Repair techniques : Grouting, Various method for grouting , compaction grouting, permeation grouting , fracture grouting

1. DEPARTMENT OF
CIVIL ENGINEERING
Repair Techniques:
Grouting
Er. Ramprasad Kumawat
M.Tech

2. • Repair Techniques: Grouting, Jacketing,
External bonded plates processes,
limitations, design computations etc. including
numerical problems.
• Under Water Repair: Processes

3. GROUTING
• Grouting is a process of filling the cracks or voids
under pressure in concrete or masonry structural
member to change its physical characteristics.
• Grout is a flow able plastic material with
negligible shrinkage to fill the voids completely.
• In this technique Grouting machine, mixture
(cement, sand, water) are used to fill the cracks
and voids in the structure.
• Grouting is suitable where soil permeability
creates a very heavy demand on pumping .

4. Various methods for Grouting
• 1) Compaction Grouting
• 2) Permeation Grouting
• 3) Fracture Grouting

5. 1. Compaction Grouting
• Compaction Grouting is also known as Low
Mobility Grouting.
• Compaction Grouting involves injection of low
mobility grout with the help of drill casings that
are drilled or driven to pre-set depths.
• The grout, usually consists of cement, sand, fly
ash and water, is placed from the bottom-up with
pressure-based criteria .
• After each consecutive stage, the drill casing is
lifted upwards to the point till it is entirely taken
out.

6. 2. Permeation Grouting
• Permeation grouting which is also known as
penetration grouting.
• It is the most common and conventional grouting
method to repair the deteriorated structure.
• It involves filling of any cracks, joints or voids in
rock, concrete, soil and other porous materials.
• The objective is to avoid without displacing the
formation or creating any change in volume or
configuration in the medium.
• This is typically useful to strengthen the existing
formation, creating an impermeable water barrier
or both.

7. 3. Fracture Grouting
• Fracture grouting also known as compensation
grouting.
• In Fracture grouting, a low viscosity grout that
splits through the ground by hydraulic fracturing
is used which penetrates into the fractures.
• The in-situ soils are displaced and soil
immediately next to the fractures are densified,
but to a lesser extent as compare to the
compaction grouting.

8. Grouting Procedure for Repair of
Cracks in Concrete Structures
1.Holes are drilled in structure along cracks
and in an around hollow spots.
2.If there are several cracks, holes can be
drilled in a staggered manner at 500 to 750
mm spacing in both directions covering
adequately the area proposed to be grouted.
Holes spacing can be altered as per site
conditions.

9. 3.G.I. pieces (12 to 20mm dia x 200mm) wi
th one end threaded or PVC nozzles are
fixed in the holes with rich cement mortar.
4.All the cracks and annular space around
G.I. pipes are sealed with
rich cement mortar.
5.All the cracks are cut open to a ‘V’
shaped groove, cleaned & sealed with rich
cement mortar

10. • All holes are first plugged with proper wooden
plugs or locked in the case of PVC nozzles.
• The bottom most plug and the two adjacent
plugs are removed and water injected in
the bottom most hole under pressure.
• When the clear water comes out through
the adjacent holes the injection of water is
stopped and the plugs in the
bottom most hole and the one immediately
above are restored.

11. • The process of grouting of concrete cracks
is repeated with other holes till all the
holes are covered .
On the day of grouting all the plugs are
removed to drain out excess water and
restored before commencing grouting
The same sequence as described above is
adopted for injecting the cement grout also.
The grout is kept fully stirred/ agitated under
pressure throughout the grouting.

12. • The grouting is carried out till refusal and /
or till grout starts flowing from the adjace
nt hole. A proper record of the quantity of
grout injected into every hole should be
maintained.
• After grouting, curing should be done for14
days. Tell tales are provided for checking the
effectiveness of grouting.
• Only such quantities of material for preparing
grout should be used, as can be used within 15
minutes of its mixing. Grouting equipment
must be cleaned thoroughly after use.

13. Fig: Grouting Procedure for Concrete Cracks Repair

14. Precautions during Grouting of Cracks in
Concrete
• During the grouting operation in track or
close to it, speed restrictions of stop-dead and
proceed at 10 kmph shall be imposed at the
site of work and same should be continued for a
period of 24 hours.
• The restriction may then be relaxed to non-
stop 30 kmph to be continued for a period
of another 2-3 days. However, speed
restrictions indicated above are only guidelines
and appropriate speed restriction at each
individual site should be considered.

