I want to know clearly the role of the indwelling of the concrete test block.

The retention of concrete test blocks is divided into homotrophic test blocks and standard test blocks: the number of retention groups of standard test blocks should be retained according to the construction amount of concrete, satisfying every 100 square meters and not exceeding 100 plates of retention group; The homotrophic test block is indwelling for each structural part, and the number of indwelling groups should not be less than five groups and not less than three groups. After demoulding, the standard culture test block must be maintained in the standard maintenance room, and the same culture test block is sprinkled and cured in the construction (the same way as the structure maintenance).

The reason for the indwelling homotrophic test block is to know the true strength of the concrete, the curing days should be tested before the concrete construction, the strength of the same number of days is the same as the strength of the standard culture, as the number of days of homotrophic curing, if the test is not done, it has to meet the concrete homotrophic accumulation of the standard 28d 600, and at the same time does not exceed 60d; The total amount of concrete for 56d is 1200, and it does not exceed 120d.

If the mold is removed, it is divided into load-bearing template and non-load-bearing template, and the load-bearing template can be divided into several categories according to the structural type and structural span.

Standard maintenance: check the mix ratio to prove that the concrete you pour each time is in strict accordance with the requirements of the mix ratio to build.

Same conditions: Check what is the specific strength value of the concrete poured according to the mix ratio when you actually pour and cure, and whether it meets the design requirements.

Mould removal: whether the actual strength of the concrete actually poured on site can reach the formwork removal standard.

Impermeability: Whether the concrete constructed according to the mix ratio reaches the design impermeability level.

Civil engineering: commercial concrete is a group of every 100 square meters, standard maintenance, and self-mixing is a group of every 100 pokes. There are a lot of tricks to do it. It is recommended to discuss in detail with the person in charge, because there are normative requirements for the later assessment.

The function of the indwelling test block: send it to the laboratory for experiments, and then the laboratory will issue a report, and the laboratory report is part of the data.

According to the concrete construction quality acceptance specification for the same conditions of natural curing specimens of the equivalent curing age and the corresponding strength of the specimen representative value, it is advisable to determine according to the local temperature and maintenance conditions according to the following provisions:

1.The equivalent maintenance period can be taken according to the age corresponding to the daily average temperature reaching 600 ·d day by day, and the age of 0 and below is not counted. The equivalent curing age should not be less than 14 days and should not be greater than 60 days;

2.The strength representative value of the curing specimen under the same conditions should be determined according to the strength test results according to the leakage and Weifeng provisions of the current national standard "Concrete Strength Inspection and Evaluation Standard" GBJ 107, and then multiplied by the conversion factor; The conversion factor should be taken as, and it can also be adjusted appropriately according to the local test statistics.

According to the provisions of the "Code for Acceptance of Construction Quality of Concrete Structure Engineering", the construction of concrete structure engineering should be retained in accordance with the provisions of the standard maintenance of concrete strength test blocks.

Concrete strength specimens should be randomly selected at the place where the concrete is poured. Sampling and specimen retention shall comply with the following provisions:

For each 100 trays of concrete with the same mix ratio of no more than 100m3, sampling shall not be less than once;

When less than 100 trays of concrete with the same mix ratio are mixed in each working shift, sampling shall not be less than once;

When a continuous pouring exceeds 1000m3, the concrete of the same mix ratio shall be sampled less than once every 200m3;

For each floor, the same mix ratio of the trillion excitation concrete, sampling shall not be less than one first sock;

At least one group of standard curing specimens should be retained for each sampling, and the number of indwelling groups for curing specimens under the same conditions should be determined according to actual needs.

The physical and mechanical properties and long-term properties of ordinary concrete, and the durability test block, except for the impermeability and fatigue test, are all 3 pieces.

as a group. The test blocks for each group of tests should be taken out of the concrete transported by the same tray or the same truck, and the test blocks should be made immediately.

