• Published 2023/04/09
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  • Category Blog 1

The UHPC concrete and the admixtures used in it – The use and properties

Have you ever thought that you can use significantly high-strength concrete? What properties should such material have to be categorized as high-strength? Is it possible to use it anywhere? To answer all these questions it is recommended to be familiar with Ultra High-Performance Concrete. A lot of chemical admixtures in this product led to the aforementioned title for such concrete. Generally, it is said that concrete is a widely used product all over the world.

Suitable retrofitting

Nevertheless, consider that the use of this product in Iran has been 2 times more than in other countries. One of the highly important issues in some structures is the ultimate strength. When you use conventional concrete for a structure, you are not able to flex and implement various models. Therefore, the UHPC concrete was produced so that the engineers implement their scheme in the best form. The price of this product is 4 to 5 times more than conventional concrete; whereas, its efficiency compensates for its expensive price.

What material exists in the UHPC concrete?

The material used to produce this product and develop strength characteristics is not particular material. The Poly Carboxylate Ether is one of the important materials in the product. In addition to this material, a lot of other elements are used along with each other to form the outstanding properties of UHPC concrete.

Each of these elements has special properties. To increase the strength and efficiency of the product, you can use more of each admixture depending on their properties. Although each admixture has particular properties, they complete each other and eventually form the such product.

The strength against environmental or other factors is not the only thing to deserve such a name for this type of concrete; this product deserves Ultra High-Performance Concrete despite its high cohesion properties. The structure of this product is designed in a way that everything is placed in a small form beside each other.  

Silica fume which is the by-product of the process of Silicon metal or Ferrosilicon alloy production in the electric arc furnace has microscopic particles of 0.05 to 0.25 micrometers. Steel fiber is the element that can make the material more tensile and increase its flexibility in ductility. Other admixtures include fly ash, polymer fibers, air-entraining, glass fibers, rice bran, PDR polymers, superplasticizers, and pozzolans like silica fume and acrylics.

The Poly Carboxylate-based superplasticizers

It is necessary that some materials develop homogenous and consistency properties in the final paste considering that little amount of water is used when making UHPC concrete. The comparison of the amount of water with respect to the amount of cement in the UHPC with conventional concrete showed that the UHPC approximately has 0.2% less water than the conventional concrete. To compensate for this shortage, you need superplasticizers! These elements can increase the homogenous and consistency properties in the UHPC to a great extent. 

But why should the final paste be smooth? If you want to facilitate the concrete casting process and increase the slump, you will need this element. You certainly should not neglect the development of concrete mass strength using strong superplasticizers after curing.

What is the characteristic of steel fibers in the paste?

This type of fiber has an important role in the final paste. Assume you have a concrete paste that has not been formed and does not have a good performance. In fact, this paste is useless. When the steel fiber is added to the UHPC, the final paste becomes ductile.

The amount of this type of fiber to develop such properties varies and depends on the number of other materials. Generally, it is said that this element forms almost 5% of concrete volume. 

The use of fine aggregates (Siliceous aggregates)

The type of aggregates used to make this kind of paste should be fine to a great extent i.e. each aggregate should be a maximum of 2 mm. The quartzite aggregate is used to make this product.

When the size of aggregates reduces, you can see how much the strength of the paste and its stress concentration has been increased and reduced, respectively.

Things you should know about choosing the Ultra High Performance for this paste

The suitable name for this product is UHPC. But what does it mean? What do these words intend to convey? A lot of products are abbreviated so that individuals pronounce them in a better form. 

It is time-consuming to express UHPC as (Ultra High-Performance Concrete), and you may also pronounce some words incorrectly and not convey the main concept to the listener. The aforementioned words mean wonderful concrete with high efficiency.

The Ultra High-Performance Concrete has been given to this paste since it can withstand more than 150 Mpa after drying. In 1997, engineers in America used this paste for the first time to build a bridge. In pursuit of this success, other engineers around the world started using this product. 

The superplasticizer, Silica fume, Poly Carboxylate, and fine aggregates in this product made it superior to conventional concrete. When talking about durability, the product named UHPC shines. It is very attractive that by the construction of a bridge or silo your name remains on that even after a hundred years.

What can be made by this product?

The efficiency and use of such paste are not limited to structures like bridges or oil platforms and the following items are other uses of the paste:

  • Monorail
  • A stadium that needs high strength
  • For pre-stressed girders
  • The design and production of sections with small surface
  • The Poly Carboxylate in the paste makes your work easier to solve for structures that require more time to make.
  • Reconstruction of bridges that require repair
  • Improving the performance of the bridge against vibrations
  • Replacing reinforcement bars that are normally used 
  •  
  • You can count on the perfect performance of this product if you want to develop columns of a building or bridge piers with a bigger span.
  • Construction of different types of bridge

Other properties of the ultra-high-performance concrete

This type of concrete withstands much more pressure than conventional concrete; this pressure is 10 times more than the conventional concrete which is daily used. This characteristic depends on steel fibers. It is better to pay attention to its high durability along with this ability and high strength. A product can have high durability and lifetime if it shows resistance against many factors. 

Purchasing UHPC admixtures from Capco

To finally have a high-quality product, you have to use original high-quality admixtures. Choose Hamgerayan Production Company (Capco) to put your request into practice. You can save 021189331 on your cellphone so that you can directly have access to this Company.

Conclusion

It has been many years that the world has stepped toward development and keeps on going. The products produced today are of high quality. This can be clearly observed in the UHPC. The concrete with this title has been produced from elements, each of which has unique properties.

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