GB/T 748-2023 English PDF (GBT748-2023)

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GB/T 748-2023: Sulfate resistance portland cement
GB/T 748-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 91.100.10
CCS Q 11
Replacing GB/T 748-2005
Sulfate resistance portland cement
抗硫酸盐硅酸盐水泥
ISSUED ON: MAY 23, 2023
IMPLEMENTED ON: DECEMBER 1, 2023
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 6
2 Normative references ... 6
3 Terms and definitions ... 7
4 Materials ... 7
5 Strength grade ... 8
6 Technical requirements ... 8
7 Test method ... 10
8 Inspection rules ... 11
9 Delivery and acceptance ... 13
10 Packaging, marking, transportation, and storage ... 13
Appendix A (Normative) Calculation of mineral composition in cement ... 15
Sulfate resistance portland cement
1 Scope
This document specifies the materials, strength grades, technical requirements, test
methods, inspection rules, packaging, marking, transportation, and storage of sulfate-
resistant portland cement.
This document applies to the production and application of sulfate-resistant portland
cement.
2 Normative references
The following documents contain the provisions which, through normative reference in
this document, constitute the essential provisions of this document. For the dated
referenced documents, only the versions with the indicated dates are applicable to this
document; for the undated referenced documents, only the latest version (including all
the amendments) is applicable to this document.
GB/T 176 Methods for chemical analysis of cement
GB/T 749 Test method for determining capability of resisting sulfate corrode of
cement
GB/T 750 Autoclave method for soundness of portland cement
GB/T 1346 Test methods for water requirement of normal consistency, setting time
and soundness of the portland cement
GB/T 5483 Natural gypsum
GB 6566 Limits of radionuclides in building materials
GB/T 8074 Testing method for specific surface of cement - Blaine method
GB/T 9774 Sacks for packing cement
GB/T 12573 Sampling method for cement
GB/T 17671 Test method of cement mortar strength (ISO method)
GB/T 21371 By-product gypsum used in cement
GB/T 26748 Cement grinding aids
GB 31893 Limit and determination of the water-soluble chromium (Ⅵ) content for
cement
3 Terms and definitions
The following terms and definitions apply to this document.
3.1 moderate sulfate resistance portland cement
A hydraulic material that is made from portland cement clinker with appropriate
composition, which is added with an appropriate amount of gypsum and then ground,
and can resist the erosion of medium mass concentration sulfate ions (≤2500 mg/L).
NOTE: Moderate sulfate resistance portland cement is referred to as moderate sulfate resistance cement,
and the code name is P.MSR.
3.2 high sulfate resistance portland cement
A hydraulic material that is made from portland cement clinker with appropriate
composition, which is added with an appropriate amount of gypsum and then ground,
and can resist the erosion of higher mass concentration sulfate ions ( >2500 mg/L and
≤8000 mg/L).
NOTE: High sulfate resistance portland cement is referred to as high sulfate resistance cement, and the
code name is P.HSR.
4 Materials
4.1 Clinker
The portland cement clinker, which is composed of appropriate ingredients, mainly
includes calcium silicate, and is obtained from burning the raw meal composed of
appropriate ingredients until it is partially melted.
4.2 Gypsum
4.2.1 Natural gypsum
It shall comply with the provisions of GB/T 5483.
4.2.2 Desulfurization gypsum
It shall comply with the provisions of GB/T 21371.
4.3 Cement grinding aids
Grinding aids are allowed to be added during cement grinding, and the amount added
shall not exceed 0.5% of the cement mass. Grinding aids shall comply with the
provisions of GB/T 26748.
5 Strength grade
The strength grade of moderate and high sulfate resistance cement is 42.5.
6 Technical requirements
6.1 Requirements for chemical composition
6.1.1 Magnesium oxide (MgO)
The content (mass fraction) of magnesium oxide is not more than 5.0%.
If the cement passes the autoclave method for soundness, the content (mass fraction) of
magnesium oxide in the cement does not exceed 6.0%.
6.1.2 Sulfur trioxide (SO3)
The content (mass fraction) of sulfur trioxide is not more than 2.5%.
6.1.3 Loss on ignition (LOI)
The loss on ignition (mass fraction) is not more than 3.0%.
6.1.4 Insoluble residue (IR)
The content (mass fraction) of insoluble residue is not more than 0.75%.
6.2 Water-soluble chromium (Ⅵ) in cement
Water-soluble chromium (Ⅵ) in cement shall meet the requirements of GB 31893.
6.3 Tricalcium silicate (C3S) and tricalcium aluminate (C3A)
The content of tricalcium silicate and tricalcium aluminate in cement shall meet the
requirements in Table 1.
6.6 Radioactivity
The specific activity of radioactivity shall meet the requirement that the internal
exposure index IRa is not greater than 1.0 and the external exposure index Ir is not greater
than 1.0.
7 Test method
7.1 Calcium oxide, silicon dioxide, aluminum oxide, ferric oxide, magnesium oxide,
sulfur trioxide, loss on ignition, insoluble residue, and alkali content
The tests shall be carried out according to GB/T 176. Among them, the alkali content is
calculated according to formula (1).
Alkali content = w(Na2O) + 0.658w(K2O) ……………………… (1)
where:
w(Na2O) -- the sodium oxide content in cement;
w(Na2O) -- the potassium oxide content in cement.
7.2 Water-soluble chromium (Ⅵ) in cement
The test is carried out according to GB 31893.
7.3 Tricalcium silicate and tricalcium aluminate
The tests are carried out according to Appendix A.
7.4 Specific surface area
The test is carried out according to GB/T 8074.
7.5 Setting time and boiling stability
The tests are carried out according to GB/T 1346.
7.6 Autoclave method for soundness
The test is carried out according to GB/T 750.
7.7 Strength
The test is carried out according to GB/T 17671.
7.8 Sulfate resistance
Type inspection items are 6.1, 6.2, 6.3, 6.5, and 6.6.
In one of the following situations, type inspection shall be carried out:
-- When a product is newly put into production;
-- When the raw fuel is changed; [Translator’s note: should be the raw material]
-- When the production process is changed;
-- When the product production resumes after 6 months of suspension;
During normal production, type inspection shall be carried out at least once a year.
Among them, 6.2 and 6.6 shall be carried out at least every six months.
8.3 Judgment rules
8.3.1 Factory inspection
If the test results conform to 6.1, 6.3, and 6.5, the product is qualified. If the inspection
result does not meet any of the technical requirements in 6.1, 6.3, and 6.5, the product
is unqualified.
8.3.2 Type inspection
If the test results conform to 6.1, 6.2, 6.3, 6.5, and 6.6, the product is qualified. If the
inspection result does not meet any of the technical requirements in 6.1, 6.2, 6.3, 6.5,
and 6.6, the product is unqualified.
8.4 Inspection report
The content of the inspection report shall include the executive standard, cement type,
code, strength grade, factory number, factory inspection items, water consumption for
standard consistency, types and dosage of gypsum and grinding aids, and other technical
requirements stipulated in the contra...