Designing Buildings - User contributions [en]

Ladle shrouds

2025-10-15T10:36:38Z

2025-10-15T10:20:11Z

Junhuamachinery:

You may be looking for good ladle shroud suppliers in China. Here are five companies you should know: Puyang Refractories Group, Wuxi Nanfang Refractories Company, RHI China, Vesuvius China, and Henan Yangyu Refractories Co., Ltd. Each company is known for great product quality. They use advanced technology. They also sell to many places. These companies give solutions that help steelmakers do well.

[[w/index.php?title=Special:Upload&wpDestFile=The-strcture-of-the-ladle-shroud-1024x495.jpg.webp|1024px]] the strcture of the ladle shroud

== Key Takeaways ==

* Learn about the [https://hyrefr.com/how-to-choose-ladle-shroud-from-a-china-factory/ top ladle shroud makers] in China. These are Puyang Refractories Group, Wuxi Nanfang, RHI China, Vesuvius China, and Henan Yangyu. Each company has special products and services.
* Check [https://hyrefr.com/5-key-factors-behind-ladle-shroud-cracking/ product quality] by looking at materials and certificates. Find companies with ISO certificates to make sure they have good standards.
* Think about customer service and help. Pick suppliers who give technical help and care after you buy. This will make your experience better.
* If you live outside China, check if they export. Puyang Refractories Group and Vesuvius China know a lot about shipping worldwide.
* Use a checklist when you pick a supplier. Look at how much they make, product quality, certificates, customer service, and what other steelmakers say.

== Comparison Table ==

=== Key Features ===

It is important to pick the [https://hyrefr.com/how-to-choose-ladle-shroud-from-a-china-factory/ best ladle shroud supplier]. You should know what makes each company special. The table below shows the main facts about the top five manufacturers in China. You can check where they are, how old they are, what they sell, and their certifications.

Company Name Founded Locations (Main) Main Products Certifications

[[File:ladle shroud manufacturer]]

Tip: This table helps you see which company fits your needs. If you want a supplier with places in China and the USA, choose Puyang Refractories Group. If you need certain certifications, RHI China and Vesuvius China have ISO 9001 and ISO 14001.

All these companies make [https://hyrefr.com/new-generation-ladle-slide-gate-system-for-performance-improvement/ ladle shroud products]. Their years in business and certifications can help you choose. Look at their main products to find what works for your project.

== Ladle Shroud Manufacturer Profiles ==

[[w/index.php?title=Special:Upload&wpDestFile=1-1024x786.jpg.webp|1024px]] Figure 1. Schematic diagram of liquid steel casting equipment

=== Puyang Refractories Group ===

If you want a trusted company, learn about Puyang Refractories Group. They started in 1988 in Puyang, China. The company grew from a small plant. In 2008, it became public on the Shenzhen Stock Exchange.

* Puyang Refractories Group is big in China and worldwide.
* They have 13 factories and 23 branches in many countries. These include the USA, India, Korea, Russia, Ukraine, and Serbia.
* They own five mines in China. This helps them keep their product quality high.

Here is a quick look at what they make:

Product Line Description

Purging Plug

This is their top product and is very popular in China.

Seating Block

This is one of many refractories they sell.

Castable

Used for different heating jobs.

Slide Gate Nozzle

Needed for making steel and other metals.

Black Refractories

Used when things get very hot.

MC/AMC

Special refractories for factories.

Functional Refractories

Includes nozzles, ladle bricks, and items for casting.

Silicon Nitride Bonded Silicon Carbide Bricks

Used in making aluminum.

You can trust their products. They have ISO9001:2000 and other important certificates. Puyang Refractories Group is the biggest supplier for Chinese steel companies. They make about 700,000 tons of refractories each year. If you want a company with many products and global reach, choose them.

Note: Puyang Refractories Group has a strong supply chain. Their big factories make them a good choice for large steel projects.

=== Wuxi Nanfang Refractories Company ===

Wuxi Nanfang Refractories Company has been around for a long time. It is part of Wuxi Nanfang Chemical Auxiliary Co., Ltd. The parent company has made chemicals for almost thirty years. Later, Wuxi Nanfang started making high-purity products for many uses. These include screens and new medicines.

Here is what they make and their standards:

Primary Products Quality Standards

Ladle Shroud

National high-tech company

SEN

Company that keeps promises

Rod Stopper

Grade-A Supplier for Baosteel

Slide plate gates

Purging Plugs for Ladle

Purging Plugs for BOF&EAF

Refractory for the body of the Tundish and Ladle

Wuxi Nanfang Refractories Company cares about quality. They are a Grade-A supplier for Baosteel. They are known for being reliable. If you want a company with a strong background and high-tech focus, pick them.

=== RHI China ===

RHI China is a famous name in refractories. The company started in 1999. They quickly became a leader in high-grade products. Their products are used in places with heat over 1,200°C. These places include steel, cement, metals, and glass.

Here is what they offer:

Product Offerings Description

High-grade refractory products

Used in steel, cement, metals, and glass.

