Concrete Expansion Agent Expansion Principle What is the function of concrete expansion agent

Concrete expansion agent.

It is an ideal material to compensate for shrinkage, and dry shrinkage and temperature difference shrinkage are the main causes. Added to the concrete, after mixing water to generate a large number of expansive crystalline hydrates, so that it produces moderate expansion, under the constraint of steel bar and orthoximity, the resulting expansion energy is converted into compressive stress, this stress can offset the shrinkage tensile stress of concrete in hardening, thus reducing cracks. Waterproof performance: The waterproofing of concrete is mainly to improve its own compactness and water enhancement to meet its impermeability and impermeability.

However, due to the shrinkage of concrete, the stress caused by shrinkage is enough to deform the structure and even cracks. Due to cracking, concrete waterproofing loses one of the most fundamental lines of defense. This is the main cause of leakage in buildings.

Ordinary cement concrete has two major characteristics.

One is shrinkage (dry shrinkage and cold shrinkage with temperature difference) during hydration; The second is low tensile strength and low ultimate elongation.

When the shrinkage value exceeds the limit extension of the concrete, the concrete will crack, causing leakage. It can be seen that "cracking" is an important reason for "seepage", and the concrete with good construction will not seep if it is not cracked, and the premise of seepage prevention is anti-cracking.

HC concrete anti-crack expansion agent is added to the ordinary cement concrete, and a large amount of expanded crystalline hydrate hydrate hydrated calcium sulfoaluminate, that is, aluminite, is produced after mixing water, so that the concrete produces moderate expansion, and the precompressive stress established in the structure of the expanded concrete under the constraints of steel bars and orthoximal position, this compressive stress can offset the shrinkage tensile pressure generated by the concrete in the hardening process, or make it less than the tensile limit of the concrete, so as to prevent the shrinkage and cracking of the concrete. It can be seen that the addition of HC anti-crack expansion agent, due to the expansion compensation contraction, changes the stress and strain state in the concrete hardening process, fundamentally serves the material defects of concrete, so as to solve the problem of cracking and seepage of concrete materials.

Anti-crack expansion agent anti-seepage application for concrete:

1. Realize the self-waterproofing of concrete structure; 2. The super-long cast-in-situ structure is poured after the cancellation of the belt; 3. Crack control of temperature difference of large-volume concrete.

The principle is actually very simple, because when judging it, it can be synthesized by adding it directly.

If he wanted to bulge, he might make her so much more splash maybe a little more full.

The principle of non-bulking agent expansion is some of its basic principles, you go and take a look.

The principle of concrete expansion is mainly derived from thermal expansion and cold contraction.

The function of concrete expansion agent is to compensate for shrinkage, and dry shrinkage and temperature difference shrinkage are the main causes. Compensating shrinkage concrete has the effect of compensating for concrete dry shrinkage and compacting concrete, improving concrete impermeability, and is mainly used in civil engineering in waterproof and anti-cracking two aspects, and now the occasion used more is to prepare high-grade waterproof concrete and appropriately extend the expansion joint or post-pouring belt spacing.

Concrete expansion agent is a kind of high-performance concrete expansion agent with low alkali and low content, which also belongs to calcium sulfur aluminate concrete expansion agent, and the development of its expansion performance is more compatible with the cement hydration system after the transfer. Adding cement dosage of 8 10% expansion agent to concrete can compensate for the shrinkage of concrete, improve the crack and anti-seepage ability of concrete, and make it an impermeable and waterproof concrete with excellent performance.

Concrete expansion agents are divided into three categories, and the concrete expansion agent of calcium sulfuraluminate refers to the concrete expansion agent that is mixed with cement and water and reacted by hydration to form aluminite. Calcium sulfoaluminate-calcium oxide concrete expansion agent refers to the concrete expansion agent that is mixed with cement and water and reacts with hydration to form calcium alum and calcium hydroxide, and calcium oxide concrete expansion agent.

The dosage of expansion agent is selected scientifically and reasonably, and the expansion agent must be adapted in the corresponding concrete mixing plant. The cement is mixed with 8%-12% expansion agent, which can be mixed into compensating shrinkage concrete, which greatly improves the crack resistance and waterproof ability of the concrete structure.

Expansion agent is a chemical admixture, added to cement, when the cement is set and hardened, the volume expands, which plays the role of compensating for the prestress of shrinkage and tension steel bars and fully filling the cement gap. So what is the scope of application of concrete expansion agent? Pi Feng.

