Grouting

Grouting is the process of injecting materials into cavities or cracks in concrete, masonry structures, rock-mass, subsurface soil, or rock to increase the structure’s load-bearing capacity, and the material used for this objective is called grout.

It is the specifically prepared cement under pressure to form a stable suspension or liquid into pores, fissures or voids, or cement mixtures at a high flow rate to increase strength.

While grout is normally a combination of cement, sand, and water or chemical substances which can be used to fill gaps.

They are used to improve concrete cracks, gaps in tiles for sealing & waterproofing for soil stabilization, it is also used to provide the extra strength to the foundations of load-bearing structures.

Characteristics of Grouting:

• Grouting is non-corrosive.
• They are not flammable, non-toxic.
• Also, they are shrinkage compensated.
• They are capable of adjustable fixtures.
• They have very good flow characteristics.
• It has an excellent bond to concrete.
• In addition, they have no blockage or bleeding.
• They are easy to use, easy to mix only add water.
• They are impact and vibration resistant.

Types of grouting materials:

1.Un-sanded Grouting:

It is used for wall tiles where the grout joint is lower than 1/8” wide.

2.Finely Sanded Grouting:

It is used for flooring tiles, where the joints are 1/8” to 3/8” wide.

3.Quarry Type Grouting:

This is much like finely sanded grout for ceramic tiles besides {that a} coarse grade of sand is used.

Quarry-type grout is used for joints which can be 3/8 “to 1/2” wide used with Saltillo tiles.

4.Epoxy Grouting:

It contains an epoxy resin and hardener.

Epoxy grout for ceramic tile is very resistant to stains and chemicals, it has amazing bond energy.

It is best for countertops and different areas inclined to stains.

5.Cementations grouting:

It is used for mass placement in caustic environments.

6.Chemical grouting:

It is used to control seepage, shut-off seepage, and soil stabilization, it is further classified as follows:

A. Permeation Grouting:

Permeation grouting is a means to preventing voids within the mass of soil or rock, thus displaces water and air from the voids.

Allows it to grow without displacing the sod particles or widening the existing fissure in the grout.

B. Displacement-Compaction Grouting:

Compaction grouting is the injection of a thick or mobility grout that does not reside in any homogeneous mass without entering the pores of the soil.

As the grout mass expands, the surrounding soil displaces and wanders.

When low-slump condensation grout is injected into granular sods, grout bulbs are formed that displace and condense the surrounding loose soil.

It is used to repair structures that have excessive disposal.

C. Displacement-Soil Fracture Grouting:

Soil fracture is a displacement grouting method in which a solution of cement clay and water is injected into the soil to freeze the excessive pressure to form root-like or skinny lens-shaped zone materials within the soil mass.

The grout materials are unfolded across the grout gap which will increase the density of soil mass and its macroscopic strength.

D. Jet or Replacement-Displacement Grouting:

In this technique, a special grout pipe called a monitor that has high-speed jets of water or grout is used to erase and dig the soil.

Then the monitor is retracted, sturdy impervious columns are formed by mixing the grout with the remaining soil.

E.  Rock Fissure Grouting:

Rock fissure grouting is the used for a gap drilled by the fissures and joints of a rock mass, permitting the grout to be injected into close centres vertically and re-injected if needed.

There is just one grouting mechanism for rock grating, the grout is injected under pressure through a grout gap drilled into the rock mass for treatment.

F. Tube-a-Machetes (TAM) Grouting:

Tube-a-Matches (TAM) grouting is the use of sleeve perforated pipes in grout holes, soils, or completely decomposed rock, the grout will be injected into shut centers and re-injected if needed.

Mixture of Grouting:

For flowable water: Powder 0.14 to 0.16 by weight (4.2 L to 4.8 litres of water per 30 kg bag).

For Pore able water: Powder: 0.12 to 0.14 by weight (3.6 L to 4.2 litres of water per 30 kg bag).

Mixing Time: Minimal three minutes.

Mixing Instruments: 

• Mix the grout powder with the specific ratio within the water of a low velocity (maximum 500 rpm) electric drill so as not to put an excessive amount of air.
• Pour about 80 to 90% of the required water into the mixing drum after which add the balance water.
• Depending on the specified stability and movement properties, the blending ratio will be adjusted.

Advantages of Grouting:

1. This may be achieved on virtually any floor situation.
2. It does not induce vibration and it may be controlled to avoid structural damage.
3. Improvements in ground structures can be measured.
4. It is very useful for limited space and low headroom applications.
5. The slab is used for jacking that elevates or flattens the deformed foundation.
6. It can be installed adjacent to existing walls.
7. It can be used to control the seepage, groundwater flow and hazardous waste materials.

Disadvantages of Grouting:

1. Generally, large lateral soil stresses may be seen during the removal of lateral supports and cracking of the ground surface.
2. The tendency of the high ground lost due to drilling techniques, especially on certain granular soils.
3. It is less suitable for coarse-grained soils and softer soils which have shorter self-support times and the risk of soil creep.
4. Only suitable for digging above groundwater.

Applications of Grouting:

• Construction of large-scale concrete structures and piles.
• Fixing of ground anchors for sheet pile walls, concrete pile walls, retaining wall tunnels, etc.
• A formation or cracks and repair of the ground beneath the structural.
• Defects the faults on the construction of masonry or pavement.
• Fixing of tendons in prestressed concrete or post-tension concrete.
• In tunnel works filling the void between the lining and the rock face.

Also read: Dewatering, Caisson Disease & Pointing

Conclusion:

This technique for grouting in soil formation with the partial or complete displacement of groundwater, for every grouting mechanism, a short discussion on its design idea and utility is done.