Full performance-based solutions

They help from raw materials to finished products.

RHI China cares about the environment. They have a Green Mining Certificate. This means they follow green rules and local laws. In the last five years, RHI China worked with Jinan New Emei Industries Co. Ltd. They now have more products and customers. They also opened a new plant in Laiwu. This plant can make up to 80,000 tons of refractories each year.

Tip: If you want a company with new technology and green ideas, RHI China is a good choice.

=== Vesuvius China ===

Vesuvius China is part of the big Vesuvius Group. This group has a long history in refractories. Their main offices are in Suzhou, Shanghai, and Wuhan. Vesuvius China makes many products for steelmaking. These include ladle shroud, flow control products, and casting refractories.

Their products meet strict world standards like ISO 9001 and ISO 14001. This means their products are safe and high quality. Vesuvius China works with top steelmakers in China and other countries. Their global team brings new ideas to customers.

If you want a company with worldwide reach and new ideas, Vesuvius China is a great choice.

=== Henan Yangyu Refractories Co., Ltd. ===

Henan Yangyu Refractories Co., Ltd. is in Zhengzhou, Henan. The company started in 2006. They quickly became known for good quality and service. They offer [https://hyrefr.com/ko/products/ many refractory products]. These include ladle shroud, nozzles, stoppers, and slide gates.

Here is what they make and their certificates:

Product Categories Quality Certifications

ladle shroud,tundish stopper,SEN

ISO9001

sldie gate plate(LG21,CS60,1QC,LS70,Flocon4200,6300.cs80

ISO9001

ladle nozzle

ISO9001

Henan Yangyu Refractories Co., Ltd. cares about quality and safety. Their products are used in many steel plants and kilns. If you want a company with many products and high standards, consider them.

== Comparison and Selection Tips ==

[[w/index.php?title=Special:Upload&wpDestFile=60b4fd07f65b4d8c88ddc37c77b847aa.webp|File:60b4fd07f65b4d8c88ddc37c77b847aa.webp]] Image Source: [https://unsplash.com/ unsplash]

=== Product Quality ===

You want your steel plant to work well. Product quality is very important. Top Chinese manufacturers use strong materials. These include alumina, magnesia, and graphite. These help ladle shrouds stand up to high heat. They also make them last longer. New designs have anti-erosion linings. This makes them even stronger. Here are some common steps for quality control:

Quality Control Measure Description

Material Selection

Strong refractory materials help with high heat.

Coating Application

Smooth coatings stop sticking and help flow.

Construction Techniques

Careful mixing and setup give better strength.

Temperature Monitoring

Baking is checked often for even quality.

Regular Training

Workers get training to keep up quality and safety.

Check if a supplier uses these steps. This helps you get good ladle shroud products every time.

=== Customer Service ===

Good customer service helps you a lot. Top companies in China give technical support. They answer fast and help with setup. Some companies have teams to help you install and fix problems. Others give tips to make steelmaking better. You can get help from your first order to after-sales care.

Tip: Ask about after-sales help before you buy. Good service means less trouble later.

=== Export Experience ===

If you are outside China, you need a supplier who knows global shipping. Top companies like Puyang Refractories Group and Vesuvius China have lots of export experience. They know how to do paperwork and follow rules. This means your ladle shroud order comes on time and meets your country’s needs.

=== How to Choose ===

Choosing the right supplier can be hard. You can make it easier with a checklist:

* Check the company’s production size.
* Look at product quality and how it works.
* Make sure they have ISO 9001 or other certificates.
* Test their customer service and support.
* Read what other steel makers say.

You want a partner who gives good products and helps you. Take your time, ask questions, and pick the supplier that fits your project best.

You have learned about the top five ladle shroud makers in China. These companies are known for good quality and new ideas. They also help customers when needed. When picking a supplier, think about what you need. Ask questions to make sure they are right for you. Want to know more about ladle shroud features? Look at this easy table:

Feature Description

Material

Premium alumina-graphite or alumina-zirconia graphite

Thermal Shock Resistance

High—no preheating needed

Erosion Resistance

Special slag line design for long service life

Customization

Options for argon sealing and bell designs

Contact these companies if you want prices or more info. You can also look for more resources to find the best choice for your steel plant.

== FAQ ==

=== What is a ladle shroud used for? ===

A ladle shroud protects molten steel from air as it moves from the ladle to the tundish. You get cleaner steel and fewer defects. It also helps control the flow.

=== How do I choose the right ladle shroud supplier? ===

You should look at product quality, certifications, customer service, and export experience. Ask for samples or references. Pick a supplier who understands your needs.

=== Can I get custom ladle shrouds for my steel plant? ===

Yes! Most top suppliers offer custom designs. You can share your requirements. They will help you find the best fit for your process.

=== How long does it take to receive an order from China? ===

Delivery times vary. Usually, you can expect 2–6 weeks, depending on your location and order size. Ask your supplier for a shipping estimate.

