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2015FallShotcreteEMag

Wet-Mix Shotcrete— with the Flexibility of Dry Mix By Walter Betschart H flexible way and with less cleanup?” There pressed air in the hoses and pipes will do the-cations. As concrete is blown to the nozzle,simply let the hopper go empty and the comave you ever thought to yourself, “Is therea way to shoot wet-mix shotcrete in a more is one. rest. There is no concrete loss when stopping Wet-mix shotcrete, as per common knowledge, the machine. The machine itself can quickly requires rather large pumps with pistons or be washed down with a hose. No high-pressure worms. Concrete is mechanically pushed to the water jet is needed. nozzle as a dense stream. At the nozzle, air and • As mentioned before, Aliva rotor machines accelerator (if required) are added to project and offer a great range of output capacity. A well- compact the material to the substrate. chosen machine type and size and its acces- Worm pump machines can deliver concrete sories will enable you to do anything from with maximum aggregate sizes of 0.15 in. (4 mm) small concrete repairs up to slope or tunnel and are typically used for repair and surface fin- stabilization with the same equipment. This ishing projects. The output is typically up to comes in handy in confined and narrow areas 5 yd3/h (4 m3/h). such as wastewater and water tunnels. Double-piston pump-based machines also • Midsize rotor pumps with capacities from 1 to supply a dense stream of concrete to the nozzle 13 yd3/h (0.75 to 10 m3/h) are very compact and can be virtually pulse-free when shooting. and fit on the bed of almost any truck. With This type of machine can produce high outputs weights between 1400 and 2600 lb (640 and from 5 to 33 yd3/h (4 to 25 m3/h), being particu- 1200 kg), these machines are easier to handle larly suitable for large tunnel construction or than large piston pumps. where substantial structural volumes are required. • Small and midsize rotor chamber pumps are A third possibility, not well known in North also available with an air-driven motor. This America, is wet-mix shotcreting with rotor eliminates the need for electricity and offers a machines. Rotor chamber pumps of Aliva®, good solution at places such as carbon mines, which are commonly known for their use with where no sparks are wanted. the dry process, have been further developed • Steel and synthetic fibers can also be processed, over the years to also shoot wet-mix concrete. as well as aggregate up to 0.5 in. (13 mm) They are being successfully used for wet shot- with a small rotor and 0.75 in. (19 mm) with crete application in mining and civil construction a big rotor. throughout Europe, as well as many other parts • If needed, there will always be the possibility of the world. to change from wet to dry concrete without Aliva rotor machines, basically the same as making any changes on the machine. Merely in the dry process with the help of compressed replacing a small piece at the gun gives you air, blows wet concrete from the pump to the that flexibility at a very low cost. nozzle where the accelerator (if necessary) can Aliva rotor concrete spraying machines are be injected. The capacity of this type of equip- perfectly compatible with mechanical manipula- ment ranges between 0.90 to 25 yd3/h (0.7 to tors such as AL-302.1 telescopic spraying arms 19 m3/h), depending on the size of the equipment or AL-101 Quick Connect spraying heads that can and the volume of the rotor installed. They are be attached to a wide range of excavators or capable of delivering concrete to the substrate backhoe loaders of any brand. With the help of at a regular rate and almost free from pulsation. manipulators, you will be able to reach a high Shooting wet-mix concrete with rotor pumps output and thus fully take advantage of the poten- does have advantages that simply cannot be tial of Aliva rotor pumps. dismissed: Hoses for shotcrete with rotor pumps are gen- • Whenever you have a job where you know erally much easier to handle. As the concrete is there will be many stops and interruptions, blown through the hose instead of being pumped, with a rotor machine there will be no compli- this eliminates the heavy concrete mass in the 26 Shotcrete • Fall 2015


2015FallShotcreteEMag
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