What are the Applications of Shotcrete?
- Repair and Restoration. Shotcrete is a technique for repairing and restoring deteriorated concrete, steel, or wood structures.
- Ground Support. In combination with various reinforcements and anchors, shotcrete effectively stabilizes earth and rock excavations and supports the ground during mining and tunneling.
- New Construction. ...
- Refractory. ...
What is the difference between shotcrete and gunite?
What is the difference between shotcrete and Gunite? Shotcrete is an all-inclusive term to describe the spraying of concrete or mortar that may be accomplished through either a dry- or wet-mix process. Gunite refers only to the dry-mix process in which the dry cementitious mixture is blown through a hose to the nozzle, where the water is ...
What is shotcrete and how is it applied?
shotcrete, also called (trademark) Gunite, concrete applied by spraying. Shotcrete is a mixture of aggregate and portland cement, conveyed by compressed air to the nozzle of a spray gun, where water is added. The wet mixture is then sprayed in place and may be carved or troweled almost immediately. For structural uses, shotcrete is usually applied over a framework of reinforcing bars and steel ...
How much does it cost have shotcrete installed?
How much does shotcrete cost? The costs of shotcrete per square foot all depend on the contractor you choose, your geographical location and the scope of the job. For pool jobs, the costs of hiring a professional contractor, from multiple quotes we found via online forum threads, can range anywhere from $125 to $195 per yard , again, all ...
What is the square foot price of shotcrete?
The costs of shotcrete per square foot all depend on the contractor you choose, your geographical location and the scope of the job. For pool jobs, the costs of hiring a professional contractor, from multiple quotes we found via online forum threads, can range anywhere from $125 to $195 per yard , again, all depending on the scope of the job.
What is the purpose of shotcrete?
Shotcrete is used to reinforce both temporary and permanent excavations. It may be employed, in concert with lagging and other forms of earth anchor, to stabilize an excavation for an underground parking structure or hi-rise buildings during construction.
What type of concrete is shotcrete?
Gunite Types: Dry Shotcrete or Wet Shotcrete Gunite is the popular trade term for dry-gun concrete, while shotcrete is the common term for wet-gun concrete. With the gunite method, the dry concrete ingredients are placed into a hopper and then pushed out pneumatically through a hose to a nozzle.
Is shotcrete stronger than concrete?
The impact velocity of properly applied shotcrete instantly compacts the material, yielding an “in-place” mix that is richer in cement and higher in strength than the same mixture prior to placement.
What is the mix for shotcrete?
Shotcrete typically consists of one part cement and four parts sand by weight with approximately 7% water by mass of dry ingredients.
What material is used in shotcrete?
Shotcrete is a mixture of aggregate and portland cement, conveyed by compressed air to the nozzle of a spray gun, where water is added. The wet mixture is then sprayed in place and may be carved or troweled almost immediately.
What are the advantages of shotcrete?
Shotcrete has all of the advantages of standard concrete materials, such as its high tensile strength, durability, fire retardation, low permeability, and thermal efficiency.
How thick can shotcrete be applied?
There is no stated maximum thickness for shotcrete used in shear walls or any other type of wall. Walls have been successfully placed to a thickness of 36 in. (914 mm) for some time. The two main concerns are the heat of hydration and proper encapsulation of the reinforcing steel.
How long does it take for shotcrete to dry?
Concrete, when applied using the shotcrete process, or cast-in-place, needs to cure for 7 days. Water is the best curing method (7 continuous days).
What type of concrete is used in pools?
The use of gunite or shotcrete is typically your pool builder's choice.
What is the density of shotcrete?
Typically using barites the density will be in the region of 3,500kg/m3, which is 45% greater than that of normal concrete [4].
How do you calculate shotcrete quantity?
Multiply the total square feet times the thickness of the floors and walls. For example, if your walls are 300 feet square and 8 inches thick ( 8 inches converted to feet is . 75), multiply 300 times . 75, and you have the total cubic feet of concrete to be poured.
What is the code for shotcrete?
IS 9012The current Indian shotcrete code, IS 9012 is not adequate to fulfil the requirement of the present scenario of sprayed concrete construction. The details about the mix design, usage of fibers, long term durability and standard testing procedures for shotcrete are deficient.
What is difference between shotcrete and concrete?
Shotcrete is pretty much the same thing as concrete (i.e. it is used ready mixed), but its name derives from the way it is applied. Instead of being poured, it is fired out of a hose at high speed (you can see how it gets its name!).