Tip: Always confirm lead times before placing your order. This helps you plan your production schedule.

[[Category:Articles_needing_more_work]]

File:Ladle shroud manufacturer.jpg

2025-10-15T10:17:43Z

Junhuamachinery: ladle shroud manufacturer

ladle shroud manufacturer

Ladle shrouds

2025-10-15T10:02:28Z

Junhuamachinery: Created page with "You may be looking for good ladle shroud suppliers in China. Here are five companies you should know: Puyang Refractories Group, Wuxi Nanfang Refractories Company, RHI China, Ves..."

You may be looking for good ladle shroud suppliers in China. Here are five companies you should know: Puyang Refractories Group, Wuxi Nanfang Refractories Company, RHI China, Vesuvius China, and Henan Yangyu Refractories Co., Ltd. Each company is known for great product quality. They use advanced technology. They also sell to many places. These companies give solutions that help steelmakers do well.

[[File:the-strcture-of-the-ladle-shroud-1024x495.jpg.webp|1024px]] the strcture of the ladle shroud

== Key Takeaways ==

* Learn about the [https://hyrefr.com/how-to-choose-ladle-shroud-from-a-china-factory/ top ladle shroud makers] in China. These are Puyang Refractories Group, Wuxi Nanfang, RHI China, Vesuvius China, and Henan Yangyu. Each company has special products and services.
* Check [https://hyrefr.com/5-key-factors-behind-ladle-shroud-cracking/ product quality] by looking at materials and certificates. Find companies with ISO certificates to make sure they have good standards.
* Think about customer service and help. Pick suppliers who give technical help and care after you buy. This will make your experience better.
* If you live outside China, check if they export. Puyang Refractories Group and Vesuvius China know a lot about shipping worldwide.
* Use a checklist when you pick a supplier. Look at how much they make, product quality, certificates, customer service, and what other steelmakers say.

== Comparison Table ==

=== Key Features ===

It is important to pick the [https://hyrefr.com/how-to-choose-ladle-shroud-from-a-china-factory/ best ladle shroud supplier]. You should know what makes each company special. The table below shows the main facts about the top five manufacturers in China. You can check where they are, how old they are, what they sell, and their certifications.

Company Name Founded Locations (Main) Main Products Certifications

Puyang Refractories Group Co., Ltd.

1988

Puyang, Henan; Shanghai; Beijing; Liaoning; Yunnan; Jiangsu; Anhui; Pittsburgh, USA

Shaped/unshaped refractories, functional refractories, application devices

N/A

Wuxi Nanfang Refractories Company

1994

Wuxi, Jiangsu

Ladle shroud, tundish nozzle, slide gate plates

ISO 9001

RHI China

1999

Shanghai, Beijing, Dalian

Ladle shroud, continuous casting refractories

ISO 9001, ISO 14001

Vesuvius China

2001

Suzhou, Jiangsu; Shanghai; Wuhan

Ladle shroud, flow control products, casting refractories

ISO 9001, ISO 14001

Henan Yangyu Refractories Co., Ltd.

2006

Zhengzhou, Henan

Ladle shroud, nozzle, stopper, slide gate

ISO 9001

Tip: This table helps you see which company fits your needs. If you want a supplier with places in China and the USA, choose Puyang Refractories Group. If you need certain certifications, RHI China and Vesuvius China have ISO 9001 and ISO 14001.

All these companies make [https://hyrefr.com/new-generation-ladle-slide-gate-system-for-performance-improvement/ ladle shroud products]. Their years in business and certifications can help you choose. Look at their main products to find what works for your project.

== Ladle Shroud Manufacturer Profiles ==

[[File:1-1024x786.jpg.webp|1024px]] Figure 1. Schematic diagram of liquid steel casting equipment

=== Puyang Refractories Group ===

If you want a trusted company, learn about Puyang Refractories Group. They started in 1988 in Puyang, China. The company grew from a small plant. In 2008, it became public on the Shenzhen Stock Exchange.

* Puyang Refractories Group is big in China and worldwide.
* They have 13 factories and 23 branches in many countries. These include the USA, India, Korea, Russia, Ukraine, and Serbia.
* They own five mines in China. This helps them keep their product quality high.

Here is a quick look at what they make:

Product Line Description

Purging Plug

This is their top product and is very popular in China.

Seating Block

This is one of many refractories they sell.

Castable

Used for different heating jobs.

Slide Gate Nozzle

Needed for making steel and other metals.

Black Refractories

Used when things get very hot.

MC/AMC

Special refractories for factories.

Functional Refractories

Includes nozzles, ladle bricks, and items for casting.

Silicon Nitride Bonded Silicon Carbide Bricks

Used in making aluminum.

You can trust their products. They have ISO9001:2000 and other important certificates. Puyang Refractories Group is the biggest supplier for Chinese steel companies. They make about 700,000 tons of refractories each year. If you want a company with many products and global reach, choose them.

Note: Puyang Refractories Group has a strong supply chain. Their big factories make them a good choice for large steel projects.

