Wonderland and its use of Shotcrete and Concrete
When people mention shotcrete, most will be met with confused looks. Shotcrete is concrete but applied in a very different way from conventional concrete. When most people think of concrete, they imagine wooden forms and concrete pouring. There are other ways of applying concrete. Anyone who has been to Canada’s Wonderland has unknowingly come in contact with shotcrete.
Shotcrete was first invented by Carl E. Akeley on June 24, 1907, and was applied using a very rudimentary machine, called a “plaster gun” . The development from plaster to concrete took only a couple of years, and by 1911 the cement gun was patented. The name “shotcrete” itself comes from “shot” and “concrete” put together, since the concrete is literally shot out of a spray nozzle.
From Akeley’s time, shotcrete has advanced and developed as technology progressed. Today there are different ways of applying shotcrete. Some guns use premixed concrete fed into the hose and sprayed on. Others use dry aggregate and cement fed in the hose and mixed with water right before it exits the nozzle. This second method is specifically called Gunite, which is trademarked. Gunite quality depends on the skill of the concrete worker, also known as a “nozzle-man”. The “nozzle-man’s” skill and experience are critical since he is the one who controls the water-to-dry-mix ratio. He controls how much water is added to the mix as it sprays out of the nozzle. The density of the concrete and its compression strength greatly depend on the ratio of water to dry-mix. This makes it a bit riskier to use than traditional concrete pouring, which is more uniform since it is mixed at a concrete plant with computer-controlled ingredients.
Shotcrete has specific applications where it exceeds traditional concrete forming. Shotcrete concrete under high pressure is shot out of the hose and sticks to where it was shot due to the impact force. This stick-on contact method allows it to create complex forms easier than traditional concrete. Shotcrete was used in Canada’s Wonderland for the repair of the famous Wonder Mountain. Besides, it was used to create structures for the famous Halloween Haunt, such as large serpents, trees and skeletons. The reason for using shotcrete is because it can make rounded objects and circular details easier than traditional concrete. At wonderland, Wonder Mountain has few straight walls but instead features curves that mimic natural contours. Shotcrete is also used in concrete pool construction, since, again, it can make a circular pool easier than concrete forming. Concrete forming is faster to pour, though, when dealing with regular square or rectangular pools.