Some standard content:
People's Republic of China
National Standard
Standard Sand for Cement Strength Test
GB 178-77
Replaces GB178-62
Standard sand is a material used to uniformly test cement strength. It is made from natural quartz sea sand from Luyangpu, Pingtan County, Fujian Province, after screening and washing. Quality indicators
1. Silicon dioxide (SiO.》 content is greater than 98%. 2. Loss on ignition shall not exceed 0.40%.
3. Mud content (including soluble salts) shall not exceed 0.20%. 4. Particle size (see the table below):
Square hole sieve
Diameter, mm
II. Trial finishing method
5. Determination of silicon dioxide and loss on ignition shall be carried out according to Appendix 1. 6. Determination of mud content and particle size shall be carried out according to Appendix 2. III. Acceptance planning
System sieve residue%
40 ±5
7. Standard sand is numbered for each ton shipped out of the factory. Three representative samples should be taken for each number, and the particle size should be measured separately. The measurement results must meet the requirements.
8. Any product that does not meet any of the requirements in Chapter 1 of this standard shall not be shipped out of the factory. Round, package and storage and transportation
9. The packaging bag should be firm and sturdy, with a net weight of 25 kg per package. A certificate of conformity must be attached to the bag, indicating the production date and number. Prevent moisture and leakage during storage and transportation.
Published by the National Standard Metrology Island
Proposed by the State Administration of Building Materials Industry
Implementation on July 1, 1979
Drafted by the Building Materials Science Research Institute
GB 178—77
Chemical analysis method for silicon dioxide and loss on ignition 1. General
1. This method is applicable to standard sand for cement strength test and various quartz sands that are allowed to be tested with this standard method. 2. When weighing the sample, weigh to 0.0002 grams. The dosage of reagents and the analysis steps should be strictly carried out in accordance with the provisions of this method. 3. The water used for chemical analysis should be distilled water or ion exchange water, and the reagents used should be analytically pure or guaranteed reagents. If there is any doubt about the water or reagents used, they should be identified.
. When conducting chemical analysis, the weight of the balance used should be calibrated, and the sensitivity of the balance should be 0.0002 grams. 5. The fixed tube used in this method should be calibrated. 6. A blank test must be performed for the traceability of silicon dioxide. 2. Analytical samples||tt| |7. The sample sent to the inspection room shall not be less than 200 grams. It should be placed in a wide-mouthed glass bottle with a ground stopper. During the inspection, the sample is mixed and evenly reduced to 25 grams by quartering, then placed in an agate mortar and ground until all of it passes through a square hole sieve with a hole diameter of 0.080 mm. The ground standard sand is placed in a small wide-mouthed glass bottle with a ground stopper and placed in an oven at 105-110℃ (the bottle mouth should be spread) for one hour. Then take it out, cover it, and place it in a desiccator to cool to room temperature. Wait for analysis. III. Test method
Determination of egg loss on burning
Accurately weigh about 1 gram of the sample, put it in a porcelain or platinum glass that has been burned to constant weight, place the lid obliquely on the glass, start heating from room temperature, burn at a high temperature of 950-1000℃ for 15-30 minutes, and weigh it after cooling. Then repeat the burning under high humidity. Cool and weigh until constant weight is reached.
Loss on ignition L, % is calculated as follows:
LG-GL×100
Wherein, L～—loss on ignition, %
G-—weight of the sample before ignition, g,
G,—weight of the sample after ignition, g.