=== Wuxi Nanfang Refractories Company ===

Wuxi Nanfang Refractories Company has been around for a long time. It is part of Wuxi Nanfang Chemical Auxiliary Co., Ltd. The parent company has made chemicals for almost thirty years. Later, Wuxi Nanfang started making high-purity products for many uses. These include screens and new medicines.

Here is what they make and their standards:

Primary Products Quality Standards

Ladle Shroud

National high-tech company

SEN

Company that keeps promises

Rod Stopper

Grade-A Supplier for Baosteel

Slide plate gates

Purging Plugs for Ladle

Purging Plugs for BOF&EAF

Refractory for the body of the Tundish and Ladle

Wuxi Nanfang Refractories Company cares about quality. They are a Grade-A supplier for Baosteel. They are known for being reliable. If you want a company with a strong background and high-tech focus, pick them.

=== RHI China ===

RHI China is a famous name in refractories. The company started in 1999. They quickly became a leader in high-grade products. Their products are used in places with heat over 1,200°C. These places include steel, cement, metals, and glass.

Here is what they offer:

Product Offerings Description

High-grade refractory products

Used in steel, cement, metals, and glass.

Full performance-based solutions

They help from raw materials to finished products.

RHI China cares about the environment. They have a Green Mining Certificate. This means they follow green rules and local laws. In the last five years, RHI China worked with Jinan New Emei Industries Co. Ltd. They now have more products and customers. They also opened a new plant in Laiwu. This plant can make up to 80,000 tons of refractories each year.

Tip: If you want a company with new technology and green ideas, RHI China is a good choice.

=== Vesuvius China ===

Vesuvius China is part of the big Vesuvius Group. This group has a long history in refractories. Their main offices are in Suzhou, Shanghai, and Wuhan. Vesuvius China makes many products for steelmaking. These include ladle shroud, flow control products, and casting refractories.

Their products meet strict world standards like ISO 9001 and ISO 14001. This means their products are safe and high quality. Vesuvius China works with top steelmakers in China and other countries. Their global team brings new ideas to customers.

If you want a company with worldwide reach and new ideas, Vesuvius China is a great choice.

=== Henan Yangyu Refractories Co., Ltd. ===

Henan Yangyu Refractories Co., Ltd. is in Zhengzhou, Henan. The company started in 2006. They quickly became known for good quality and service. They offer [https://hyrefr.com/ko/products/ many refractory products]. These include ladle shroud, nozzles, stoppers, and slide gates.

Here is what they make and their certificates:

Product Categories Quality Certifications

ladle shroud,tundish stopper,SEN

ISO9001

sldie gate plate(LG21,CS60,1QC,LS70,Flocon4200,6300.cs80

ISO9001

ladle nozzle

ISO9001

Henan Yangyu Refractories Co., Ltd. cares about quality and safety. Their products are used in many steel plants and kilns. If you want a company with many products and high standards, consider them.

== Comparison and Selection Tips ==

[[File:60b4fd07f65b4d8c88ddc37c77b847aa.webp]] Image Source: [https://unsplash.com/ unsplash]

=== Product Quality ===

You want your steel plant to work well. Product quality is very important. Top Chinese manufacturers use strong materials. These include alumina, magnesia, and graphite. These help ladle shrouds stand up to high heat. They also make them last longer. New designs have anti-erosion linings. This makes them even stronger. Here are some common steps for quality control:

Quality Control Measure Description

Material Selection

Strong refractory materials help with high heat.

Coating Application

Smooth coatings stop sticking and help flow.

Construction Techniques

Careful mixing and setup give better strength.

Temperature Monitoring

Baking is checked often for even quality.

Regular Training

Workers get training to keep up quality and safety.

Check if a supplier uses these steps. This helps you get good ladle shroud products every time.

=== Customer Service ===

Good customer service helps you a lot. Top companies in China give technical support. They answer fast and help with setup. Some companies have teams to help you install and fix problems. Others give tips to make steelmaking better. You can get help from your first order to after-sales care.

Tip: Ask about after-sales help before you buy. Good service means less trouble later.

=== Export Experience ===

If you are outside China, you need a supplier who knows global shipping. Top companies like Puyang Refractories Group and Vesuvius China have lots of export experience. They know how to do paperwork and follow rules. This means your ladle shroud order comes on time and meets your country’s needs.

=== How to Choose ===

Choosing the right supplier can be hard. You can make it easier with a checklist:

* Check the company’s production size.
* Look at product quality and how it works.
* Make sure they have ISO 9001 or other certificates.
* Test their customer service and support.
* Read what other steel makers say.

You want a partner who gives good products and helps you. Take your time, ask questions, and pick the supplier that fits your project best.