What is spray concrete?
Sprayed concrete is the method by which concrete is sprayed into place, rather than the more conventionally used pouring or placing into formwork. According to the Sprayed Concrete Association other terms used include Gunite, Shot Concrete and Shotcrete. There are many applications and uses for sprayed concrete.
How do you make concrete underwater?
0:123:37Underwater Concreting || Placing of Concrete - YouTubeYouTubeStart of suggested clipEnd of suggested clipIn the bottom dump bucket concrete is taken through the water in a watertight. Box or bucket. OnceMoreIn the bottom dump bucket concrete is taken through the water in a watertight. Box or bucket. Once it is reached to the final place of deposition.
How is under water concreting carried out?
Tremie Method of Underwater Concreting The concrete is moved to the hopper by either pumping, belt conveyer or skips. Tremie pipe, which upper end connected to a hopper and lower end continuously submerged in fresh concrete, is used to place concrete at the exact location from a hopper at the surface.
What is shotcrete concrete?
Shotcrete is the process of placing concrete to achieve high strengths and low permeability. American Concrete Institute's (ACI) "Guide to Shotcrete" defines Shotcrete as concrete (or sometimes mortar) conveyed through a hose and pneumatically projected at high velocity onto a receiving surface. While the material component ...
What industries use shotcrete?
The shotcrete process is popular in many industries: pools, theme parks, underground tunneling, skate parks and retaining walls. Products made from using shotcrete are all around us but rarely noticed.
What is the best way to put concrete on a surface?
Spraying concrete onto a surface at high velocity is, in theory, the perfect concrete placement method. Individual aggregate particles of various sizes, coated with cement paste, are driven into place to form a void free mass of fully compacted concrete. This strong, dense, well bonded material is ideal for most concrete applications, including decorative concrete.
Is shotcrete good for pools?
One sided forming with unlimited shape potential makes shotcrete a perfect material for pools. Residential home construction, renovations and commercial projects can all take advantage of the shotcrete process for retaining walls, faux rock finishes, decking or high-rise facades.
Can shotcrete be used for underground rail tunnels?
Many underground rail tunnels are using shotcrete as the finished exterior coating, not just rock and ground support. This process doesn't just satisfy the structural specifications of a project but also greatly reduces the cost of a project. One sided forming with unlimited shape potential makes shotcrete a perfect material for pools.
Is shotcrete water repellent?
Walt Disney Worlds Splash Mountain and Big Thunder Mountain Railroad have structural and decorative concrete applied through the shotcrete process. Since shotcrete is very dense, its low porosity and low permeability make it a very water repellent product, ideal for theme parks.
How is shotcrete applied?
Shotcrete is applied using a wet- or dry-mix process. The wet-mix shotcrete process mixes all ingredients, including water, before introduction into the delivery hose. The dry-mix shotcrete process adds water to the mix at the nozzle.
Who is 506 Shotcreting?
506, Shotcreting. He is a liaison member for ACI and the Brazilian Concrete Association (now IBRACON). A board and committee member of IBRACON, he served as President from 1997 to 1999. Awards received include the IBRACON Honorary Membership in 2001; the Ary Torres Award in 2002, as outstanding c...
Is shotcrete the same as cast in place concrete?
Although the hardened properties of shotcrete are similar to those of conventional cast-in-place concrete, the nature of the placement process results in an excellent bond with most substrates, and rapid or instant capabilities, particularly on complex forms or shapes.
What is shotcrete?
Shotcrete is a possible alternative to superstructure repair (unstructured) and substructure repair ( unstructured ).
When to use shotcrete?
Shotcrete is used in situations where the formwork is cost-prohibitive or impractical.
What is shotcrete mortar?
Shotcrete is a mixture of cement, aggregates, and water that is usually reinforced by conventional steel rods, steel mesh, or fiber.
Why is shotcrete better than concrete?
Why shotcrete is preferred: Shotcrete is more economical than conventional concrete because it requires less formwork. It only requires a small space for construction and its location. In the case of the shotcrete, cement content is high, so it is durable. It is resistant to fire, disasters, mold, worms and also has low permeability.
What is shotcreting unit?
Shotcreting is performed with the special unit, which consists of a mortar gun or concrete sprayer and a compressor.
How is cement mixed?
In the dry-mix process, cement, aggregate, and admixture are mixed together, conveyed pneumatically through a tube and then through a water ring in the nozzle.
What is wet mix?
