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Other manufacturers were thus compelled to use other terminology to describe the process such as shotcrete, pneumatic concrete, guncrete, etc. 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.
Traditional rebars are generally used to improve the tensile strength of the concrete in a particular direction, whereas steel fibers are useful for multidirectional reinforcement. This is one of the reasons why steel fiber reinforced (shotcrete form) concrete successfully replaced weldmesh in lining tunnels. Less labour is required.
Some of the important characteristics of materials are : strength, durability, flexibility, weight, resistance to heat and corrosion, ability to cast, welded or hardened, machinability, electrical conductivity, etc. [3] In contemporary design, sustainability is a key consideration in material selection. [4]
The compressive strength of a concrete is determined by taking standard molded, standard-cured cylinder samples. Many factors need to be taken into account, from the cost of the various additives and aggregates, to the trade offs between the "slump" for easy mixing and placement and ultimate performance.
Twenty eight days is a long wait to determine if desired strengths are going to be obtained, so three-day and seven-day strengths can be useful to predict the ultimate 28-day compressive strength of the concrete. A 25% strength gain between 7 and 28 days is often observed with 100% OPC (ordinary Portland cement) mixtures, and between 25% and 40 ...
The test hammer hits the concrete at a defined energy. Its rebound is dependent on the hardness of the concrete and is measured by the test equipment. By reference to a conversion chart, the rebound value can be used to determine the concrete's compressive strength. When conducting the test, the hammer should be held at right angles to the ...
Shotcrete#Shotcrete vs. gunite, concrete or mortar conveyed through a hose Gunite (horse) , an American Thoroughbred race horse Topics referred to by the same term
Flow table with a grip and a hinge, 70 centimetres (28 in) square. In the American version of this test, the table is 10 inches (25 cm) diameter per ASTM C 230.; Abrams cone, open at the top and at the bottom - 30 centimetres (12 in) high, 17 centimetres (6.7 in) top diameter, 25 centimetres (9.8 in) base diameter.