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This standard is revised on the basis of GB/T 14685—1993, pebble and crushed stone resources, as well as production change and development, with reference to relevant standards of ISO, Europe, America, Britain and Japan since 1990s.The key technical indexes shall be revised closing to the international advanced standards for international communication on condition that meeting the national conditions.
There have been some significant changes in this national standard over GB/T 14685—1993 in the following aspects:
1. The sieve meshes of pebble and crushed stone sieves are changed to square according to the requirements of the international standard ISO 6274; some aperture and few screen residue index indexes are revised;
2. The classification of products is revised;
3. Silt content, clay lump, elongated flaky particle content, chlorides, crushed stone crushing index, loose stacking density, some definitions and technical requirements are revised;
4. Some requirements in the test methods are improved; quick test for alkali-aggregate reaction and alkali-carbonate reaction test method are added.
This standard will be implemented from February 1, 2002 and shall replace GB/T 14685—1993 simultaneously.
According to the requirements of the engineering, if the water absorption, water ratio and surface water ratio of pebbles and crushed stones shall be measured, they shall be carried out according to Annex B and Annex C.
Annex A in this standard is normative. Annex B and Annex C are informative.
This standard was proposed by the State Bureau of Building Materials Industry.
Drafting organization: China Sand Stone Association
Participating development organizations: Beijing Building Material Industry Management Office, Beijing University of Civil Engineering and Architecture, Beijing Building Materials Quality Supervision Test Center, Nordberg Beijing Office, Beijing Sanlian Concrete Co., Ltd., Shanghai Building Materials and Members Quality Supervision Test Center, Shanghai Construction Road and Bridge Mechanical Equipment Co., Ltd., Tianjin CSR Concrete Company Jixian Quarry, Ningbo (Zhejiang) Local Building Material Management Office, Huzhou (Zhejiang) Xinkaiyuan Crushed Stone Co., Ltd. (Shanghai Construction Engineering Materials Company), Hangzhou Zhangshan Mountain Quarry, Guangzhou Jiahua (Huangpi) Quarry, Huiji Group Hongli Quarry, Fujian Standard Sand Factory, Shangqiu Artificial Sand Seminar, China Architectural Research and Design Institutes of Guizhou.
Chief drafting staffs of this standard: Chen Jialong, Yang Yongqi, Yao Lijun, Zhang Guomin, Qiao Jike, Qiu Qin, Liu Weichao, Gao Wei.
This standard was issued in 1993 for the first time.
China Sand Stone Association is in charge of the explanation of this standard.
National Standard of the People's Republic of China
Pebble and Crushed Stone for Building
1 Scope
This standard specifies the definitions, classification and specification, technical requirements, test methods, inspection rules, symbol, storage and transportation of pebble and crushed stone for building.
This standard is applicable to the pebbles and crushed stones for cement concrete and its products in the constructional engineering; those for other engineering may also be carried out according to this standard.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below.
GB 175—1999 Portland Cement and Ordinary Portland Cement
GB/T 177—1985 Method of testing cements—Determination of strength
GB/T 2419—1994 Test method for fluidity of cement mortar
GB/T 6003.1—1997 Test sieves of metal wire cloth (eqv ISO3310-1:1990)
GB/T 6003.2—1997 Test sieves of perforated metal plate (eqv ISO3310-2:1990)
3 Definitions
This standard adopts the following definitions.
3.1 Pebble
Rock particles, particle size larger than 4.75mm, formed through natural weathering, potamic transport, sorting and stacking.
3.2 Crushed stone
Rock particles, particle size larger than 4.75mm, formed through mechanical disruption and screening of natural rock or pebble.
3.3 Elongated flaky particle
Elongated particles are those pebble and crushed stone particles whose length is larger than 2.4 times of the average particle diameter of the corresponding size fraction; flaky particles are those whose thickness is less than 0.4 times of the average particle diameter (average particle diameter refers to the average value of the upper and lower limit particle size).
3.4 Silt content
Material finer than 75 μm in pebble and crushed stone
3.5 Clay lump
Contents of particles in the pebble and crushed stone whose original particle size is larger than 4.75mm, and less than 2.36mm after immersion cleaning with water and squeezing with hands
3.6 Soundness
The ability of pebble and crushed stone to resist fracture under the action of natural weathering and other external physicochemical factors
3.7 Alkali-aggregate reaction
Expansion reaction of concrete components such as concrete and admixture, alkali in the environment, as well as alkali active mineral in the aggregate occurring slowly in the humid environment and resulting in concrete cracking damage.
4 Classification and Specification
4.1 Classification
a) Pebble;
b) Crushed stone.
4.2 Specification
They can be divided into single size fraction and continuous size fraction according to the particle size dimensions of pebble and crushed stone Pebble and crushed stone with particular size fractions can be mixed with different single size fraction pebbles and crushed stones as required.
4.3 Type
They can be divided into Type I, Type II and Type III according to the technical requirements of pebble and crushed stone.
4.4 Purpose
Type I should be used in the concrete with larger than C60 strength grade. Type II should be used in the concrete with C30~ C60 strength grade, or with anti-freezing, impervious or other requirements. Type Ⅲ should be used in the concrete with less than C30 strength grade.
5 Technical Requirements
5.1 Grain composition
The grain composition of pebble and crushed stone shall meet the requirements of Table 1.
Foreword
1 Scope
2 Normative References
3 Definitions
4 Classification and Specification
5 Technical Requirements
6 Test Methods
7 Inspection Rules
8 Mark, Storage and Transportation
Annex A (Normative) Aggregate Alkali Reactivity Inspection (Lithofacies Method)
Annex B (Informative) Determination of Water Absorption
Annex C (Informative) Determination of Water Content Ratio and Surface Water Content Ratio
