GB/T 14684-2022Sand for construction (English PDF)

4.1 Classification

4.1.1 According to the source, it is divided into natural sand, manufactured sand, mixed sand.

4.1.2 According to the fineness modulus, it is divided into coarse sand, medium sand, fine sand, extra fine sand. The fineness modulus are as follows: - Coarse sand. 3.7 ~ 3.1; - Medium sand. 3.0 ~ 2.3; - Fine sand. 2.2 ~ 1.6; - Extra fine sand. 1.5 ~ 0.7.

4.2 Category Construction sand is divided into category I, category II, category III, based on particle gradation, clay content (fine content), methylene blue (MB) value, clay lumps and friable particles content, hazardous substances, soundness, crushing index, flake particle content technical requirements.

6.1 Particle gradation

6.1.1 Except for extra-fine sand, the cumulative screening residue of category I sand shall comply with the requirements of Zone 2 in Table 1; the sub-calculated screening residue shall comply with the requirements of Table

2.The cumulative screening residue of category II and category III sand shall comply with the requirements of Table

7.1 Specimen

7.1.1 Number of specimens The minimum sampling mass for a single test shall comply with the requirements in Table

9.If several tests are performed, the same specimen can be used for several different tests, if it can be ensured that the specimen will not affect the results of another test.

7.1.2 Sampling method

7.1.2.1 Take samples according to the quantity specified in 7.1.1.

7.1.2.2 When sampling on the material pile, the sampling parts shall be evenly distributed. Before sampling, remove the surface layer of the sampling location; then randomly select 8 roughly equal sets of sand from different locations, to form a set of samples.

7.1.2.3 When sampling from the belt conveyor, it shall randomly take 4 roughly equal sets of sand from the full-section, to form a set of samples.

7.1.2.4 When sampling from trains, trucks, cargo ships, randomly select 8 roughly equal sets of sand from different locations and depths, to form a set of samples.

7.1.3 Specimen treatment

7.1.3.1 Use the distributor method. Stir the sample evenly in a moist state. Then pass it through the distributor. Take one set of sample from the hopper; pass it through the distributor again. Repeat the above process, until the sample is reduced to the required amount for the test.

7.1.3.2 Manual quartering method. Place the sample taken on a flat plate. Mix evenly in a moist state. Pile it into a round cake, which has a thickness of about 20 mm. Then divide the round cake into 4 equal parts, along two mutually perpendicular diameters. Take 2 diagonal sets. Mix them thoroughly. Then pile them into a round cake. Repeat the above process, until the sample is reduced to the required amount for the test.

7.1.3.3 The samples used in the bulk density and manufactured sand soundness tests can be tested directly, after being mixed evenly, without being reduced.

7.2 Test environment The temperature of the laboratory shall be maintained at (20 ± 5) °C.

7.3 Particle gradation

7.3.1 Instruments and equipment Instruments and equipment shall meet the following requirements.

a) Oven. Temperature controlled at (105 ± 5) °C;

b) Balance. The measuring range is not less than 1000 g; the graduation value is not more than 1 g;

c) Test sieve. The sieves which have specifications of

0.15 mm,

0.30 mm,

0.60 mm,

9.50 mm; have sieve bottom and sieve cover; comply with the provisions for square hole test sieves in GB/T 6003.1 and GB/T 6003.2;

d) Sieve shaker.

7.3.2.1 Take samples according to the provisions of 7.1.Screen out particles larger than

9.50 mm. Calculate the screening residue percentage. Reduce the specimen to about 1100 g. Dry it in an oven at (105 ± 5) °C, until it reaches constant weight. After cooling to room temperature, divide it into 2 equal portions, to prepare for use.

Note. Constant weight means that when the interval between two adjacent weighing is not less than 3 hours, the difference in mass between the two is not greater than the weighing accuracy required for the test (the same below).

7.3.2.2 Weigh 500 g of specimen, accurate to 1 g. 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 it.

7.3.2.3 Place the sieve set on the sieve shaker. Shake the sieve for 10 minutes. Remove the sieve set. Sieve it 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 volume. The passed specimens are merged into the next No. of sieve, which is passed the next No. of sieve together the specimen in it. Proceed in this order, until all sieves are finished. Weigh out the screening residue of each No. of sieve, accurate to 1 g.

7.3.2.4 The screening residue (ma) of the specimen on each No. of sieve shall not exceed the value, which is calculated according to formula (1).

7.3.3 Result calculation

7.3.3.1 Calculate the sub-calculated screening residue percentage. The ratio of the screening residue of each No. of sieve to the total amount of the specimen. The calculation is accurate to 0.1%.

7.3.3.2 Calculate the cumulative screening residue percentage. The sub-calculated screening residue percentage of the sieve No. plus the sum of all sub-calculated screening residue percentages of this No. of sieve, accurate to 0.1%. After screening, when the difference -- BETWEEN the sum of the screening residue of each No. of sieve and the residue at the bottom of the sieve AND the mass of the original specimen -- exceeds 1%, the test shall be performed again.

7.3.3.3 The fineness modulus of sand shall be calculated according to formula (2), accurate to 0.01.

7.4 Clay content

7.4.1 Instruments and equipment Instruments and equipment shall meet the following requirements.

a) Oven. Temperature is controlled at (105 ± 5) °C;

b) Balance. The measuring range is not less than 1000 g; the graduation value is not more than

0.1 g;

c) Test sieve. A square hole sieve, which has a hole diameter of 75 µm and

d) Container. The depth is greater than 250 mm; the specimen shall be kept from splashing when washing the specimen.

8.1.1 Exit-factory inspection

8.1.1.1 The exit-factory inspection items of natural sand shall be. particle gradation (including fineness modulus), clay content, clay lumps and friable particles content, mica content, loose stacking density. The exit-factory inspection items of purified sea sand shall also include chloride content and shell content.

8.1.1.2 The exit-factory inspection items of manufactured sand shall be. particle gradation (including fineness modulus), methylene blue value and fine content, clay lumps and friable particles content, crushing indicator, loose stacking density. The exit- factory inspection items for category I manufactured sand shall also include the content of flaky particles in manufactured sand.

8.1.2 Type inspection Type inspection shall be carried out under any of the following circumstances.

a) When new products are put into production;

b) When the source of raw materials or production process changes;

c) Once a year during normal production;

d) When production is resumed after a long-term suspension;

e) When there is a big difference between the exit-factory inspection results and the type inspection.