GB/T 8077-2023 Methods for testing uniformity of concrete admixtures
1 Scope
This document describes the methods for testing uniformity of concrete admixtures.
This document is applicable to high performance water reducing admixture, high efficiency water reducing admixture, normal water reducing admixture, air entraining type water reducing admixture, pumping agent, early strength agent, retarder, air-entraining agent, waterproofing agent, antifreeze, flash setting admixture and expansive agent, etc.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 175 Common portland cement
GB/T 2419 Test method for fluidity of cement mortar
GB/T 6005 Test sieves - Metal wire cloth, perforated metal plate and electroformed sheet - Nominal sizes of openings
GB/T 6682-2008 Water for analytical laboratory use - Specification and test methods
GB/T 8075-2017 Terms of concrete admixtures
GB/T 17671 Test method of cement mortar strength (ISO method)
JC/T 681 Mixer for mixing mortars
JC/T 729 Mixer for cement paste
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 8075-2017 and the following apply.
3.1
repeatability conditions
independent testing conditions on the same test object in a short period of time in the same laboratory with the same equipment by the same operator according to the same testing method
[Source: GB/T 8075-2017, 6.7]
3.2
reproducibility conditions
independent testing conditions on the same test object in different laboratories with the different equipment by the different operators according to the same testing method
[Source: GB/T 8075-2017, 6.8]
3.3
repeatability limit
value delimiting a probability of 95% that the absolute difference of two test results is less than or equal to it under the repeatability conditions (3.1)
[Source: GB/T 3358.2-2009, 3.3.9]
3.4
reproducibility limit
value delimiting a probability of 95% that the absolute difference of two test results is less than or equal to it under the reproducibility conditions (3.2)
[Source: GB/T 3358.2-2009, 3.3.14]
4 Test conditions
4.1 Number of tests and requirements
4.1.1 The number of tests for determination of each chemical property shall be two. The absolute difference between the two results shall be within the repeatability limit. The mean of the two test results shall be used to express the test result. If the absolute difference between the two results exceeds the repeatability limit, it is necessary to carry out the third determination in a short time, eliminate the data exceeding the repeatability limit, and take the mean of the other two data. If the third data is within the two values, the mean of the three test results shall be used to express the test result. Unless otherwise specified, if the deviations of three results all exceed the repeatability limit, the test shall be conducted again.
4.1.2 During routine production control analysis, determination of each chemical property by a single test shall be the minimum required.
4.1.3 The water used in this document shall not be lower than the requirements of Grade III water specified in GB/T 6682-2008, except the fluidity of cement paste and the water-reducing rate of cement mortar.
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Foreword III
1 Scope
2 Normative references
3 Terms and definitions
4 Test conditions
4.1 Number of tests and requirements
4.2 Blank test
4.3 Ignition
4.4 Constant mass
4.5 Inspection of chloride ions (Cl-) (with silver nitrate solution)
4.6 Requirements for reagents
4.7 Requirements for data processing
5 Appearance
6 Stability
6.1 Principle
6.2 Instruments
6.3 Test procedure
6.4 Calculation and expression of results
6.5 Determination of test results
7 Solid content
7.1 Drying method
7.2 Dilution drying method
7.3 Vacuum drying method
8 Moisture content
8.1 Drying method
8.2 Vacuum drying method
9 Density
9.1 Pyknometer method
9.2 Precision densitometer method
10 Fineness
10.1 Hand sieving method
10.2 Negative pressure sieve method
11 pH
11.1 Principle
11.2 Instruments
11.3 Test conditions
11.4 Test procedure
11.5 Expression of results
11.6 Repeatability limit and reproducibility limit
12 Surface tension
12.1 Principle
12.2 Instruments
12.3 Test conditions
12.4 Test procedure
12.5 Result and calculation
12.6 Repeatability limit and reproducibility limit
13 Chloride ion content
13.1 Potentiometric titration
13.2 Ion chromatography
14 Sodium sulfate content
14.1 Gravimetric method
14.2 Ion exchange gravimetric method
15 Fluidity of cement paste
15.1 Principle
15.2 Materials and instruments
15.3 Environmental conditions
15.4 Test procedure
15.5 Expression of results
15.6 Repeatability limit and reproducibility limit
16 Water reducing rate of cement mortar
16.1 Principle
16.2 Materials and instruments
16.3 Environmental conditions
16.4 Test procedure
16.5 Result and calculation
16.6 Repeatability limit and reproducibility limit
17 Alkali content
17.1 Flame photometry
17.2 Atomic absorption spectrophotometry
Annex A (Informative) Effective composition
A.1 Principle
A.2 Reagents and instruments
A.3 Environmental conditions
A.4 Test procedure
Annex B (Informative) Corresponding relationship between density of pure water and temperature
Annex C (Informative) Example of calculating chloride ion percentage in concrete admixture by the second derivative method
C.1 Blank test and calibration of silver nitrate concentration
C.2 Test of admixture sample
Bibliography