9. Determination of silicon dioxide
(1) Reagents
a, potassium hydroxide, analytical grade,
b. Sodium hydroxide, analytical grade,
c. Potassium chloride, analytical grade,
d. Potassium chloride, analytical grade, www.bzxz.net
e, potassium hydrogen phthalate, standard reagent,
f, nitric acid, specific gravity 1.42, analytical grade
g. Nitric acid, 1:1,
h.95% ethanol, analytical grade
i.15% potassium fluoride solution: 15 grams of potassium fluoride (KF·2H,O) dissolved in 100 ml of wateri.5% potassium fluoride solution: 5 grams of potassium fluoride (KF·2H,0) dissolved in 100 ml of waterk, 5% potassium chloride-50% ethanol solution, dissolve 10 grams of potassium chloride in 100 ml of water, add 100 ml of ethanol, shake well, 1, 1% phenolic acid, 1 gram of phenolic acid dissolved in 100 ml of ethanol, GB 178-77
Ⅱ. Sodium hydroxide is dissolved in 10 liters of freshly boiled cold steamed water, then put it in a plastic bottle and shake it well. Install a soda lime drying tube on the top. For calibration, accurately weigh about 2 grams of potassium hydrogen phthalate into a 400 ml beaker, add about 50 ml of distilled water (freshly boiled and cooled to room temperature, neutralized by adding two drops of 1% phenol anhydride per 100 ml of distilled water, neutralized with sodium hydroxide standard solution to a slightly reddish color, and titrated with sodium hydroxide standard solution to a slightly reddish color. The clarity of sodium hydroxide standard solution to silicon dioxide, T, is calculated in mg/ml according to the following formula. T=e×0.01502×1000
Where: T is the number of milligrams of silicon dioxide equivalent to each milliliter of sodium hydroxide standard solution, g,
V is the amount of sodium hydroxide standard solution, ml, 0.01502 is the milligram equivalent of silicon dioxide, 0.2042 is the milligram equivalent of potassium hydrogen phthalate. ( 2) Analysis steps
Accurately weigh 0.1~0.15g of the sample in a bowl, add 3g of potassium hydroxide, cover, melt on a 500~600℃ electric furnace for 15~20 minutes until transparent, take out, and cool to room temperature. Add about 10ml of warm water to diffuse the molten block, and after it is completely dissolved, transfer it to a 300ml plastic cup, wash the crucible with a small amount of 1:1 nitric acid (note that the volume of taking and washing should not exceed 50ml), add 10ml of 15% potassium oxide solution, stir, add 15ml of nitric acid, stir and cool to room temperature, add solid potassium chloride to saturation (a small amount of potassium chloride solid will no longer dissolve). After standing for 10 minutes (wait for the precipitate to drop), filter with qualitative latent paper, wash the plastic cup twice with 6% potassium fluoride solution, and wash the precipitate once. Put it back into the original plastic cup, add 10 liters of 5% potassium hydroxide-50% ethanol solution and 1 ml of phenol solution, and neutralize with sodium hydroxide standard solution until it turns red. Add 200 ml of neutralized boiling water, and immediately titrate with the prepared sodium hydroxide standard solution until it turns slightly red. The silicon dioxide content X, % is calculated according to the following formula, X=TV
Wherein, T-the number of grams of silicon dioxide per milliliter of sodium hydroxide standard solution, V-the volume of sodium hydroxide standard solution consumed, liter G-the weight of the sample, mg.
Naijing II
1. Determination of mud content
GB178-77
Test method for main mud content and particle size
Dry the reduced sample at 105-110°C to constant weight. After cooling, weigh 100 grams , weigh to 0.1 g, pour into a glass container, and fill with clean water. Stir with a glass rod equipped with a rubber head for about 1 minute, carefully pour out the turbid water, and replace it with clean water. Repeat this process until the weighed water is clean and transparent. Wash it with distilled water again. Dry the sample to constant weight, cool and weigh it, and the mud content is calculated according to the following formula:
G-GL×100
Where: C—mud content, %,
G—weight of sample before washing, g,
G,—weight of sample after washing, g.
2. Particle size determination
Weigh 100 grams of the reduced sample and pour it into a test sieve with a square hole diameter of 0.65, 0.40 and 0.25 mm for sieving, until no more than 0.5 grams pass through per minute. Calculate the cumulative residue of each sieve, which is the particle size content of each level. ：com
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