improvement in construction method

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Subject: Advance construction technology (3350605)
Topic: Grouting and Guniting
Prepared by Bhavesh Hathila

2. INDEX
1. GROUTING DEFINTION
2. CATEGORIES OF GROUT
3. PROPERTISE OF GROUT
4. SPECIFICTION FOR GROUT
5. TYPES OF GROTING MATERIUS AND THEIR
USE
6. APPLICTION OF GROUTING
7. TYPES OF GROUTS
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8. GROUTS WITH FILITERS
9. PROCEDURE OF GROUTING
10.GROUTING IN TUNNELS
11.SCHEMATIC PLAN GROUT
PLANT
12. GUNITING
13. SPRAYING OF CONCRETE
14. GUNITING

4. Grouting
• Grouting is the process of placing a material into cavities in
concrete or masonry structure for the purpose of increasing the
load bearing capacity of a structure, restoring the monolithic
nature of a structural member, filling voids around pre cast
connections steel base plates, providing fire stops, stopping
leakages, placing adhesives and soil stabilization.
• GROUT is a mixture of water, cement and optional material like
sand, water reducing admixtures, expansion agents and
pozzolans. The water to cement ratio is around 0.5. Fine sand is
used to avoid segregation.

5. Categories of grout
• Suspension Grout
• Liquid Grout or Solution Grout.
• Suspension grout is a mixture of one or several
inert materials like cement, clays etc suspended in
a fluid i.e water. Suspension grout is a mixture of
pure cement with water.
• Liquid grout or solution grout consists of
chemical products in a solution or an emulsion
form and their reagents. The most frequently used
products are sodium silicate and certain resins.

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7. Properties of grout
• Fluidity
• Minimum bleeding and segregation
• Low shrinkage
• Adequate strength after hardening
• No detrimental compounds
• Durable
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8. Specification for grout
• The sand should pass 150 µm IS sieve
• The compressive strength of 100 mm cubes of
the grout shall not be less than 17 N/mm² at 7
days
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9. Types of grouting materials and their
use
• Chemical grouting
- control seepage
- shut- off seepage
- soil stabilization
• Cementitious grouting
- mass placement
- structural(high strength)
- caustic environments

10. - high temperatures
 Epoxy grouting
- seal cracks
- bolt anchoring
- base plate levelling
- acidic environment
 Polyesters
- bolt anchoring
 Silicones
- smoke seals
- fire stops

11. Applications of grouting
Repairing of cracks
• The wide cracks may be repaired by filling
them with portland cement grout.
• The grout mixture may contain cement and
water or cement, sand and water, depending
upon the width of crack.
• The water cement ratio should be kept as low
as practicable to maximize strength and
minimize shrinkage.

12. Strengthening existing walls
• The lateral strength of buildings can be
improved by increasing the strength and
stiffness of the existing individual walls,
whether they are cracked or uncracked.

13. For soil stabilization
• Common methods are
- chemical grouting
- compaction grouting
- jet grouting

14. Types of Grouts
• Cement-based Grouts:
– Cement-based grouts are the most frequently used in
both water stopping and strengthening treatment. They
are characterized by their water cement ratio and their
Total Dry Matter / Water weight ratio. The properties
and characteristics of these grouts vary according to the
mix proportions used. However, they have the
following properties and characteristics in common.
• Stability and fluidity according to the dosage of the
various components and their quality
• Unconfined compressive strength linked to water
cement ratio

15. • Durability depending on the quantity and quality of
the components
• Easy preparation and availability
• Ease of use
• Relatively low cost mixes
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16. Pure cement grout
 It is an unstable grout. However, bleeding can be
avoided with water cement ratio less than 0.67.
 Usual mix proportions are from water cement ratio
0.4 to 1 for grouting. Very high mechanical strength
can be attained with this type of grout.
 During grouting, cement grains deposit in inter-
granular voids or fissures is analogous to a kind of
hydraulic filling.
 The grout usually undergoes a significant filtration
effect. The grain fineness is an important factor for
fine fissures.

