What are the impermeability test steps of concrete test blocks, in layman s terms

When testing the permeability of concrete test blocks by chloride ion permeation method, the concrete test blocks need to be immersed in a chloride ion pool of a certain concentration.

Chloride ions penetrate from one side of the concrete test block to the other side, after a period of test, the concrete test block is taken out, and it is dried, and cut into thin slices along the direction of the chloride ion solution side to the other side, and samples are taken on each sheet, and the chloride ion content is analyzed, so as to determine the concentration gradient in the direction of chloride ion permeation, and calculate the permeability coefficient of the concrete test block according to this.

This method can accurately measure the impermeability of concrete, but the test method takes a long time, at least ten days to several months. For concrete test blocks with weak permeability, it takes a relatively longer time.

The figure is as follows: (This is an overall graph).

1. Test block production and maintenance: make cylindrical or round table shape according to the model of the impermeability instrument, 6 pieces per group, dismantle the mold for 24 hours, brush off the cement slurry film at both ends with a wire brush, and raise it for 28 days;

2. Take out the test block and dry the surface one day before the test (if it is not dried, the sealing material will not stick);

3. Coat a layer of sealing material on the side of the test block (generally paraffin, some use asphalt, but it is too dirty);

4. Press the test block into the mold that has been preheated (30 40) by the oven (preferably with a press), release the pressure after cooling, and install it on the impermeability meter for testing;

5. The water pressure of the test starts from the beginning, and then increases the water pressure every 8 hours, and the water seepage of the end face of the specimen should be observed at any time;

6. When there is water seepage in 3 of the 6 specimens, the test can be stopped and the water pressure at that time can be recorded.

7. The impermeability of concrete is calculated by the maximum water pressure when 4 of the 6 specimens in each group do not have water seepage, and the calculation formula is:

s=10h－1

Where: s - concrete impermeability mark, h - water pressure (mpa) when water seepage occurs in 3 of the 6 test blocks.

1.Concrete is made into a standard test block, and there are three sizes of compressive test blocks, namely 10cm 10cm 10cm, 15cm 15cm 15cm, 20cm 20cm 20cm, of which the standard size is 15cm, and the function is to bear pressure to calculate the compressive strength of concrete, which is the concrete strength represented by itself.

2.The impermeability size of concrete, the diameter of the upper mouth is 175mm, the diameter of the lower mouth is 185mm, and the height is 150mm.

Impermeable concrete improves the pore structure by increasing the compactness of concrete, thereby reducing the permeability channel and improving the impermeability.

Compressive strength refers to the pressure that can be withstood per unit area under the action of external forces, and also refers to the ability to resist pressure damage. Compressive strength is generally divided into cubic compressive strength and prismatic (axial) compressive strength in construction engineering.

For high-strength rocks, the sample size is 5 5 5 for cube-shaped rocks, 7 7 7 for medium-strength rocks, and 10 10 10 for soft rocks. For rocks with uneven mineral composition, the sample size of the cube shape should be larger than that of rocks with uniform mineral composition.

There are three sizes of compressive test blocks, namely 10cm 10cm 10cm, 15cm 15cm 15cm, 20cm 20cm 20cm, of which the standard size is 15cm, the function is to bear pressure to calculate the compressive strength of concrete, that is, the concrete strength itself represents.

There are two specifications of impermeability test block, 1. Cylindrical test mold with an upper diameter of 175mm, a lower mouth diameter of 185mm, a high diameter of 150mm, and a height of 150mm. The first specification is commonly used now. The permeability of the concrete is determined by how many hours after the test machine uses water pressure to observe whether there are water traces on the opposite side.

I feel that the decoration is very practical, and we and the size should be in good condition.

The compressive strength of concrete is made of a cube with a side length of 150mm, and it is cured to 28 days old under standard conditions (temperature 20 2, relative humidity above 95%).

The performance of impermeable concrete is tested by using a cylindrical body with a top diameter of 175mm, a bottom diameter of 185mm and a height of 150mm, and a group of impermeable test blocks (a group of 6 pieces) should be retained every 500m3 of continuous pouring concrete, and each project shall not be less than 2 groups.

150mm, 150mm 300mm prism is used as the standard specimen for the determination of the axial compressive strength of concrete.

6 pieces. The same concrete strength grade, impermeability grade, the same mix ratio, the production process is basically the same, each unit of the project shall not be less than two groups of impermeability test blocks (each group of 6 test blocks), continuous pouring concrete every 500 should be left with a group of impermeability specimens (a group of 6 impermeability specimens), and each project shall not be less than 2 groups; The number of impermeability test blocks with ready-mixed concrete should be determined according to the scale and requirements of the structure, and the compressive strength specimens should be indwelled at the same time as the impermeable test blocks and should be taken from the same tray of concrete mixture. Sampling method in item (2) of ordinary concrete, according to the specification to send 3 groups.

Precautions for concrete impermeability test blocks.

Impermeable concrete can improve the compactness, hydrophobicity and impermeability of concrete by adjusting the mix ratio of concrete, mixing admixtures or using new varieties of cement, etc., and improve the pore structure, so as to reduce the permeability channel and improve the impermeability, so that it can meet the requirements of impermeability pressure.

The commonly used method is to mix with air-entraining admixtures to produce inconnected bubbles inside the concrete, cut off the capillary channel, and change the pore structure, so as to improve the impermeability of the concrete. In addition, reducing the water-cement ratio, selecting appropriate varieties and strength grades of cement, ensuring the quality of construction, especially paying attention to vibration and compaction, sufficient maintenance, etc., all play an important role in improving impermeability.

The above content refers to Encyclopedia - Concrete impermeability test block.

In general, when the design has impermeability requirements for concrete or the pouring site has impermeability requirements for concrete, according to the impermeability grade of concrete.

Concrete samples should be retained and impermeability tests should be performed.

In the use of chloride ions.

Permeability method to test concrete test blocks.

The concrete test block needs to be soaked in a pool of chloride ion water of a certain concentration.

Chloride ions penetrate from one side of the concrete test block to the other side, after a period of test, the concrete test block is taken out, and it is dried, and cut into thin slices along the direction of the chloride ion solution side to the other side, and samples are taken on each sheet, and the chloride ion content is analyzed, so as to determine the concentration gradient in the direction of chloride ion permeation, and calculate the permeability coefficient of the concrete test block according to this.

Impermeable concrete does not do impermeable concrete test blocks, what experiments can be remedied.

If there is no impermeable silver car touching the concrete test block, it can be remedied by other methods, such as: 1Concrete is inspected using non-destructive testing techniques (such as ultrasonic, electromagnetic waves, etc.) to evaluate its impermeability.

2.A hydrostatic test is carried out, in which a concrete component or sample is placed in water to observe for leakage. 3.

Chemical analysis is carried out, and the sailor analyzes the chemical composition and structural characteristics in the concrete to evaluate its impermeability. 4.Refer to the existing relevant materials and standards to evaluate and analyze the mix ratio, material selection, construction technology, etc. of concrete.

It should be noted that when performing any of the above methods, professional operation and judgment are required. At the same time, it is also recommended to strengthen the production and testing of anti-permeability concrete test blocks in the projects that have not been discussed.