The same division of the project, the same variety, the same strength grade of 600OC D with the same conditions of curing specimens for an acceptance batch, the strength value of the test block should be multiplied by the conversion coefficient according to the current "concrete strength inspection and evaluation standards" (GBJ107) for inspection and evaluation. According to the number of test block groups, the statistical method and the non-statistical guessing method were used to evaluate the group. The formula should be listed and the calculation process should be written.

If the acceptance criticism is qualified, it will pass the acceptance; If the acceptance criticism is unqualified, the strength of a certain part or all of the concrete in the acceptance batch is presumed through the method of non-damage or micro-damage inspection. Under normal circumstances, a set of 600 oC d maintenance specimens under the same conditions should be left for each strength level of each structural layer of the main structure involving structural safety.

For example, a layer of beams, slabs and frame columns of a frame structure. For the structural column, because it is not a component that affects the structural safety, the test block with the same condition can not be retained. For foundation engineering, the components that affect the structural safety should be determined, and then the test blocks under the same conditions should be retained.

For example, for the concrete strip foundation of the brick-concrete structure, the concrete strip foundation should be left with the same condition test block. The foundation ring beam does not have to be left with the same condition test block.

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Concrete is a material often used in construction projects, and concrete can be divided into three types: compression, impermeability, and bending. Concrete test blocks are usually carried out before the start of the project, so how many sets of concrete test blocks are left in place? What should be paid attention to in concrete test blocks?

Concrete test blocks are left in several groups.

According to the relevant regulations, if 100 cubic meters are poured continuously, at least a group of standard test blocks need to be retained, and less than 100 cubic meters should be retained a group of standard test blocks. If more than 1,000 cubic meters are poured continuously, at least one group of standard test blocks should be left for every 200 cubic meters.

What should be paid attention to in concrete test blocks.

1. It is necessary to designate the specific position of the staff, and the personnel of the test can not be changed frequently, and some skilled, responsible, and competent personnel should be selected to take up the post. When carrying out the inventory, disassembly and assembly of the test block mold, we must be careful, and we must also pay attention to check the degree and size of the mold. Note that the separator must be evenly painted, and the standard mold test should be used when testing the mold.

2. Before the production of concrete pure soil, the staff needs to carefully check the ratio of raw materials, check whether the test blocks are consistent, and supervise the relevant personnel to input data. After the concrete pure soil leaves the factory and enters the construction site, it needs to be tested for slump. In addition, before the concrete test block is made, it is necessary to select the concrete pure soil clinker together with the supervision and construction visa.

3. The clinker needs to be poured into the mold twice and pounded from the outside to the inside, and the clinker is added while pounding. When mixing, pay attention to the air in the test block, and the surface of the test block should be full of slurry, so as to prevent the concrete pure soil from sinking due to plastic deformation. In addition, after the test block is formed, it should be placed in situ or in the open air, and it needs to be covered tightly with black plastic, which can prevent the water from evaporating too quickly.

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Requirements for the retention of concrete cast-in-place pile test blocks: 1. A set of standard curing. 2. A group of maintenance under the same conditions.

3. If it is winter construction, leave a group of test blocks for normal temperature maintenance. 4. Each construction team must retain a group of test blocks of up to 100 cubic meters. For piles with a diameter of more than 1m or piles with a single pile of concrete exceeding 25m3, 1 set of specimens should be set for each pile body concrete; For piles with a diameter of no more than 1m or piles with a single pile of concrete not exceeding 25m3, 1 group of specimens shall be left for each pouring shift, and 3 specimens shall be left for each group of specimens.

Extended information: Controlling the quality of the original material for concrete dismantling. The cement entering the site should be verified with the factory certificate, and the stability and strength of the cement should be checked, such as the cement that has been stored for more than 3 months or is agglomerated by moisture, and must be applied according to the retest number after the retest.

Choose clean medium coarse sand, and choose stones with good grading and mud content of no more than 2%. The mixing ratio of mixed concrete should be based on the required strength grade, the slump of construction, and the raw materials of the royal grasp by the laboratory from multiple groups of test ratios. Correct measurement, the material weight deviation of each tray of concrete should not exceed the following provisions:

cement, external mixture; 2%；Coarse and fine aggregates: 3%; Water and admixture solution: 2%.

