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Shotcrete is an all-inclusive term for spraying concrete or mortar with either a dry or wet mix process. However, shotcrete may also sometimes be used to distinguish wet-mix from the dry-mix method. The term shotcrete was first defined by the American Railway Engineers Association (AREA) in the early 1930s. [6]
The primary advantages of fibre-reinforced shotcrete are: Addition of steel fibers into the concrete improves the crack resistance (or ductility) capacity of the concrete. Traditional rebars are generally used to improve the tensile strength of the concrete in a particular direction, whereas steel fibers are useful for multidirectional ...
The volumetric mixer varies in capacity size up to 12 m 3 and has a production rate of around 60m 3 an hour depending on the mix design. Many volumetric concrete mixer manufacturers have innovated the mixer in capacity and design, as well as added features including color, multiple admixes, fiber systems, and the ability to do gunite or shotcrete.
The new Austrian tunneling method (NATM), also known as the sequential excavation method (SEM) or sprayed concrete lining method [1] (SCL), is a method of modern tunnel design and construction employing sophisticated monitoring to optimize various wall reinforcement techniques based on the type of rock encountered as tunneling progresses.
Design mix ratios are decided by an engineer after analyzing the properties of the specific ingredients being used. Instead of using a 'nominal mix' of 1 part cement, 2 parts sand, and 4 parts aggregate, a civil engineer will custom-design a concrete mix to exactly meet the requirements of the site and conditions, setting material ratios and ...
Headframes may be either steel or concrete and their design will determine how they are constructed. The Galloway is moved in the shaft by means of winches, which move slowly and are rated for significant loads, while the sinking buckets (or kibbles) are moved in the shaft by the sinking hoist, which moves quickly and is rated for less load ...
Shotcrete is also used for applications where seepage is an issue to limit the amount of water entering a construction site due to a high water table or other subterranean sources. This type of concrete is often used as a quick fix for weathering for loose soil types in construction zones. There are two application methods for shotcrete.
Drilling of the tunnel face anchors, Val di Sambro Tunnel, Italy. The Analysis of Controlled Deformation in Rocks and Soils, translated from Italian Analisi delle Deformazioni Controllate nelle Rocce e nei Suoli (ADECO-RS), also known as The New Italian Tunneling Method (NITM), [1] is a modern tunnel design and construction approach.