SHOTCRETE

Jamar AdamsNina BrabhamAnas GhandorahDan Holombo

Materials

Portland cement, lightweight aggregate, and admixtures

The same type of reinforcing is used in shotcrete as in conventional concrete, like rebar, prestressed steel, and wire mesh.

Additives Silica Fume- reduced permeability,

increased compressive and flexural strength

Air-Entraining Admixtures- improved pumpability and freeze-thaw durability

Fibers- control cracking, improve impact resistance and energy absorption

Accelerators- improve placement characteristics in adverse conditions and increase production capabilities

Properties

Hardened properties similar to conventional cast-in-place concrete

Shotcrete normally has a greater compressive strength then cast in place concrete due to lower water to cement ratio

Placement Uses compressive

air to spray the concrete at high velocities

Can be placed on soil, existing concrete, block or brick, and prefabricated forms

Wet Mix- all constituents, water included, are thoroughly mixed before placement

Dry Mix (Gunite)- water is added to dry materials during placement

Tools and Machines Concrete output: 50

yd3/hr Concrete pressure:

1361 psi Horizontal pumping

distance: 1200 ft Vertical pumping

distance: 450 ft Max aggregate size:

1.5 in

Tools and Machines

2 ½ in. spray nozzle 2 in. spray nozzle

Wet Mix Dry Mix (Gunite)

Applications Homes and

buildings Tunnels Channels Dams Retaining walls Bridge retrofits Recreation (pools,

zoos, skateparks, waterparks)

Benefits

Lowers cost due to quick speed of construction

Easier to construct complex forms or shapes

Can use recycled materials such as fly ash and rebar in the mix

Bonds well with most surfaces No forming needed, therefore lower

costs

References

http://www.cement.org http://www.wseshotcrete.com http://www.advancedshotcrete.com http://www.gunite.us http://www.reedpumps.com http://www.earthshelter.com http://www.wsdot.wa.gov http://www.shotcretetechnologies.com