First, the main performance:

1. Low dosage: 6 8, its expansion rate is greater than that of UEA (commercial) dosage 12;

2. Low content of sulfine: the content of (K2O Na2O) is much lower than that of U-type expansion agent, which is of great significance;

3. Due to the reduction of the dosage, it does not affect the early strength and later strength, and truly replaces the same amount of cement;

4. It does not increase the loss of concrete slump and has good construction performance.

Application characteristics:

1. Realize the self-waterproofing of the structure: cancel the external waterproof measures and improve the economic benefits 2 3;

2. Cancel the post-pouring belt of the super-long cast-in-situ structure: there is no post-pouring belt for the 60m length of the underground project, and if it exceeds 60m, the post-pouring belt will be replaced by the ZY expansion reinforcement belt, so as to reduce costs and shorten the construction period;

3. Temperature difference crack control of large-volume concrete: ZY products are used to relax the temperature control index, and traditional construction methods such as cooling aggregates and burying cooling pipes in concrete are generally not necessary to save construction costs;

4. Cast-in-place construction of roof: the cast-in-place roof of ZY products is adopted, which has the characteristics of simple structure, low cost, good waterproof durability, etc., and has been widely used. 3. Uses:

1. Underground buildings: such as subways, underground parking lots, underground warehouses, tunnels, mines, civil air defense projects, foundation pits, etc.;

2. Pools, swimming pools, water towers, storage tanks, large containers, granaries, oil tanks, warehouses in caves, etc.;

3. High-strength highway jujube pavement, bridge concrete surface layer, culvert, etc.;

4. Anchor joints of prefabricated components, frame structure joints, pipe joints, grouting materials of post-tensioned prefabricated components, backfilling of post-pouring joints, and magma grouting materials;

5. Cement products: self-stressed, prestressed and steel sleeve prestressed concrete water pipes, floor slabs, columns, beams and columns, waterproof roof panels, etc.;

6. Non-shrinkage pouring between the anchor screws, machine base and concrete foundation of mechanical equipment;

7. Lining protective mortar of cast iron pipe and steel pipe;

8. Self-waterproof rigid roof, mortar impermeable layer, mortar moisture-proof layer, etc.;

9. Construct high-strength, high-impermeability shafts and dam return grooves filled with concrete.

4. Precautions for use:

1. When adding this agent, it can be added at the same time as cement, and then mixed well, add water and stir. Stirring should be extended for 30 to 60 seconds.

2. When pouring concrete, it should be vibrated and compacted, without leakage of earthquake, but not earthquake.

3. This product should be kept moisture-proof. In case of damp agglomeration, it should be crushed and then used.

Not a thing.

The purpose of adding waterproof powder is to form a waterproof mortar when the cement is mixed with mortar, which can be used to plug the leakage and waterproof, and the concrete expansion agent is usually a chemical agent that bridges the cracks generated by the concrete at the beginning and end of the setting or in the curing process, and eliminates the cracks through expansion, so as to achieve the effect of concrete compaction, so it is not the same thing.

Concrete expansion agent is a calcium sulfoaluminate type concrete expansion agent, which does not contain sodium salt, and should not cause concrete alkali aggregate reaction. The durability is good, the expansion performance is stable, and the strength continues to rise. Ordinary concrete often leaks due to shrinkage and cracking, which reduces its use function and durability.

The expansion agent mixed in the cement can be mixed into compensating shrinkage judgment Zen concrete, which greatly improves the crack resistance and waterproof ability of the concrete structure. The external waterproof operation can be canceled, and the pouring joint spacing after dust excavation can be extended to prevent the appearance of temperature difference cracks between large volume concrete and high-strength concrete.

No! The main component of cement swelling agent is iron powder (mixed with aluminum powder), which contains sodium chloride, sodium thiosulfate and other sodium salts. The main principle is that the metal undergoes a chemical reaction, and the reaction produces hydrogen gas to expand, in which aluminum powder and sodium salt are to speed up the reaction.

The main components of concrete expansion agent are calcium sulfoaluminate, calcium aluminate, etc., and the principle of expansion is to generate expansive crystal hydrate.

Concrete expansion agents are strictly forbidden to contain sodium salts. So not only are the two not the same thing, but they cannot be used interchangeably!

Summary. Kiss and kiss; Under normal circumstances, the concrete will be expanded with an expanding agent.

Kiss and kiss; Under normal circumstances, the concrete will be expanded with an expanding agent.

Generally, the concrete is mixed with an appropriate amount of UEA expansion agent (8% 12%), or HE waterproofing agent (4% 10%).

You want to build the ground, without telling the bulking agent! Does stirring add leavening agent?

If you mix the concrete yourself at home, if you don't tell the construction team, the construction team won't add it to you.

Because he has to at least meet your own requirements.

I asked for concrete directly from the batching plant! I didn't mix it myself.

Concrete for the batching plant. In general, it has already been added to you.

Because the mixing plant is generally mixed in proportion.

Have you already added a pennant booster?

In general, if you don't ask for it, you won't. But according to the norm, it is all fake.

What do I want concrete that won't shrink after it solidifies?

No, dear, they have already given you this situation according to the qualified proportion, and you will not imagine how big the contraction is, but the contraction is definitely a miracle.

Will there be a slight shrinkage with the addition of pentagms? Is that right?

Yes, dear, there will also be shrinkage with the addition of expansion agent, but the proportion of shrinkage can be slightly smaller.

But according to common sense, this contraction must still exist, otherwise there will be problems after thermal expansion and cold contraction, and it will bulge.