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Shotcrete definitions and terminology
Published in Dudley Robert (‘Rusty’) Morgan, Marc Jolin, Shotcrete, 2022
Dudley Robert (‘Rusty’) Morgan, Marc Jolin
There are basically two different shotcrete processes: the wet-mix and the dry-mix processes. Wet-mix shotcrete is a process in which all of the ingredients, including water, are mixed before introduction into the delivery hose and compressed air is introduced to the material flow at the nozzle. Dry-mix shotcrete is a process in which most of the mixing water is added at the nozzle. It should be noted that the term “Gunite” is sometimes used in parts of North America and elsewhere in the world in lieu of dry-mix shotcrete. The reasons for this are discussed in Chapter 3. The term dry-mix shotcrete, rather than gunite will, however, be used throughout this book, as it is the term recommended for use for this process by the American Concrete Institute and American Shotcrete Association, as well as other organizations in North America.
Acid Rock Drainage and Metal Migration
Published in Mritunjoy Sengupta, Environmental Impacts of Mining, 2021
Shotcrete is the name given to concrete pneumatically delivered through a hose and applied to a surface at high velocity. Shotcrete may be effective in the control of acid generation when applied as a cover to certain wastes. The advantage of shotcrete is that it can be applied to steep rock slopes or other surfaces that may be difficult to cover using other methods.
Portland Cement Concretes
Published in M. Rashad Islam, Civil Engineering Materials, 2020
In common practice, shotcrete refers to concrete or mortar conveyed through a hose and pneumatically thrown at a high velocity onto a surface as an innovative construction technique, as shown in Figure 5.15. Specifically, shotcrete is the wet mix, previously prepared or a ready-mixed concrete. Gunite is the mixture of dry ingredients, with which water is mixed just before leaving the hose. In summary: Shotcrete is the wet mix previously prepared or ready-mixed concreteGunite is the mixture of dry ingredients water is mixed with just before applying
Steel Fibre-Reinforced Shotcrete as an alternative to conventional concrete tunnel lining: a case study of Gulpur Hydropower Project
Published in Geomechanics and Geoengineering, 2020
Khyzer Ahmed Sheikh, Ahsan Saif
Shotcrete is used extensively in the construction industry for waterproofing purposes and for the stabilisation of slopes, tunnels and excavations due to its ease of application and providing early strength in a short time. Due to these attributes, shotcreting has become imperative in tunnelling and underground construction, and is used as a primary support lining and a waterproofing barrier for the excavated sections. Modern tunnelling without primary lining of sprayed concrete is inconceivable and therefore it has become a common practice in the industry. The final lining of the tunnel is constructed using reinforced concrete, after providing primary supports (rock bolts and shotcreting), to stabilise the excavated tunnel section against rock overburden or water pressure. Following industry practice, in the past, all the roadway and waterway tunnels constructed in Pakistan have used conventional-reinforced concrete lining as the final lining of tunnels. Gulpur Hydropower project is the first project of its nature in Pakistan where Steel Fibre-Reinforced Shotcrete (SFRS) has been used instead of in situ concrete lining, as the final lining, for its diversion tunnels.
Understanding the impact of adhesion on the mechanical behavior of shotcrete
Published in CIM Journal, 2022
E. Karampinos, B. H. Ko, J. Hadjigeorgiou
Shotcrete is concrete that is pneumatically applied at high velocity against an overhead, vertical, or horizontal surface. It has been used for decades as surface support in underground excavations in rock. After installation, it promotes multiple support mechanisms that preserve the rock confinement and contribute to the stability of underground openings. Shotcrete can resist load by adhering to the surface of the excavation, redistributing radial pressure, sustaining bending moments, and/or promoting block interlocking (Kaiser & Tannant, 2001). A comprehensive description of the various stabilization mechanisms of shotcrete has been provided by Stacey (2001).