In wet-mix process: cement, aggregates, mixtures, and water are mixed together before being ductile and aerated. Typically, a concrete truck supplies a wet-mix and is pumped through a shotcrete rig for placement. The wet-mixes are used for large quantities of placements with easy accessibility to construction automobiles.
Where is shotcrete used?
Shotcrete is commonly used to line tunnel walls, in mines, subways, and automobile tunnels. Fire-resistant shotcrete developed in Norway is used on the Marmaray tunnel in Istanbul.
What is shotcrete machine?
Shotcrete machines are available which control the complete process and make it very fast and easy. Manual and mechanical methods are used for the wet spraying process but wet sprayed concrete is traditionally applied by machine. The high spray outputs and large cross-sections require the work to be mechanised. Concrete spraying systems with duplex pumps are mainly used for working with wet mixes. Unlike conventional concrete pumps, these systems have to meet the additional requirement of delivering a concrete flow that is as constant as possible, and therefore continuous, to guarantee homogeneous spray application'.
What is shotcrete in pool construction?
In pool construction, however, shotcrete refers to wet mix and gunite to dry mix. In this context, these terms are not interchangeable.
Why is shotcrete used in mining?
Shotcrete is very useful in hard rock mining. Development of decline pathway to go underground is critical for movement of heavy machinery, miners, and material. Shotcrete helps make these paths safe from any ground fall.
What is cement gunite?
Gunite was originally a trademarked name that specifically referred to the dry-mix pneumatic cement application process. In the dry-mix process, the dry sand and cement mixture is blown through a hose using compressed air, with water being injected at the nozzle to hydrate the mixture, immediately before it is discharged onto the receiving surface. Gunite was the original term coined by Akeley, trademarked in 1909 and patented in North Carolina. The concrete mixture is applied by pneumatic pressure from a gun, hence "gun"-ite.
What is wet mix shotcrete?
Wet-mix shotcrete involves pumping of a previously prepared concrete, typically ready-mixed concrete, to the nozzle. Compressed air is introduced at the nozzle to impel the mixture onto the receiving surface. The wet-process procedure generally produces less rebound, waste (when material falls to the floor), and dust compared to the dry-mix process. The greatest advantage of the wet-mix process is all the ingredients are mixed with the water and additives required, and also larger volumes can be placed in less time than the dry process concrete.
What is a duplex concrete pump?
Concrete spraying systems with duplex pumps are mainly used for working with wet mixes. Unlike conventional concrete pumps, these systems have to meet the additional requirement of delivering a concrete flow that is as constant as possible, and therefore continuous, to guarantee homogeneous spray application'.
What is shotcrete concrete?
Shotcrete is a specific type of concrete that can either be dry-mix or wet-mix. It’s become known for its unique application process that differs from traditional concrete.
What is the difference between shotcrete and concrete?
The major difference between shotcrete and its close cousin, concrete, is the placement method. Concrete is discharged from a ready-mix truck, placed on the ground or in forms and then must be vibrated for compaction. By contrast, the shotcrete process, whether using wet or dry material feed, does not require forming or compaction thereby enhancing ...
What Are the Advantages of Shotcrete & Concrete?
Concrete is more advantageous to use for a larger area, such as the foundation of a building. The mixture is poured into any framed area and left to harden.
What is a dry mix shotcrete?
Dry-mix process shotcrete introduces and mixes the required water at the application nozzle as the dry cementitious materials (fly ash, slag, silica fume etc.) and aggregates are delivered through the “gun” The nozzleman controls mix consistency, adjusting water addition to suit the changing conditions of the work area.
What is the most important factor in concrete mix design?
Just as in concrete mix designs, the ratio of the water-to-cementitious material remains the single most important parameter influencing the compressive strength, shrinkage and overall durability of the final product. Application technique is also crucial and less forgiving than ordinary ready-mix.
What should the final concrete placement selection be based on?
While it is true that one approach may be more applicable, adaptable or economical than another, the final concrete placement selection for the project should be based on project design, material performance criteria and overall budget.
What is concrete made of?
It consists of fine rocks mixed with water and paste that hardens.
What is Shotcrete
Shotcrete is a method of applying concrete to a vertical or above surface by projecting it at a high velocity.
Guniting
Guniting is a method of applying mortar or concrete to a surface by pushing it at a high velocity through a hose or spray gun.
Advantage of Shotcrete Concrete
Shotcreting creates a solid and consistent coating of concrete on the surface.
Application of Shotcrete
It was utilised in tunnels, mines, drainage audits, and exploitative audits to open underground apertures.
