Shotcrete or sprayed concrete (Gunite®) is concrete or mortar conveyed through a hose and pneumatically projected at high velocity onto a surface, as a construction technique. It is typically reinforced by conventional steel rods, steel mesh, or fibers. Shotcrete is usually an all-inclusive term for both the wet-mix and dry-mix versions. In pool construction, however, shotcrete refers to wet mix and gunite to dry mix. In this context, these terms are not interchangeable. Shotcrete is placed and compacted at the same time, due to the force with the nozzle. It can be sprayed onto any type or shape of surface, including vertical or overhead areas.

1. Presented by;
N.OBUL REDDY
14L41A0105
MEKAPATY RAJAMOHAN REDDY
INSTITUTE OF TECHNOLOGY AND
SCIENCE

2. CONTENTS
 INTRODUCTION
History
DEFINITION OF SHOTCRETE
 SHOTCRETE MATERIALS
EQUIPMENTS USED IN SHOTCRETE
SHOTCRETE VERSUS CONVENTIONAL CONCRETE
DRY PROCESSES
WET PROCESS
 APPLICATIONS OF SHOTCRETE
 ADVANTAGES
 DISADVANTAGES
CONCLUSION
 REFRENCES

3. INTRODUCTION
•Shortcreting has proved to be the best method for construction
of curved surfaces.
•Domes are now much easier to construct with the advent of
with this shotcrete technology.
•Tunnel linings are also becoming easy technology.
•It also enumerates the different types of process involved in
shotcreting.

4. HISTORY
 Shotcrete was invented in the early 1900s by American
taxidermist Carl Akeley.
used to fill plaster models of animals.
In 1911, he was granted a patent.
Until the 1950’s, the wet-mix process was devised, only
the dry-mix process was used.

5. DEFINITION OF SHOTCRETE
•Shotcrete is a mortar or high performance concrete conveyed
through a hose and pneumatically projected at high velocity onto a
receiving surface.
• The applied mixture of cement, aggregate, and water conveyed
through a hose and projected at high velocity onto the application
surface.

6. SHOTCRETE MATERIALS
 Portland Cement
 Water
 Sand
 Aggregate
 Admixtures / Fibers

7. EQUIPMENTS USED IN SHOTCRETE
 Batching and mixing equipment
Admixture dispensers
 Air compressor
Nozzles
Shotcrete accelerator

8. SHOTCRETE VS CONVENTIONAL CONCRRETE
conventional concrete is first placed and then compacted in the
second operation.
shotcrete undergoes placement and compaction at the same time.
Shotcrete is more dense, homogeneous, strong, and waterproof.
It can be impacted onto any type or shape of surface, including
vertical or overhead areas.

9. Dry process
Step1: Pre blended, dry or semi-dampened materials are placed
into shotcrete equipment and metered into a hose.
Step2: Compressed air conveys materials at high velocity to the
nozzle where the water is added.
Step3: Then the material is consolidated on receiving surface by
high impact velocity.

10. 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.

11. Wet process
Step1: All ingredients, including water, are thoroughly mixed and
introduced into the shotcrete equipment.
Step 2: Wet material is pumped to the nozzle where compressed air
is introduced.
Step 3: Mostly wet-process shotcreting is done with premixed
mortar or small aggregate concrete.

12. 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.

13. APPLICATION OF SHOTCRETE
Support of underground openings in tunnel, mines, drainages
and bridges.
•Piers / Docks
•Ditches
•Retaining Walls

14. Rehabilitation of subway tunnels construction of domed roofs.
Highway culvert repair
and arch culvert

15. ADVANTAGES:
• Little or no framework is required.
• Cost effective method for placing concrete.
• Ideal for irregular surfaces application.
• Allows for easier material handling in areas with difficult access.
• Easy start up, shutdown and clean up.
• Increase in load bearing capacity due to redistribution of stresses.
• Excellent corrosion resistance.

16. DISADVANTAGES
•Rain may wash out the cement leaving a sandy surface, or it may
saturate the shotcrete and cause sloughing or sagging.
• Strong wind will separate the material between the nozzle and the
point of deposit, reducing the strength.
• It requires skilled and experienced labours.
• A greater degree of geotechnical knowledge is required.
•Improperly applied shotcrete may create conditions much worse
than the untreated condition.

17. CONCLUSION
•The use of Shotcrete to build new concrete structures as well as
to restore and repair existing structures is well known and
documented and it is perhaps the most diverse method available
for concrete construction.
•The use of this innovative technology is increasing day by day
and procedures for its proper performance are well developed
and high quality work is regularly obtained.
•Shotcrete is a viable option for doing superstructure
repair(unformed) and substructure repair (unformed) if done
strictly according to specifications and best practices.
•It is a good substitute for the manual lay-up method for vertical
and overhead applications using rapid set mortar.

18. REFRENCES
www.powershow.com/.../Scaling_and_Bolting_or_Shotcrete
Powerpoint
www.slideshare.net/MTarunkumarreddy/shotcrete
https://www.google.co.in
www.scribd.com/Concepts-of-Shot-Crete-Technology.