17. Grouts with fillers
 Fillers are added in order to modify the viscosity of a
given grout so as to obtain a low cost product to substitute
the cement. The most commonly used fillers are the
natural sands and fly ash from thermal power stations.
 The term “mortar” is commonly used to specify grouts
with fillers that have a high sand content. Adding fillers
reduces the grout penetrability, as the fillers are of larger
grain sizes.
 Grouts with fillers are used when water absorption and/or
the size of voids are such that filling becomes essential
and when the leaking of grout into adjoining areas should
be limited.
 In addition, fillers in grout will produce low slump grout
with high viscosity for certain grouting purposes.

18. Procedure of grouting
• A 1:2 cement-sand grout with a water-cement
ratio between 0.6 and 0.8 is prepared using a
mechanical mixer.
• The mixture is then sent down under pressure
(of about 120kg/cm²) through a 30-50 mm
diameter pipe terminating into steel cages.
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19. • As the grouting proceeds the pipe is raised
gradually upto a height of not more than 60
cm above its starting level after which it is
withdrawn and placed into the next cage for
furthure grouting by the same procedure.
• After grouting the whole area for a height of
about 60 cm , the same operation is
repeated, if necessary , for the next layer of
60cm and so on.
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20. Grouting in tunnels

21.  Hose.
 Flexible hose is most commonly used for suction and
discharge lines. If the length of the discharge line is such
that pipe is necessary, a short length of hose should be
provided at the pump discharge and at the connection to
the grout header.
 Piping.
 Black steel pipe and fittings 1-1/2 in. in diameter are
normally suitable for pressure lines ; but where large
quantities of grout are to be injected and the supply line is
long, it may be desirable to provide a larger size pipe and
connection hoses.
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22.  Grout Header.
The grout header is usually assembled as a unit in
order—that it may be moved from one grout hole to
another. The assembly consists of the operating
valves, a pressure gage, pipe, and the necessary
fittings to attach the header to the hole and to attach
the grout supply and return lines.
 Pressure Gages.
Reliable pressure gages are essential in pressure
grouting. They constitute the principal index to the
behavior of the hole and the stresses that are being
produced in treated material.
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23. Schematic Plan of Grout Plant
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24. Guniting
• Guniting is an effective technique, which
has been extensively used in the
rehabilitation of structurally distressed R.C
members. There has been case of heavy
rusting of the mesh in the form of powder
or in the form of a sheet coming out.
Distressing before restoration is possible
only in case of overheads tanks which can
be restored when the tanks are empty.

25.  Gunite is also known as shotcrete or
pneumatically applied mortar
 It can be used on vertical and overhead, as well
as on horizontal surfaces and is particularly
useful for restoring surfaces spalled due to
corrosion of reinforcement
 Gunite is a mixture of Portland cement, sand
and water, shot into the place by compressed air

26.  Sand and cement are mixed dry in a mixing
chamber, and the dry mixture is then transferred
by air pressure along a pipe or hose to a nozzle,
where it is forcibly projected on to the surface to
be coated
 Water is added to the mixture by passing it
through a spray injected at the nozzle
 The flow of water at the nozzle can be controlled
to give a mix of desired stiffness, which will
adhere to the surface against which it is
projected

27. • A cement-sand mix, in the ratio 1:2 or 1:3
depending upon the requirement, is applied
at high pressure over the surface with the
help of specialized equipment.
• Guniting is extensively used to rehabilitate
concrete bridges, dams, spillways,
buildings, marine structures, etc.

28. Spraying of concrete
 There are two different methods of spraying:
– Dry process spraying
– Wet process spraying
 Dry process spraying is the process in which the
mixture of damp sand and cement is passed through
the delivery hose to the nozzle and the water is
mixed at that time.
 Water cement ratio should be between 0.33 and 0.50
 This process is often used for repair work.
 It is because of its fast application process and
restoration of structural strength at an early stage.

29. • The performance characteristics of dry
sprayed concrete are they have good density
and high strength.
• It has very good bond to a suitable
substrate.
• These advantages make it more variable
than conventional concrete and wet process
sprayed concrete.

30. Guniting

31. Thank you