You have learned about the top five ladle shroud makers in China. These companies are known for good quality and new ideas. They also help customers when needed. When picking a supplier, think about what you need. Ask questions to make sure they are right for you. Want to know more about ladle shroud features? Look at this easy table:

Feature Description

Material

Premium alumina-graphite or alumina-zirconia graphite

Thermal Shock Resistance

High—no preheating needed

Erosion Resistance

Special slag line design for long service life

Customization

Options for argon sealing and bell designs

Contact these companies if you want prices or more info. You can also look for more resources to find the best choice for your steel plant.

== FAQ ==

=== What is a ladle shroud used for? ===

A ladle shroud protects molten steel from air as it moves from the ladle to the tundish. You get cleaner steel and fewer defects. It also helps control the flow.

=== How do I choose the right ladle shroud supplier? ===

You should look at product quality, certifications, customer service, and export experience. Ask for samples or references. Pick a supplier who understands your needs.

=== Can I get custom ladle shrouds for my steel plant? ===

Yes! Most top suppliers offer custom designs. You can share your requirements. They will help you find the best fit for your process.

=== How long does it take to receive an order from China? ===

Delivery times vary. Usually, you can expect 2–6 weeks, depending on your location and order size. Ask your supplier for a shipping estimate.

Tip: Always confirm lead times before placing your order. This helps you plan your production schedule.

[[Category:Articles_needing_more_work]]

Tundish stopper

2025-08-10T04:54:14Z

Junhuamachinery: Created page with "[https://hyrefr.com/product/tundish-stopper/ Monoblock Stopper] (MBS) is an isostatically pressed refractory which is a critical element in the Continuous Casting of Steel where ..."

[https://hyrefr.com/product/tundish-stopper/ Monoblock Stopper] (MBS) is an isostatically pressed refractory which is a critical element in the Continuous Casting of Steel where it is used to control the flow of steel from the “Tundish to Mould”.

The stopper nose design helps to achieve desired metallurgical needs by controlling mould level fluctuation, preventing vortex formation and reduce inclusions during steel casting.

Design and quality of Monoblock Stoppers have to be customized depending on the operational requirement of the steel plant. Monoblock Stoppers for high sequence casting have projected slag zone and special mix reinforcement for slag zone area.

Argon purging arrangement in MBS help to prevent air ingress and re-oxidation of steel and formation of clogging deposits.

[[Category:Definitions]]

Ladle shroud

2025-08-05T10:27:32Z

Junhuamachinery: Created page with "The major roles of the [https://hyrefr.com/product/ladle-shroud/ Ladle Shroud] : * To protect the steel stream from re-oxidation between the ladle and tundish * To introduce the..."

The major roles of the [https://hyrefr.com/product/ladle-shroud/ Ladle Shroud] :

* To protect the steel stream from re-oxidation between the ladle and tundish
* To introduce the steel into the tundish with minimum risk of tundish powder entrapment

These roles are essential for most of the steel grades and steel applications. 
HYRE teams combine their respective skills and experience in material selection and refractory design to offer a wide range of custom-tailored Ladle Shrouds and Gaskets that can fit each steel producer’s needs.

[[Category:Definitions]]

User:Junhuamachinery

2025-08-05T10:24:44Z

Junhuamachinery:

More than 15years experience in the flow control refractory manufacturing.

We,[https://hyrefr.com/ Henan Yangyu Refractories Co.,Ltd,]established in 2008,is specialized in the flow control refractory with the total 150 staffs,including professional technical supporting team of 15 engineers,3senior engineers, covering more than 2000 square meters.We mainly manufacture slide gate plate,ladle nozzle,[https://hyrefr.com/product/ladle-shroud/ Isostatic refractory],and exporting more than 15countries,such as Italy,Vietnam,Russia,Turkey.[https://hyrefr.com/wear-reason-about-the-slide-gate-plate/ Slide Gate Plate] is a critical component in the continuous casting process, used to [https://hyrefr.com/ control the flow] of molten steel from the ladle or tundish to the crystallizer. The following is a detailed description:

2021-04-04T13:51:26Z

Junhuamachinery: concrete pump clean ball

concrete pump clean ball

Shotcrete technology

2021-03-31T07:11:59Z

Junhuamachinery:

[[File:Shotcrete.jpg|link=File:Shotcrete.jpg]]

= Introduction =

[https://www.junhuamachinery.com Shotcrete] is a mortar or high performance concrete conveyed through a hose and pneumatically projected at high velocity onto a backing surface. It is the force of this spraying action that leads to compaction of the concrete or mortar which then forms layers of concrete to the required thickness .

ShotcretingShotcreting has proved to be the best method for construction of curved surfaces. Tunnel linings and domes are now much easier to construct with the advent of with shotcrete technology.

Shotcrete is a widely accepted and used way of placing material that is cementitious in nature for a vast variety of applications.

Since 1900, the year it was invented by American taxidermist Carl Akeley, it has seen many improvements, be it in the equipment or in the specialised techniques required for the pneumatic application of mortar or concrete.Akeley, it has seen many improvements, be it in the equipment or in the specialised techniques required for the pneumatic application of mortar or concrete.

