is “mortar conveyed through a hose and pneumatically
projected at High velocity on to a surface” *-ACI
it different from conventional concrete?
conventional concrete, which is first placed and then compacted
(vibrated) in a second operation, gunnite undergoes placement
and compaction at the same time due to the force with which
it is projected from the nozzle. Because of this it is more
dense, homogeneous, strong and waterproof than any other process.
is not placed in forms, it can be impacted onto any type of
shape Of surface, including vertical or overhead.
How Gunnite works
1. Adhesion or Bond
The bond with properly cleaned concrete, brick or stone actually
is Stronger than the material to which it is applied.
The force of application by compressed air and the “peening”
effect of The larger particles result in a very dense and
impervious mass with an Absolute minimum of entrained air.
Extreme strength, hardness and abrasion resistance of the
material are Attributable to two factors . . . the method
of placement and the addition Of only the proper amount of
water. Ultimate compressive strength has Been tested at 6000
psi or greater in 28 days.
Resistance to Absorption or Percolation
The density and watertight qualities of dry-process Shotcrete
will allow It to withstand conditions which ordinarily destroy
or damage concrete. It has been successfully used for structures
subjected to alkalies, acids, Salt water and certain corrosive
Low Water-Cement Ratio
The excellent physical properties of the material are due
to the water Content being only the amount needed to satisfy
chemical hydration (averaging 3 to 3 ½ gallons per
bag of cement). In addition, placement at high velocity against
a surface instead of forms results in the rejection of excess
material or “rebound”.
Expansion characteristics of dry-process Shotcrete are almost
identical to Low-carbon steel. The expansion allows for flexibility
of the steel-reinforced Mass and also minimizes cracking.
Underwriters' Laboratories, after conducting extensive tests
on slabs, gave Dry-process Shotcrete extraordinary allowances
for reinforced construction.
Dry-process Shotcrete can be placed against surfaces without
forms and will Conform to any irregularities in the surface.
Thicknesses can be from a Fraction of an inch to 10-12 inches
and repair– bridges, foundations, walls, parking
garages, canals, Silos
construction – buildings, pools, tanks, domes
Proofing – foundations, walls, parking garages,
bulk storage silos
– slopes, seawalls, piers
protection – supports, piping
– zoos, theme parks, churches, special environments
– sealing, stabilizing
– primary support, finished linings
How Gunnite works