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GB/T 1345-2005The test sieving method for fineness of cement (English PDF)

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Issued by

General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China

Level / Type

National · Recommended

Issue date

January 19, 2005

Implementation date

August 1, 2005

Scope

GB/T 1345-2005 (The test sieving method for fineness of cement) is available as an English-translated PDF.

GB/T 1345-2005 — This Standard specifies the sieving method for fineness of cement by 45 µm square-aperture standard sieves and 80 µm square-aperture standard sieves.

This Standard applies to Portland cement, ordinary Portland cement, slag Portland cement, pozzolanic Portland cement, fly ash Portland cement, composite Portland cement, and other types of cement and powdery materials designated to use this Standard.

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Document preview — GB/T 1345-2005

National Standard of the People's Republic of China

ICS: 91.100.10
Classification: Q 11

Issued by: General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China

Foreword...3
1 Scope...5
2 Normative references...5
3 Method principle...5
4 Terms and definitions...6
5 Instruments...6
6 Sample requirements...9
7 Operating procedures...9
8 Results calculation and processing...11
Annex A (normative) Calibration method for cement test sieves...13

Foreword

This Standard refers to ASTM C786-96 "Standard Test Method for Fineness of

Hydraulic Cement and Raw Materials by the 300 µm (No. 50), 150 µm (No.

100), and 75 µm (No. 200) Sieves by Wet Methods", ISO/DIS/10749 "Methods

of testing cement - Determination of fineness" and BS EN196-6.2000 "Methods

of testing cement - Part 6.Determination of fineness".

This Standard replaces GB/T 1345-1991 "Test method for fineness of cement -

The 80 µm sieve" from the date of its implementation.

Compared with GB/T 1345-1991, the changes are as follows.

- The standard name is changed to "The test sieving method for fineness of

cement" (the standard name of 1991 edition; Clause 4 of this edition);

- ADD square-aperture sieves with an aperture size of 45 µm (see Clause 1

of this edition);

- ADD the terms and definitions (see Clause 4 of this edition);

- ADD the provisions for sample requirements (see Clause 6 of this edition);

- ADD the requirement that "in the qualification test, the average value of the

parallel results of two samples is used as the sieving result of the sample

instead of the determined value of one sample" (see subclause 8.3 of this

edition);

- ADD the provisions for cleaning and calibration of test sieves (see Clause

7.5 and Annex A of this edition).

Annex A of this Standard is a normative annex.

This Standard was proposed by China Building Materials Academy.

This Standard shall be under the jurisdiction of National Technical Committee

on Cement of Standardization Administration of China.

Drafting organization of this Standard. China Building Materials Academy.

Participating drafting organizations of this Standard. Zhejiang Shaoxing Taoyan

Xinxing Instrument Factory, Shaanxi Xi'an Cable & Copper Mesh Factory.

Main drafters of this Standard. Chen Ping, Zhang Datong, Yan Bilan, Xi Jinsong,

Tao Baorong, Zhang Xiqiang.

The previous released versions replaced by this Standard are as follows.

- GB 1345-1962, GB 1345-1977, GB/T 1345-1991.

The test sieving method for fineness of cement

1 Scope

This Standard specifies the sieving method for fineness of cement by 45 µm

square-aperture standard sieves and 80 µm square-aperture standard sieves.

This Standard applies to Portland cement, ordinary Portland cement, slag

Portland cement, pozzolanic Portland cement, fly ash Portland cement,

composite Portland cement, and other types of cement and powdery materials

designated to use this Standard.

2 Normative references

The following documents contain the provisions which, through reference in this

Standard, become the provisions of this Standard. For dated references, their

subsequent amendments (excluding corrigendum) or revisions do not apply to

this Standard. However, the parties who enter into agreement based on this

Standard are encouraged to investigate whether the latest versions of these

documents are applicable. For undated reference documents, the latest

versions apply to this Standard.

GB/T 5329 Test sieves and test sieving - Vocabulary

GB/T 6003.1 Test sieves of metal wire cloth

3 Method principle

This Standard uses 45 µm square-aperture sieves and 80 µm square-aperture

sieves to perform the sieving test on cement samples. The mass percentage of

the sieve residue on the sieve is used to represent the fineness of the cement

sample.