Today it has become a vital material because of it being versatile in shape, high strength, durable, good bonding ability, and in areas of difficult access it can be easily sprayed onto a surface at high velocity, making it handy for operation.

Its applications range from slope and surface protection, to renovating existing structures.

Shotcrete is applied to a lacerated surface, usually for reasons such as to safeguard a surface which, when left untreated, would erode or which is unstable due to fracturing and defects.

In the mining sector, the demand for shotcrete for underground support has skyrocketed in recent years. The simultaneous working of multiple heading, unusual filling conditions and difficulty in access are some of the problems which are distinctive to underground mining and which require new and innovative applications of shotcrete technology.

= Applications =

The selection of shotcrete for a particular application should be based on knowledge, experience, and a careful study of required and achievable material performance. The success of the shotcrete for that application is contingent upon proper planning and supervision, plus the skill and continuous attention provided by the shotcrete applicator.

== Repair ==

Shotcrete can be used to repair the damaged surface of concrete, timber, or steel structures provided there is access to the surface needing repair. The following examples indicate a few ways in which shotcrete can be used in repairs:

=== Bridges ===

Shotcrete repair can be used for bridge deck rehabilitation, but it has generally been uneconomical for major full-thickness repairs. It is very useful, however, for beam repairs of variable depths ,caps, columns, abutments, wing walls, and under decks from the standpoint of technique and cost.

=== Buildings ===

In building repairs, shotcrete is commonly used for repair of fire and earthquake damage and deterioration, strengthening walls, and encasing structural steel for fireproofing. The repair of structural members such as beams, columns, and connections is common for structures damaged by an earthquake.

=== Marine structure ===

Damage to marine structures can result from deterioration of the concrete and of the reinforcement. Damaging conditions are corrosion of the steel, freezing and thawing action, impact loading, structural distress, physical abrasion from the action of waves, sand, gravel, and floating ice, and chemical attack due to sulfates.

These problems can occur in most marine structures such as bridge decks, piles, pile caps, beams, piers, navigation locks, guide walls, dams, powerhouses, and discharge tunnels. In many cases, shotcrete can be used to repair the deteriorated surfaces of these structures.

=== Spillway surfaces ===

Surfaces subject to high velocity flows may be damaged by cavitation erosion or abrasion erosion. Shotcrete repairs are advantageous because of the relatively short outage necessary to complete the repairs

== Underground excavation ==

For the most part, shotcrete is used in underground excavations in rock; but on occasion, it has been successfully used in the advancement of tunnels through altered, cohesion-less, and loose soils.

Typical underground shotcrete applications range from supplementing or replacing conventional support materials such as lagging and steel sets, sealing rock surfaces, channeling water flows, and installing temporary support and permanent linings.

== Slope and surface protection ==

Shotcrete is often used for temporary protection of exposed rock surfaces that will deteriorate when exposed to air.

Shotcrete is also used to permanently cover slopes or cuts that may erode in time or otherwise deteriorate. Slope protection should be properly drained to prevent damage from excessive uplift pressure.

Application of shotcrete to the surface of landfills and other waste areas is beneficial to prevent surface water infiltration.

== New structures ==

Shotcrete is not necessarily the fastest method of placing concrete on all jobs, but where thin sections and large areas are involved, shotcreting can be used effectively to save time. The following paragraphs describe some of the applications involved with construction of new structures.

=== Pools and tanks ===

Shotcrete has been used extensively to construct concrete swimming pools. More recently, large aquariums have been constructed using shotcrete.

=== Shotcrete floors and walls ===

Shotcrete floors in tanks and pools on well compacted sub-base or on undisturbed earth have generally given excellent service.

Vertical and overhead construction for walls, slabs, columns, and other structural members has been frequently shotcreted.

=== Shotcrete domes ===

Construction techniques using inflatable air-forming systems have made the construction of shotcrete shells or domes practical. These large structures have been used for residential housing, warehousing, bridge, and culvert applications.

= Shotcrete materials =

Cement, water, sand and aggregate are the basic materials used in shotcrete along with various plasticisers and admixtures to enhance its functioning. High water-cement ratio gives slow setting and influences end quality, while moisture content in sand/aggregate is also keenly measured. Optimal W/C ratio is around 0.45.

Composition of sand/aggregate depends upon water demand, workability, accelerators, rebound, shrinkage and durability.

== Cementitious materials ==

=== Portland cement ===

Cement requirements for shotcrete are similar to those for conventional concrete.

Low-alkali cement must be specified when the aggregates used are regarded as chemically reactive with the alkalies in the cement.

Air-entraining cement has been used with the wet-mix process and has achieved varied results, with the air content generally much lower than in conventional concrete. Generally, the use of air-entraining cement is not recommended, since in-place air contents are affected by external factors such as air pressure, hose lengths, and equipment type.

When added to a Portland cement matrix, pozzolan reacts with the calcium hydroxide and water to produce more calcium silicate gel.