Balance Pulse Fluid article

Ordinary concrete sampling standards for the same part, the same number, the same rebirth distribution production process, continuous pouring of concrete every 100 square retaining not less than a group of 7 days and a group of 28 days test block, less than 100 square meters according to 100 square indwelling test block. Concrete, for short"Concrete (tóng).": refers to the general term of engineering composite materials that cement aggregates into a whole by cementitious materials.

Dust type refers to the commonly spoken concrete, the word refers to the use of cement as cementitious materials, sand and stone as aggregates; Cement concrete, also known as ordinary concrete, is widely used in civil engineering engineering when it is mixed with water (which can contain admixtures and admixtures) in a certain proportion and is mixed to obtain cement concrete. Historical archaeologists have found that the ancestors of Lingjiatan 5,000 years ago were not only able to make exquisite jade tools, but also began rice farming, raising or hunting pigs, deer, birds and poultry and other animals to enrich the diet and varieties. In addition, in the construction of houses, they have learned similar to the steel and concrete spikes

digging grooves to fill the soil, wooden bones to support the mud wall". 5,000 years ago, the Lingjiatan people did not simply build houses, it has been proved that the Lingjiatan people at that time had already understood the construction process of "digging grooves and filling the soil, and supporting the mud walls with empty bones of wooden guessing stoves", which is very similar to today's reinforced concrete. Staff member.

Article 1 of GB50204-2002 "Code for Acceptance of Construction Quality of Concrete Structure Engineering" (2011 Edition) stipulates as follows: the strength of structural concrete and other combustion-only collapse levels must meet the design requirements. Specimens used to check the concrete strength of structural components should be randomly selected at the place where the concrete is poured.

Sampling and specimen retention shall comply with the following provisions: 1. For every 100 trays of concrete mixed and not exceeding 100m3 of the same mix ratio, sampling shall not be less than one state; 2. When there are less than 100 trays of concrete with the same mix ratio mixed in each working shift, the sampling shall not be less than once; 3. When a continuous pouring exceeds 1000m3, the concrete of the same mix ratio shall be sampled less than once every 200m3; 4. For each floor of the concrete, the same mix ratio of concrete, sampling shall not be less than once; 5. At least one set of standard maintenance specimens should be retained for each sampling, and the number of indwelling groups of curing specimens under the same conditions should be determined according to actual needs. Test Method:

Check the construction records and specimen strength test reports.

The requirements of the specification for the retention of concrete pouring test blocks are as follows:

1. The concrete test block should be randomly sampled at the pouring site of the concrete trembling reed soil. For every 100 trays of concrete mixed and not exceeding 100 cubic meters of concrete with the same mix ratio, sampling shall not be less than once.

2. When the concrete of the same mix ratio is less than 100 trays mixed in each working shift, the sampling shall not be less than once.

3. When a continuous pouring exceeds 1000 cubic meters, the sampling of concrete with the same mix ratio shall not be less than once every 200 cubic meters.

4. For each floor and the concrete with the same mix ratio, sampling shall not be less than once.

5. Each sampling should be at least one set of standard curing test blocks (one group is 3 cube test blocks).

Introduction to Concrete Pouring:

Concrete pouring refers to the process of pouring concrete into the mold until plasticization, in civil engineering and construction projects, concrete and other materials into the mold to make a predetermined shape, concrete pouring, the free height of concrete should not exceed 2m, when more than 3m should take corresponding measures.

Before pouring, the garbage, soil, oil stains and other debris on the steel bar in the formwork should be removed, and the cement and mortar cushion blocks and plastic cushions of the steel bars should be checked to see if they are well mated. If wooden formwork is used, it should be watered to make the formwork moist. The sweeping port of the column formwork should be closed after removing debris and stagnant water.

When pumping concrete, it is necessary to ensure that the concrete pump works continuously, if there is a failure, the stop time is more than 45 minutes or the concrete is segregated, the remaining concrete in the pipe should be washed immediately with pressurized water or other methods.