What is the difference between Concrete & Shotcrete ? - Part 3

 What is the difference between Concrete & Shotcrete ? - Part 3

What is the difference between Concrete & Shotcrete ?

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. Typically, a fine aggregate dry-mix shotcrete mix delivered in a 1:3 cement to aggregate proportion upon entering the application gun results in a 1:2 cement to aggregate ratio when in place. What appears to be a waste of materials and a dust nuisance known in the trade as “rebound” and overspray, actually results in dense, high-strength shotcrete as a portion of the aggregate ricochets off the receiving surface and away from the placement location. The loss through rebound will vary depending upon the dryness of the mix, the shooting distance from the surface, wind conditions, etc. The intended thickness is generally overshot, trimmed back to the design thickness and finished to the desired surface texture and appearance.

What is the difference between Concrete & Shotcrete ?

While the dry mix process sounds quick and economical, it requires precautions to ensure application quality. The nozzleman’s workmanship and experience are critical, since the nozzleman controls the critical water-to-mix ratio going into application equipment. With the wet-mix process, the nozzleman has no control over the consistency of the mix delivered to the job site, but can control the velocity of the materials and the addition of accelerators as the mix leaves the nozzle.




The other 3 Parts of the topic :

Part 1

Part 2

Part 4

What is the difference between Concrete & Shotcrete ? - Part 2

What is the difference between Concrete & Shotcrete ? - Part 2

What is the difference between Concrete & Shotcrete ?

Shotcrete, was originally called “Gunite” when Carl Akeley designed a doubled chambered cement gun in 1910. His apparatus pneumatically applied a sand-cement mixture at a high velocity to the intended surface. Other trademarks were soon developed known as Guncrete, Pneucrete, Blastcrete, Blocrete, Jetcrete etc. all referring to pneumatically applied concrete. Today Gunite equates to dry-mix process shotcrete while the term “shotcrete” usually describes the wet-mix shotcrete process. At point of application, both are typically referred to as shotcrete.

What is the difference between Concrete & 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. The dry-mix process also is well suited for sporadic application operations since the majority of the water only comes into contact with the cementitious materials as it leaves the nozzle.The wet-mix process utilizes concrete delivered to the job that is thoroughly mixed excluding of any required accelerators. The ingredients are generally delivered in ready-mix trucks as with normal concrete. Accelerators or other admixtures may still be metered into the slurry at the nozzle along with air under pressure to increase the velocity of the material and improve control of the application or “shooting” process.



The other 3 Parts of the topic :

Part 1

Part 3

Part 4

What is the difference between Concrete & Shotcrete ? - Part 1

 What is the difference between Concrete & Shotcrete ? - Part 1

What is the difference between Concrete & Shotcrete ?

Concrete is truly a versatile building material. Concretes in use today are formulated with very specific performance characteristics in mind and include lightweight, heavyweight, porous, fiber-reinforced, mass, high-performance and cellular concretes to name just a few. Each provides specific characteristics or properties for their intended use. These properties are achieved by intentional formulation and control of such variables as cement content and type, pozzolan type and content, aggregate type, admixtures used, the addition time and rate of those admixtures, as well as other, often subtle, differences.

What is the difference between Concrete & Shotcrete ?

One widely used specialty concrete is known as “shotcrete.” 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 design creativity and application flexibility, often resulting in a savings of time or money.



The other 3 Parts of the topic :

Part 2

Part 3

Part 4

What is Concrete ?

What is Concrete ?

All about Concrete , pouring Concrete & Reinforced Concrete

Concrete is a composite construction material composed of cement (commonly Portland cement) and other cementitious materials such as fly ash and slag cement, aggregate (generally a coarse aggregate made of gravels or crushed rocks such as limestone, or granite, plus a fine aggregate such as sand), water, and chemical admixtures.

 

The word concrete comes from the Latin word "concretus" (meaning compact or condensed), the perfect passive participle of "concresco", from "com-" (together) and "cresco" (to grow).

Concrete solidifies and hardens after mixing with water and placement due to a chemical process known as hydration. The water reacts with the cement, which bonds the other components together, eventually creating a robust stone-like material. Concrete is used to make pavements, pipe, architectural structures, foundations, motorways/roads, bridges/overpasses, parking structures, brick/block walls and footings for gates, fences and poles.

Concrete is used more than any other man-made material in the world. As of 2006, about 7.5 cubic kilometres of concrete are made each year—more than one cubic metre for every person on Earth.

All about Concrete , pouring Concrete & Reinforced Concrete

Concrete powers a US$35 billion industry, employing more than two million workers in the United States alone. More than 55,000 miles (89,000 km) of highways in the United States are paved with this material. Reinforced concrete, prestressed concrete and precast concrete are the most widely used types of concrete functional extensions in modern days.