=== Water ===

* Mixing water: Potable water should be used. In this is not available, the proposed water source should be tested.
* Curing water: No special requirements are necessary for curing water applied to shotcrete. Water for curing of architectural shotcrete should be free from elements that will cause staining.

=== Aggregate ===

Lightweight aggregate shotcrete is most practical for the dry-mix process. Since moisture and aggregate contact is initiated at the nozzle, the severe workability reductions common in conventional lightweight concrete production do not occur.

=== Reinforcing steel ===

Reinforcing bars for shotcrete should meet the same specifications as for conventional concrete. Because of the placement method, the use of bars larger than 16 mm diameter or heavy concentrations of steel are not practical.

Large bars make it difficult to achieve adequate build-up of good quality shotcrete behind the bar and heavy concentrations of steel interfere with the placement of shotcrete. In general, bar spacings of 150 mm to 300 mm are recommended for shotcrete reinforcement.

=== Chemical admixtures ===

Because of shotcrete equipment limitations, the use of admixtures in shotcrete is not the same as in conventional concrete. Admixtures should be tested in the field prior to use on large jobs to ensure that the desired properties are achieved. Chemical admixtures used in shotcrete should comply with the appropriate requirements.

= Properties of shotcrete =

As is the case with conventional concrete, shotcrete properties vary dramatically depending on water-cement ratio, aggregate quality, size, and type, admixtures used, type of cement used, and construction practices.

The proper use of admixtures, fibers, silica fume, and polymers can improve certain properties. Depending on the needs of the particular application, properties of the shotcrete materials and mixtures should be tested prior to final application.

== Strength ==

In terms of compressive and flexural strength, shotcrete can produce strength generally equivalent to conventional concrete. Compressive strengths of between 30 and 60 N/mm² is generally achievable.

Relationships between water-cement ratio and strength follow normal patterns, with higher strength associated with lower water-cement ratios.

== Bond strength ==

Although few data on bond strength appear to exist, bond strength with other materials is reported to be generally higher than can be achieved with conventional concrete.

== Shrinkage ==

Drying shrinkage is most influenced by the water content of the mixture. Typical values of unrestrained shrinkage range from 600 to 1,000 millionths. Shrinkage is reduced in coarse aggregate shotcrete and increased in shotcrete without coarse aggregate or shotcrete subject to high rebound.

Shotcrete containing silica fume has a tendency to exhibit more shrinkage before setting than shotcrete without silica fume.

== Toughness ==

The addition of fibers to shotcrete can result in a product displaying significant load carrying capability after the occurrence of the first crack. The relationship of post-crack load capacity to load capacity at first crack is defined as toughness.

The type, size, shape, and amount of fiber determines the extent of this performance. The use of the toughness index by load-deflection testing, provides a rational means of specifying and comparing performance. However, recent concerns have developed over the specifics of applying this testing procedure (Gopalaratnam et al. 1991).

= Equipment used =

== Batching and mixing equipment ==

Most shotcrete is batched and mixed in the field using portable mixing equipment or delivered in mixer trucks from a local ready-mixed concrete plant. Mixing equipment for shotcrete is of the batch or the continuous type.

In the continuous type, individual ingredients are fed to a mixer screw by means of variable speed augers, belt-feed systems, or a combination of both. A hopper is sometimes used in high production units to collect and feed the mixture as required. Water-metering systems are also available to re-dampen the mixture. Batching and mixing equipment must be capable of maintaining an adequate and continuous flow of homogeneous material.

Batching by mass is preferred and will normally be required. Water may be batched by mass or volume. For small jobs, approval may be given to batching by a volumetric container, provided periodic weight checks are made since many shotcrete jobs have a low production rate and are in isolated locations, mixing is often done by a small drum mixer at the jobsite.

== Admixer dispenser ==

Admixtures may be added when needed during mixing or at the nozzle, depending on their properties and the type of shotcrete process (dry or wet).

In the dry-mix process, dry (powder) admixtures are usually introduced into the mixture during batching. If a continuous feed gun is being used, they may also be added directly into the gun hopper by a special dispenser, usually an auger-type dry dispenser driven by and calibrated to the gear train of the shotcrete machine. The dispenser should be capable of metering a precise quantity of admixture, usually 1 to 4 % by mass of the cement, into the mixture, and must be capable of accurately varying the ratio of accelerator to cement.

In the dry-mix process, liquid admixtures must be introduced at the nozzle through the mixing water. The admixture may be premixed with water and pumped to the nozzle or added directly to the mixing water at the nozzle.

In the wet-mix process, dry or liquid admixtures may be added to the mixture when batching provided the pumping properties are not adversely altered. As an example, an accelerator would create problems if added during batching, while a high-range water reducing admixture (HRWR) might have beneficial effects. In wet-mix applications, only liquid admixtures may be added to the air supply at the nozzle. They are proportioned to the delivery rate of the mixture through the material hose.

== Air compressor ==

A properly operating air compressor of ample capacity is essential to a satisfactory shotcreting operation. The compressor should maintain a supply of clean, dry, oil-free air adequate for maintaining sufficient nozzle velocity for all parts of the work while simultaneously operating all air-driven equipment and a blowpipe for cleaning away rebound.