15. • Immediately after grouting work, all the
grouting equipment including the slurry and
mixing drums, pipes, nozzles, etc.
• should be thoroughly washed so that set
cement does not damage the equipment.
• After the work has been completed, it sho
uld be inspected thoroughly and should be
kept under observation for a period of
6 months to 12 months for its behavior
after grouting.

16. Types of Injection Grouting and Materials for
Concrete Crack Repair
• Following are the various types of injection
grouting and materials for concrete crack
repair:
• Polymer injection grouting
• Fiber-reinforced injection grouting
• Cement – sand grouting
• Gas-forming grouting
• Sulfo-aluminate grouting

17. 1. Polymer Injection Grouts
• Polymer injection grouting is based on use of
polymers such as polyester, epoxy, vinyl ester,
polyurethane and acrylic resins.
• The most popular polymer used for epoxy
grout is epoxy. Polyurethane and acrylic resin
based polymers are used for treatment of water
retaining structure, underground structures as
well as to prevent seepage of water.

18. • The polymer injection grouts are available in
three component materials and two component
materials.
• The three component materials grout includes:
• (i) Liquid resin content
• (ii) Curing agent or hardener
• (iii) Aggregate or dry filler

19. • The two component materials grouts
include:
• (i) Curing agent or hardener
• (ii) Aggregate or dry fillers.

20. Following are properties of different types of
Polymer Based Injection Grouting
• Epoxy based injection grouts possess low pot
life, non-resistant to ultraviolet exposure and
high temperatures, non-shrink, flow able,
effective in sealing cracks, excellent bonding
with almost all building materials, good
chemical resistance.

21. Acrylic polymer based injection
Grouts possess improved flexural and tensile
properties, resistance to cracking, segregation,
improved impermeability, chemical resistance,
rapid setting. Shrinkage may reduce/increase
resistance to corrosion of Steel, Dynamic
load/vibrations resistant.

22. 2. Fiber-Reinforced Injection Grouts
• Fiber reinforced concrete is used for repair of
concrete and masonry structural members.
• Fibers such as polypropylene, Steel or Glass
fibers are used with Portland cement or
shrinkage compensating mortar to repair and
strengthening of structural members to provide
improved flexural strength, impact resistance
and ductility.
• Fiber reinforced injection grouts require
skilled handling to avoid segregation of fibers.

23. 3. Cement – Sand Grouts
• Cement-sand grout is the most popular type of
grout used for repair of concrete or masonry
structure and is easily available.
• This grout is used for the places where
strength enhancement of structure is not
required.
• This is also most popular because it is readily
available in the market and is cheapest form of
repair of concrete and masonry structural
members.

24. • This method requires high water and cement
contents for injection purpose.
• The use of cement-sand grouts results in
shrinkage and cracking of grout at hardening
and to minimize this, suitable shrinkage
compensating agents are required.
• Use of cement-sand grouts is very common in
masonry buildings, but not very common in
concrete.

25. 4. Gas-forming Grouts
• The gas-forming injection grout is used based
on the principle that the gas bubbles expand
the grout to compensate shrinkage of grout
after application.
• These gas bubbles are generated on reaction of
some ingredients (usually Aluminium and
Carbon powder contained in grout) with the
cement liquor.

26. • The gas bubble forming injection grouts are
temperature sensitive and is not suitable for
high temperature application require proper
confinement to develop strength and volume
stability, as the reaction forming gas bubbles
may be too fast and may complete before
placing of the grout.

27. 5. Sulfo-aluminate Grouts
• Sulfo-alum injection grout is also based on the
principle shrinkage compensation.
• In these grouts either shrinkage-compensating
cement or anhydrous sulfo-aluminate
expansive additive is used with Portland
cement.
• The additive results, in expansion at hydration.

28. • This produces expansion after the grout has set
and is more reliable than gas -forming grouts.
But the expansion of such grouts requires post-
hardening curing and it will not be effective if
moist curing is not available.

29. • THANKS!
• Gmail: ramkumawat001@gmail.com