4 Terms and definitions

This Standard uses GB/T 5329 and the following terms and definitions.

4.1

vacuum sieving

Using a vacuum sieving analyzer to sieve the cement in the test sieve within a

specified sieving time by the constant air flow generated by the negative

pressure source.

5 Instruments

5.1 Test sieve

5.2 Vacuum sieving analyzer

5.2.1 A vacuum sieving analyzer consists of a sieve base, a vacuum sieve, a

negative pressure source and a dust collector, where the sieve base consists

of an air jet nozzle with a rotation speed of 30 r/min ± 2 r/min, a negative

pressure meter, a control board, a micro motor and a shell, see Figure 3.

5.2.2 The adjustable range of the negative pressure of sieving analyzers is

4000 Pa ~ 6000 Pa.

5.2.3 The distance between the upper opening plane of the air jet nozzle and

the sieving medium is 2 mm ~ 8 mm.

5.2.4 The dimensions of the upper opening of the air jet nozzle is shown in

Figure 4.

5.2.5 Negative pressure source and dust collector, consisting of an industrial

vacuum cleaner with a power of >= 600 W and a small cyclone dust collector or

other equipment with equivalent functions.

6 Sample requirements

Cement samples shall be representative. The sample processing method is in

accordance with Clause 3.5 of GB 12573-1990.

7 Operating procedures

7.1 Test preparation

The test sieve used before the test shall be kept clean, and the vacuum sieve

and manual sieve shall be kept dry. During the test, it weighs 25 g of sample

for 80 µm sieve tests and weighs 10 g of sample for 45 µm sieve tests.

7.2 Vacuum sieving

7.2.1 Before the sieving test, PLACE the vacuum sieve on the sieve base,

COVER the sieve cover, CONNECT to the power supply, CHECK the control

system, and ADJUST the negative pressure to the range of 4000 Pa to 6000

Pa.

7.3 Wet sieving

7.3.1 Before the sieving test, CHECK that there is no mud or sand in the water,

ADJUST the water pressure and position of the wet sieve holder so that it can

operate normally, and CONTROL the distance between the bottom surface of

the nozzle and the sieving medium to 35 mm ~ 75 mm.

7.4 Manual sieving

7.4.1 WEIGH the cement sample to the nearest 0.01 g and POUR it into a

manual sieve.

7.4.2 USE one hand to hold the sieve and shake back and forth, and gently tap

with the other hand. The reciprocating shaking and tapping process shall be

kept close to horizontal.

7.5 For other powdery materials or sieving tests using square-aperture sieves

other than 45 µm to 80 µm, the relevant parameters such as the size of the

sieve, the sample amount and the sieving time shall be specified.

7.6 Cleaning of test sieve

The test sieve must always be kept clean. The sieve aperture shall be clear. It

shall be cleaned after being used for 10 times.

8 Results calculation and processing

8.1 Calculation

The percentage sieve residue of the cement sample is calculated as follows.

8.2 Correction of sieve residue results

The sieving medium of the test sieve will wear during the test, so the sieving

result shall be corrected. The correction method is to multiply the result of 8.1

by the effective correction factor obtained after the test sieve is calibrated

according to Annex A, which is the final result.

Annex A

(normative)

Calibration method for cement test sieves

A.1 Scope

The method specified in this annex is applicable to the calibration of cement

test sieves.

A.2 Principle

The ratio of the determined value of the standard sample on the test sieve to

the standard value of the standard sample is used to reflect the accuracy of the

aperture of the test sieve.

A.3 Test conditions

A.3.1 Standard sample of cement fineness

A standard sample that meets the requirements of GSB 14-1511, or of the same

grade. In case of dispute, the GSB 14-1511 standard sample shall prevail.

A.3.2 Instruments and equipment

Corresponding equipment that meets the requirements of Clause 5 of this

Standard.

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 13 pages — is available in the English PDF.

Referenced standards

Normative references

GB/T 6003.1Test sieves—Technical requirements and testing—Part 1:Test sieves of metal wire cloth

GB/T 5329

Cited by

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