GB/T 14685-2022 English PDF (GBT14685-2022)

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GB/T 14685-2022: Pebble and crushed stone for construction
GB/T 14685-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 91.100.15
CCS Q 13
Replacing GB/T 14685-2011
Pebble and crushed stone for construction
ISSUED ON: APRIL 15, 2022
IMPLEMENTED ON: NOVEMBER 01, 2022
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 ... 6
4 Classifications and categories ... 8
5 General requirements ... 8
6 Technical requirements ... 8
7 Test methods ... 11
8 Inspection rules ... 48
9 Marking, storage, transportation ... 49
Pebble and crushed stone for construction
1 Scope
This document stipulates the classification and categories, general requirements,
technical requirements, test methods, inspection rules, marking, storage, transportation
of pebbles and crushed stone used for construction.
This document applies to pebbles and crushed stone, which are used in cement concrete
and its products in construction projects (except hydraulic buildings).
2 Normative references
The contents of the following documents constitute essential provisions of this
document through normative references in the text. Among them, for dated reference
documents, only the version corresponding to the date applies to this document; for
undated reference documents, the latest version (including all amendments) applies to
this document.
GB 175 Common Portland cement
GB/T 2419 Test method for fluidity of cement mortar
GB/T 6003.1 Test sieves - Technical requirements and testing - Part 1: Test sieves
of metal wire cloth
GB/T 6003.2 Test sieves - Technical requirements and testing - Part 2: Test sieves
of perforated metal plate
GB 6566 Limits of radionuclides in building materials
GB 8076-2008 Concrete admixtures
GB/T 14684-2022 Sand for construction
GB/T 17671 Test method of cement mortar strength (ISO method)
SL/T 352-2020 Test code for hydraulic concrete
3 Terms and definitions
The following terms and definitions apply to this document.
7.3.2.2 Weigh the specimen according to the provisions of Table 11. Pour the specimen
onto a set of sieves (with sieve bottom), which are assembled from top to bottom,
according to the hole size. Then sieve.
7.3.2.3 Place the sieve set on the sieve shaker, to shake the sieve for 10 minutes.
Remove the sieve set and sieve by hand one by one, according to the size of the sieve
holes, until the throughput per minute is less than 0.1% of the total specimen mass. The
particles that have passed are merged into the next sieve, which are sieved together with
the specimen in the next sieve. In this order, make it pass all sieves. When the particle
size of the remaining particles is greater than 19.0 mm, it is allowed to use fingers to
stir the particles during the screening process.
7.3.2.4 Weigh out the screening residue of each size sieve.
7.3.3 Result calculation and evaluation
7.3.3.1 Calculate the sub-calculated screening residue percentage: The ratio of the
screening residue of each size sieve to the total mass of the specimen, which shall be
accurate to 0.1%.
7.3.3.2 Calculate the cumulative screening residue percentage: The sum of the sub-
calculated screening residue percentages of this sieve and above sieves, which shall be
accurate to 1%. After screening, if the difference -- between the sum of the screening
residue of each sieve and the screening residue at the bottom of the sieve and the mass
of the specimen before screening -- exceeds 1%, the test shall be performed again.
7.3.3.3 Evaluate the particle gradation of the specimen, based on the cumulative
screening residue percentage of each size sieve.
7.4 Clay content in pebble and clay content and fine content in crushed stone
7.4.1 Instruments and equipment
Instruments and equipment shall meet the following requirements:
a) Oven: Temperature controlled at (105 ± 5) °C;
b) Balance: The graduation value is not greater than 0.1% of the minimum specimen
mass;
c) Test sieve: A square hole sieve, which has hole diameter of 75 μm and 1.18 mm;
d) Container: When washing the specimen, keep the specimen from splashing;
e) Shallow plate: Porcelain or metal.
7.4.2 Test procedures
ma1 - The mass of the dried specimen before the test, in grams (g);
ma2 - The mass of the dried specimen after the test, in grams (g).
7.4.3.2 The clay content in pebbles and clay content and fine content in crushed stone
shall be the arithmetic mean of the two test results, accurate to 0.1%. When the
difference between the two results exceeds 0.2%, it shall take sample again for the
testing.
7.5 Clay lumps and friable particles content
7.5.1 Instruments and equipment
Instruments and equipment shall meet the following requirements:
a) Oven: Temperature controlled at (105 ± 5) °C;
b) Balance: The graduation value is not greater than 0.1% of the minimum specimen
mass;
c) Test sieve: Square hole sieve, which has hole diameter of 2.36 mm and 4.75 mm;
d) Container: When washing the specimen, keep the specimen from splashing;
e) Shallow plate: Porcelain or metal.
7.5.2 Test procedures
The single particle size of 5 mm ~ 10 mm shall be processed according to the method
specified in 7.6 of GB/T 14684-2022. The following steps shall be followed for other
particle sizes:
a) Take samples according to the provisions of 7.1. Reduce the specimen to no less
than 2 times the mass specified in Table 12. Place it in an oven, to dry it to constant
weight at (105 ± 5) °C. After cooling to room temperature, screen out the particles
smaller than 4.75 mm. Divide it into two equal parts for later use;
b) Weigh a portion of the specimen (mb1). Pour the specimen into the elutriation
container. Inject clean water, so that the water level is higher than the upper
surface of the specimen. Stir thoroughly. Soak (24 ± 0.5) hours. Then crush the
mud block in water. Then place the specimen on a 2.36 mm sieve. Wash with
water, until the water in the container is clear by visual inspection;
c) Take out all the retained specimen from the sieve. Put them into a shallow plate.
Dry them in an oven at (105 ± 5) °C to a constant weight. After cooling to room
temperature, weigh their mass (mb2).
7.5.3 Result calculation and evaluation
a) Reagents: Sodium hydroxide, tannic acid, ethanol, distilled water;
b) Sodium hydroxide solution: Dissolve 3 g of sodium hydroxide in 97 mL distilled
water;
c) Standard solution: Dissolve 2 g of tannic acid in 98 mL of ethanol solution (10
mL of absolute ethanol plus 90 mL of distilled water), to obtain a tannic acid
solution. Then take 25 mL of this solution. Inject it into 975 mL of sodium
hydroxide solution. Add a stopper. Shake vigorously. Let stand for 24 h, to obtain
the standard solution.
7.8.2 Instruments and equipment
Instruments and equipment shall meet the following requirements:
a) Balance: The measuring range is not less than 2 kg, the graduation value is not
more than 2 g. The measuring range is not less than 100 g, the graduation value
is not more than 0.1 g;
b) Graduated cylinder: 100 mL, the graduation value is not more than 1 mL; 1000
mL, the graduation value is not greater than 5 mL;
c) Test sieve: A square hole sieve, which has a hole diameter of 19.0 mm;
d) Beaker, glass rod, pipette, etc.
7.8.3 Test procedures
7.8.3.1 Take samples according to the provisions of 7.1. Screen out particles la...