Shotcrete, or sprayed concrete, was first used in 1907 and involves pneumatically projecting a concrete or mortar mixture at high velocity onto a surface. There are two main processes - dry process involves adding water at the nozzle, while wet process fully mixes all ingredients beforehand. Shotcrete provides advantages for constructing curved surfaces like domes and tunnels efficiently due to its ability to be sprayed onto irregular surfaces with little formwork needed. It allows for material placement in hard to access areas.

2. INTRODUCTION: -
 Shotcrete is the sprayed concrete, which was first
used in Pennsylvania, USA in 1907 by Dr.Aneley.
 Shortcreting has proved to be the best method for
construction of curved surfaces like
Domes,Tunnels etc.,
 The technology is improving giving us enhanced
comforts and the task is completed with a greater
economy in terms of both time and investment.

3. DEFINITION OF SHOTCRETE:-
 Shotcrete is a mortar or high performance
concrete conveyed through a hose and
pneumatically projected at high velocity onto a
backing surface.
 Usually patented polypropylene fibers are
included in the shotcrete which increases the
cohesive nature of the shotcrete through
mechanically binding the cementitious materials
together.

5. Dry process:
1.Pre blended,
dry or semi-
dampened
materials are
placed into
shotcrete
equipment and
metered into a
hose.
2. Compressed
air conveys
materials at high
velocity to the
nozzle where the
water is added.
3. Then the
material is
consolidated on
receiving surface
by high impact

6. ADVANTAGES OF DRY PROCESS:-
 Easy start up, shutdown and clean up.
 Control of materials is on site.
 Nozzle man can be up to 1000ft horizontally or
500ft vertically from the gun.

7. WETPROCESS:
1.All ingredients,
including water,
are thoroughly
mixed and
introduced into
the shotcrete
equipment.
2. Wet material is
pumped to the
nozzle where
compressed air is
introduced to
provide high
velocity
3. Mostly wet-
process
shotcreting is
done with
premixed mortar
or small
aggregate
concrete.

8. ADVANTAGES OF WET PROCESS:-
 Little or no formwork is required.
 Cost effective method for placing concrete.
 Ideal for irregular surface applications.
 Allows for easier material handling in areas with
difficult access

10. 1.Tunnel lining is made much easy by this process.
2. Shotcrete technology proved to be more efficient and easy for the construction
of domed roofs.
Tunnels domes