Jamar Adams Nina Brabham Anas Ghandorah Dan 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 yd 3 /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 MixDry 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

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