Latest national standards and inspection standards for building materials (212 edition)

1. Sand:

1. Implementation standards: JGJ52-26, GB/T14684-21

2. Inspection batch: It shall be accepted in batches according to the same origin and specifications stacked on the construction site.

for those who enter the site with a small number at a time and use it as they go in, when the quality is relatively stable, 4 cubic meters or 6 tons can be used as an inspection lot for one month, and those who are insufficient can also be sampled as a batch. 4kg was sampled from 8 different parts at a time.

2. Pebble (crushed stone):

1. Implementation standards: JGJ53-26, GB/T14685-21

2. Inspection batch: It shall be accepted in batches with the same origin and specifications stacked on the construction site, with 4 cubic meters or 6 tons as one acceptance batch, and those less than the above quantity shall be counted as one batch. For those who enter the site with a small number at a time and use it as they enter, when the quality is relatively stable, 4 cubic meters or 6 tons can be used as an inspection lot for a period of one month, and the shortage can also be sampled as a batch. 6kg was sampled from 16 different parts at a time.

III. Concrete test blocks:

1. Implementation standards: GB/T517-21 and GB/T581-22

2. Inspection batches:

(1) Concrete samples shall be randomly sampled at the silicon pouring site

a, and 1m3 plates shall be mixed each time, but not more than.

c, when a continuous casting of concrete with the same mix ratio exceeds 1m3, sampling should not be less than once every 2m3.

(2) For cast-in-place concrete:

a, the concrete with the same mix ratio is sampled at least once per shift

b, the concrete with the same mix ratio is sampled at least once in each acceptance project of the same unit project, with 3 pieces in each group

IV. Mortar test blocks:

1. Implementation standard: JJ/T7-29 < The mortar mixed by each mixer shall be sampled at least once; Every working class shall be sampled at least once; When the mortar strength grade or mixture ratio changes, another test block should be made. At least one set of standard maintenance test blocks shall be retained for each sampling, and the same condition maintenance test blocks shall be determined by the construction situation.

V. Cement:

1. Implementation standard: GB175-27

2. Inspection batch: The factory number of cement is 1, tons to 3, tons according to the annual production capacity of the cement plant, and no more than 4 tons is regarded as an inspection batch. The cement factory number is less than 1, tons and no more than 2 tons according to the annual production capacity of the cement plant.

an inspection lot is less than 2 tons, and an acceptance lot is less than 4T tons for continuous entry. The sampling should be representative, and the total amount of samples with the same amount can be taken continuously or from more than 2 different parts at least 12kg

3. Sampling requirements: According to the standard GB524-22,

① If the cement quality is in doubt or the cement leaves the factory for more than 3 months (quick-hardening portland cement for more than 1 month), it should be re-examined.

② The cement bags of the same manufacturer, the same grade, the same variety, the same batch number and the continuous entry are a batch with no more than 2t, and the bulk cement bags are a batch with no more than 5t, and each batch is sampled at least once.

Extended information:

Classification of building materials:

1. Coarse aggregate The coarse aggregate should be clean macadam with reasonable gradation, good grain shape, uniform and firm texture and small linear expansion coefficient, or crushed pebbles or pebbles, and sandstone macadam is not suitable.

2. Fine aggregate Fine aggregate should be clean natural medium-coarse river sand with reasonable grading, uniform and firm texture, low water absorption and small porosity, or artificial sand produced by special units, and mountain sand and sea sand should not be used.

3. Cement is a powdery hydraulic inorganic cementing material. After adding water and stirring, it hardens in air or water, and firmly bonds sand, stone and other materials together. After hardening, the concrete made of crushed stone cemented with it not only has high strength, but also can resist the erosion of fresh water or salt water.

4. Fly ash is fine ash collected from flue gas after coal combustion, and fly ash is the main solid waste discharged from coal-fired power plants. It can reduce environmental pollution and waste utilization to use fly ash partially instead of cement in construction projects.

5. Admixtures are mainly high-efficiency alkaline agents, which are used to improve the performance of concrete.

6. The product of crushing ore by mineral powder is used to improve the performance of concrete.

Reference: Baidu Encyclopedia: Building Materials.