What materials need to be added to the concrete to achieve crack resistance and impermeability at th

P8 itself is impermeable concrete with an impermeability grade of P8, and it does not have special requirements for structural crack resistance, and the current specification does not stipulate that impermeable concrete must be added with anti-cracking agent, and impermeable concrete only requires a minimum amount of cement.

If you want to consider anti-cracking, shrinkage, etc., consider whether to add anti-cracking agents while considering the construction conditions.

If so, it is advisable to use one with bleed-in effect.

Including: calcium lignosulfonate, sodium lignosulfonate, magnesium lignosulfonate, lignosulfonate superplasticizer is a common ordinary superplasticizer, belongs to anionic surfactant, can be used directly, can also be used as one of the raw materials of composite admixture, because of the cheap, the use is more extensive. Used in mortar, it can improve workability, fluidity, and strength, and the water reduction rate is 8% to 10%.

When the concrete is subjected to the osmotic pressure of water and leakage is not allowed or to be controlled. To use impermeable concrete.

Such as: 1 concrete water tank, the pool wall and the bottom of the pool, bear the osmotic pressure of the water in the box, and do not allow or control the leakage.

2 basements, exterior walls, roofs, floors. Withstand the osmotic pressure of groundwater outside the macro area, and do not allow or control leakage.

3. Pools, water tanks, bathtubs, etc., bear the osmotic pressure of the water in the pool, and do not allow or control leakage.

4 Retaining components, entities, such as dams, withstand the osmotic pressure of water. And it is necessary to control leakage.

5. There is a floor of a room with water, and it bears the osmotic pressure of water (generally not used, but now that the conditions are better, it has also begun to be used.) ）。

6. The roof bears the osmotic pressure of rainwater, and does not allow the rotation or to control the leakage.

It is mainly selected according to the requirements of the waterproof level of the building. As an underground waterproof structure, the concrete structure is generally impermeable concrete.

Impermeable concrete is generally used for reinforced concrete structures used as liquid containers.

The construction unit generally carries out construction in accordance with the design requirements, and the design and use may be recommended if the design requirements are not required.

Impermeability is nothing more than to isolate the flow and penetration of liquid inside and outside the component or called capillary liquid, and the following situations usually require the use of impermeable concrete: structures with high groundwater levels, structures with liquid storage, structures with corrosive or polluting media inside and outside the components, or buildings that are more sensitive to pollutants, etc.!

A little more is used in water conservancy, and then there are parts such as pools with impermeability requirements, which will be indicated in the general design drawings.

It is divided into two categories: reactive admixture and inactive admixture

1. Active admixture. Refers to glassy minerals containing a certain amount of calcium oxide, alumina and silicon oxide, such as fly ash, granulated blast furnace slag, and pozzolana materials. These minerals can react with calcium hydroxide or calcium sulfate precipitated during the hydration of slaked lime or cement at room temperature to form stable compounds with gelling properties.

2. Inactive admixture. Refers to the absence or very little of the viralized minerals, such as finely ground limestone powder and sandstone powder. It plays a filling role in concrete to improve the workability of concrete.

The most widely used concrete admixture in engineering is fly ash, and granulated blast furnace slag, silica fume and zeolite powder are also effectively used for their non-trapped and columbic properties.

If so, it is advisable to use one with bleed-in effect.

Including: calcium lignosulfonate, sodium lignosulfonate, magnesium lignosulfonate, lignosulfonate superplasticizer is a common ordinary superplasticizer, belongs to anionic surfactant, can be used directly, can also be used as one of the raw materials of composite admixture, because of the cheap, the use is more extensive. Used in mortar, it can improve workability, fluidity, and strength, and the water reduction rate is 8% to 10%.

Generally, impermeable concrete has higher requirements for the compactness of concrete, and the main use is superplasticizer, which reduces the free water in the concrete and improves the compactness of the concrete under the premise of ensuring the working performance of the concrete.

Concrete admixture: a substance added to improve and regulate the properties of concrete.

General waterproof pumping agent will do!

Impermeable concrete raw material requirements:

1. Cement: 1) Ordinary Portland cement, the strength is not less than;

2) Use low hydration heat cement, the 7-day hydration heat index of cement is not higher than 275kj kg, and early strength cement with the word r shall not be used;

3) The alkali content of cement must meet the total alkali content of cement in each cubic meter of concrete, which is not greater than.

2. Fly ash: the grade of fly ash is not lower than grade II, and high-calcium fly ash shall not be used.

3. Coarse aggregate: It is advisable to use 5 graded uniform machine crushed stone, and the mud content shall not be greater than 1%.

4. Fine aggregate: In order to reduce the later shrinkage of concrete, it is advisable to use medium coarse sand and fineness modulus. The mud content of sand shall not be greater than 3%.

5. Admixtures:

1) The admixture should be an admixture with low alkali and low heat of hydration. The content is not more than 5% of the cement mass.

2) It has early strength performance.

3) Adopt high-efficiency superplasticizer.

It cannot be generalized, impermeable concrete must be specially designed or constructed for impermeability, not mixed with any materials to solve the impermeability problem.

Generally speaking, impermeable concrete is capable of having a dense internal structure, reasonable aggregate collocation, and minimizing the existence of voids and pores, so that the concrete strength must be very high. What's adulterated? Mixed with fly ash and mineral powder, filled with internal fine pores, and mixed with some expansion agent, so that those aggregates, cement hydration products such as calcium carbonate are squeezed more tightly with each other, and the water cannot pass through!

In most cases, it is doped with expansion agent.