== Nozzle ==

A dry-mix nozzle typically consists of a tip, water ring, control valve, and nozzle body arranged in a wide variety of nozzle tips, nozzle sizes, and configurations. Some investigations have shown improved mixing action and less rebound for dry-mix shotcrete when a special pre-wetting nozzle is used and the water ring is placed in the hose 1 to 8 feet before of the nozzle. This has been particularly effective for silica fume shotcrete.

= Proportioning of shotcrete =

== Consideration ==

In general, conventional concrete technology may be applied to shotcrete proportioning. Prior to mixture proportioning, the following should be considered:

* Type of dry-mix or wet-mix shotcrete appropriate for the work.
* The specific job constraints on the shotcrete work.
* The type of specification: Performance versus prescription, or contractor versus government mixture.

== Mixture proportioning trial batching ==

Since shotcrete performance is highly dependent on application procedures, trial batching and testing is a critical operation in verifying mixture performance. The batching and mixing of wet-mix shotcrete is practically identical to conventional concrete; only the fabrication of specimens is different. However, dry-mix is a distinct process.

It is normal procedure to obtain trial mixture proportions for shotcrete from the contractor. Along with the proportions, test panels and cores of the shotcrete are highly recommended,.

Test panels are particularly important for dry-mix shotcrete because laboratory mixtures cannot duplicate as-shot dry-mix shotcrete. Typically, a performance specification of 12-hour, 7-day and/or 28-day compressive strengths will be specified, along with a grading for the aggregate. Both the wet- and dry-mix methods will yield a higher as-shot cement content and lower coarse aggregate content, due to rebound of the aggregate.

== Nominal maximum size aggregate (NMSA) ==

The NMSA depends on several factors. The selection major factors are the allowable shrinkage performance, size of the placement, and the rigidity of the substrate. The amount of rebound, inherent in the shotcrete process, depends on the ability of the substrate and the placed shotcrete to cushion subsequently placed shotcrete.

Shotcrete for thin linings on rock or concrete experiences high rebound. Thicker sections and sections on soil structures experience lower rebound. For placements of thin layers on hard surfaces, coarse aggregate should be minimised or eliminated in the mixture to minimise rebound.

== Wet mix proportioning ==

Mixture proportioning procedures for the formulation of conventional concrete for pumping applications are applicable for wet-mix shotcrete. The nominal aggregate size is usually 10 mm. The batched cement content will typically range from 350 to 450 kg/m³.

Rich mixtures are common for shotcrete, especially if vertical or overhead shotcrete placement is required. The limiting factor for cement content in a mixture is often governed by the amount of cement necessary for the shotcrete to adhere to a wall or ceiling, not the specified compressive strength.

== Dry mix proportioning ==

There is no established method of proportioning dry-mix shotcrete. Since it is not practical to perform laboratory trial mixtures for dry-mix shotcrete, field testing of dry-mix proportions is highly advisable, especially if no field data exist for a given dry-mix. The in-place aggregate grading will be finer than the batched grading due to rebound, especially if larger aggregate sizes are used. As with wet-mix shotcrete, the in-place cement factor will be higher also.

= Comparison between dry-mix process and wet-mix process =

Shotcrete suitable for most requirements can be produced by either the dry-mix or wet-mix process. However, differences in the equipment cost, maintenance requirements, operational features, placement characteristics, and product quality may make one or the other more attractive for a particular application.

Bond strengths of new shotcrete to existing materials are generally higher with dry-mix shotcrete than with wet-mix shotcrete. Both shotcrete mixtures often provide significantly higher bond strengths to existing materials than does conventional concrete.

Typically, dry-mix shotcrete is applied at a much slower rate than wet-mix shotcrete. Dry-mix shotcrete is often applied at a rate of 1 or 2 cubic yards per hour compared to wet-mix shotcrete applied at a rate of up to 7 or 8 cubic yards per hour. Depending on the application, the in-place production rate may be significantly lower because of obstacles, rebound, and other features which may cause delays.

Rebound is the shotcrete material that 'bounces' off the shooting surface. Rebound for conventional dry-mix shotcrete, in the best of conditions, can be expected to be at least 20% of the total material passed through the nozzle. Wet-mix shotcrete rebounds somewhat less than dry-mix shotcrete.

The use of air-entraining admixtures (AEA) in shotcrete is practical only in wet-mix shotcrete. When batched properly, AEA forms an air-void system suitable for providing frost resistance to wet-mix shotcrete. The formation of an air-void system in dry-mix shotcrete is not possible.

= Related articles on Designing Buildings Wiki =

* Basement waterproofing.
* Cement.
* Concrete superplasticizer.
* Portland cement.
* Precast concrete.
* Prestressed concrete.
* Reinforced concrete.
* Self-compacting concrete.
* Shotcrete global market.
* Tunnelling.

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