Sprayed Concrete – Efficient Construction Techniques

Introduction

In the fast-moving world of construction today, time-effective means of construction that do not hamper quality are highly sought after. One of the most fun and widely utilized methods is Sprayed Concrete.

More widely known as shotcrete, sprayed concrete is currently one of the most efficient construction methods available. Sprayed concrete is concrete that is conveyed through a hose and pneumatically projected (sprayed) at a high velocity onto a particular surface.

It allows construction to proceed at a faster rate while improving bonding to the substrate, which is an effective method of working with intricate structures and irregular surface materials.

Over the years, sprayed concrete has grown outside of a traditional placement method, due to an increase in equipment, materials, and chemical admixtures.

Sprayed concrete has established itself as a method of construction through varied applications, including but not limited to tunnel linings, retaining walls, slope stabilization, and swimming pools.

Next, we will consider the factors that make sprayed concrete so effective and popular in the construction world today.

Benefits of Sprayed Concrete

The use of sprayed concrete offers nearly all of the advantages of traditional methods of concrete placement, plus and in compared to methods of traditional placement, several other significant benefits:

Speed of Application: Sprayed concrete allows for the ultimate speed in placement of concrete, which allows to be placed quickly over large irregular surfaces which can greatly reduce the overall time required for construction.

Reduced Formwork: Unlike normal concrete, applied concrete generally does not need multiple formwork applications. This means lower material costs and reduced labor costs.Excellent

Anchor Strength: The material is applied with high velocity which causes strong anchoring to the area beneath the applied concrete, which enables it to be used in repair works or as an additional layer.

Versatile Applications: It can be applied to vertical and overhead surfaces without sagging, which makes it applicable to a wider range of applications.

Increased Durability: When combined with appropriate admixtures and reinforcements, applied concrete can have superior durability, chemical resistance, and low permeability.

Reduction of Rebound Loss: Improvements in admixtures and equipment have resulted in improved material delivery, which reduces loss during application, improving overall material efficiency.

Sprayed Concrete Applications

The versatility of sprayed concrete allows it to be applied in a variety of applications:

1. Tunnel Linings: have been extensively used in tunnel construction as initial ground support as well as permanent linings.

2. Self-Supported Slope Stabilization: can be used in steep slope and embankments to reinforce soil and help stabilize slopes and embankments to prevent landslides.

3. Retaining Walls: can be used to construct and reinforce a retaining structure.

4. Swimming Pools: are great for forming complex shapes and designs where no specific formwork can be used.

5. Repair and Rehabilitation: used to effectively repair concrete structures by applying a strong overlay.

6. Mining: Used as immediate ground support in an underground mine or shaft.

Requirements for Sprayed Concrete

To achieve maximum performance & life cycle, sprayed concrete must fulfill several essential criteria:      

1. Workability: The concrete needs to have a sufficient workability to allow efficient pumping & spraying.

2. Adhesion: The concrete must bond with the substrate to have integrity as a material.

3. Strength: The compressive, tensile & flexural strengths must meet design specifications.

4. Durability: The resistance of water, chemicals & temperature to which it is exposed is critical.

5. Reduced Rebound: Reducing the rebound (material that bounces off the surface during spraying) will provide efficient use of materials and a high-quality finish.       

Often, to get these properties, it will require specific concrete admixtures for improvements of the concrete mix properties that were previously discussed.

Chemical Solutions from Sakshi Chem Sciences for Sprayed Concrete

Sakshi Chem Sciences provides high-performance chemical admixtures for the specific needs of sprayed concrete. These products will enhance workability, strength, bonding & durability, desired in a sprayed concrete setting.

Superplasticizers

PCE POWDERA Polycarboxylate Ether (PCE) based superplasticizer powder is a highly effective water reducing agent that will effectively improve the workability of sprayed concrete, at very little expense in strength. In addition it allows a high flow for ease of pumping & spraying of concrete.

Benefits:

• Excellent retention in slump.
• Low dosage need.
• Improved adhesion and segregation reduction.
• Great early and final strength.

Pumping Aids – ADDAGE PUMPING AID

Pumping aids are a crucial element in enabling satisfactory flow of concrete with minimal problems through hoses and equipment. ADDAGE Pumping Aid significantly improves the cohesiveness of the mix blend and provides more resistance to segregation while pumping.

Benefits:

• Increased pumpability.
• Decreased wear and tear and friction on hoses.
• Reduced chances of blockages and pressure inconsistency.
• Provides more uniform placement.

Synthetic Fibers – PP Fiber

Polypropylene (PP) fibers are used in sprayed concrete for improved toughness and reduced cracking. These micro-reinforcements are effective in helping reduce the potential of shrinkage cracks and increases performance characteristics of the concrete.

Benefits:

• Decreased plastic shrinkage cracks.
• Increased impact and abrasion resistance.
• Increased ductility.
• Simple to disperse in the mix.

Micro Silica – Micro Silica Powder (Fumecrete 90)

Micro Silica, alternatively called Silica Fume, is the by-product of silicon mineral manufacturing at high temperatures. Fumecrete 90 is a high-purity verified micro silica powder that increases density and reduces permeability of sprayed concrete.

Benefits:

• Improved compressive strength and flexural strengths.
• Improved durability and chemical attack resistance.
• Decreased permeability and porosity.
• Increased bond to steel reinforcement.

Concrete Admixture – SNF-Powder

Sulfonated Naphthalene Formaldehyde (SNF) powder is a commonly used plasticizer in sprayed concrete applications. This high-performance chemical admixture greatly enhances the workability of the concrete mix, which will improve application and retrievability experience while spraying.

SNF also decreases the water-cement ratio of the concrete mix, creating a stronger end product and improved durability while lowering permeability.

The chemical admixture has a specific molecular structure that aids in the dispersion of cement particles, which leads to a uniform mixture and overall enhancement of the concrete performance and longevity. 

Benefits  

• Good water reduction properties. 
• Cost-effective solution for larger-scale projects. 
• Compatible with other admixture. 
• Increases early settings of strength gain. 

Conclusion

Sprayed concrete has transformed contemporary building methods by providing an efficient, fast, and flexible solution to a multitude of structural and aesthetic needs. Whether a tunnel, slope, swimming pool, etc., sprayed concrete offers flexibility to contractors and engineers.

As with all construction technologies, the incorporation of advanced admixtures and construction chemicals from respected brands, such as Sakshi Chem Sciences, is crucial to achieving desired performance characteristics.

PCE Powder, ADDAGE Pumping Aid, PP Fibers, Fumecrete 90, SNF Powder, etc., improve the application process and help improve durability and overall quality in usage on sprayed concrete.

As construction demands, sprayed concrete contributes to innovation, efficiency, and strength in building construction and general construction technology.