
4.2 Mass, volume, titer, and result representation
Mass shall be expressed in "grams (g)" with an accuracy of 0.0001 g. The volume of burettes shall be expressed in "milliliters (mL)" with a scale division not exceeding 0.10 mL, and readings shall be recorded to 0.01 mL. Titer shall be expressed in "milligrams per milliliter (mg/mL)."
The titer of benzoic acid-anhydrous ethanol standard titrant solution for calcium oxide determination shall be retained with three significant figures. The concentration of other standard titrant solutions, titer, and volume ratio shall be retained with four significant figures.
Unless otherwise specified, the analysis results for chloride ion and zinc oxide shall be expressed as mass fraction (%) to three decimal places, cement alkalinity as pH value to one decimal place, and other analysis results as mass fraction (%) to two decimal places.
Numerical rounding shall be performed in accordance with GB/T 8170.
4.3 Allowable difference
The allowable differences listed in this document are absolute differences, expressed as mass fraction (%). The allowable difference for the same laboratory refers to the allowable difference between two analysis results obtained by the same laboratory using the methods listed in this document for the same sample. If the allowable difference is exceeded, a third determination (or determination by a third party) shall be conducted within a short period. If the difference between the analysis result and the previous two or any one analysis result complies with the allowable difference, the average value shall be taken; otherwise, the cause shall be identified, and the analysis shall be repeated as per the above provisions.
The allowable difference for different laboratories refers to: when two laboratories analyze the same sample independently using the methods listed in this document, the difference between the average values of their analysis results shall comply with the allowable difference (see Tables 4, 5, and 6).
4.4 Blank test
Carry out the test without adding the sample, using the same amount of reagents and following the same steps, and correct the obtained results accordingly. For the alternative method (sodium hydroxide fusion-EDTA titration method) for calcium oxide determination, the blank test does not require adding potassium fluoride solution (6.1.56).
4.5 Ignition
Place the filter paper and precipitate or residue into a pre-ignited and constant-mass crucible, cover with the crucible lid (leaving a gap), and dry slowly to avoid flame ignition. After ashing and ashing until no black carbon particles remain, place in a high-temperature furnace (6.2.7) and ignite at the specified temperature.
4.6 Constant mass
After the first ignition, cooling, and weighing, check for constant mass by subjecting the vessel or sample to continuous ignition for 15 minutes, followed by cooling and weighing. When the difference between two consecutive weighings is less than 0.0005 g, constant mass is achieved.
