Shotcrete technology - Revision history

Designing Buildings at 07:47, 10 March 2023

2023-03-10T07:47:41Z

← Older revision		Revision as of 07:47, 10 March 2023
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	The use of air-entraining admixtures (AEA) in shotcrete is practical only in wet-mix shotcrete. When batched properly, AEA forms an air-void system suitable for providing frost resistance to wet-mix shotcrete. The formation of an air-void system in dry-mix shotcrete is not possible.		The use of air-entraining admixtures (AEA) in shotcrete is practical only in wet-mix shotcrete. When batched properly, AEA forms an air-void system suitable for providing frost resistance to wet-mix shotcrete. The formation of an air-void system in dry-mix shotcrete is not possible.

−	= Related articles on Designing Buildings ~~Wiki~~ =	+	See also: Sprayed in situ concrete.
		+
		+	= Related articles on Designing Buildings =

	* Basement waterproofing.		* Basement waterproofing.
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	* Self-compacting concrete.		* Self-compacting concrete.
	* Shotcrete global market.		* Shotcrete global market.
		+	* Sprayed in situ concrete.
	* Tunnelling.		* Tunnelling.

−	[[Category:Articles_needing_more_work~~]] [[Category:Conservation~~]] [[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Construction_techniques]] [[Category:Products_/_components]]	+	[[Category:Articles_needing_more_work]] [[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Construction_techniques]] [[Category:Products_/_components]] [[Category:Conservation]]

Designing Buildings: Reverted edits by Junhuamachinery (talk) to last revision by 151.41.139.62

2021-03-31T07:18:44Z

Reverted edits by Junhuamachinery (talk) to last revision by 151.41.139.62

← Older revision		Revision as of 07:18, 31 March 2021
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	= Introduction =		= Introduction =

−	~~[https://www.junhuamachinery.com~~ Shotcrete] is a mortar or high performance concrete conveyed through a hose and pneumatically projected at high velocity onto a backing surface. It is the force of this spraying action that leads to compaction of the concrete or mortar which then forms layers of concrete to the required thickness .	+	Shotcrete is a mortar or high performance concrete conveyed through a hose and pneumatically projected at high velocity onto a backing surface. It is the force of this spraying action that leads to compaction of the concrete or mortar which then forms layers of concrete to the required thickness .

−	~~ShotcretingShotcreting~~ has proved to be the best method for construction of curved surfaces. Tunnel linings and domes are now much easier to construct with the advent of with shotcrete technology.	+	Shotcreting has proved to be the best method for construction of curved surfaces. Tunnel linings and domes are now much easier to construct with the advent of with shotcrete technology.

	Shotcrete is a widely accepted and used way of placing material that is cementitious in nature for a vast variety of applications.		Shotcrete is a widely accepted and used way of placing material that is cementitious in nature for a vast variety of applications.

−	Since 1900, the year it was invented by American taxidermist Carl ~~Akeley, it has seen many improvements, be it in the equipment or in the specialised techniques required for the pneumatic application of mortar or concrete.~~Akeley, it has seen many improvements, be it in the equipment or in the specialised techniques required for the pneumatic application of mortar or concrete.	+	Since 1900, the year it was invented by American taxidermist Carl Akeley, it has seen many improvements, be it in the equipment or in the specialised techniques required for the pneumatic application of mortar or concrete.

	Today it has become a vital material because of it being versatile in shape, high strength, durable, good bonding ability, and in areas of difficult access it can be easily sprayed onto a surface at high velocity, making it handy for operation.		Today it has become a vital material because of it being versatile in shape, high strength, durable, good bonding ability, and in areas of difficult access it can be easily sprayed onto a surface at high velocity, making it handy for operation.

Junhuamachinery at 07:11, 31 March 2021

2021-03-31T07:11:59Z

← Older revision		Revision as of 07:11, 31 March 2021
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	= Introduction =		= Introduction =

−	Shotcrete is a mortar or high performance concrete conveyed through a hose and pneumatically projected at high velocity onto a backing surface. It is the force of this spraying action that leads to compaction of the concrete or mortar which then forms layers of concrete to the required thickness .	+	[https://www.junhuamachinery.com Shotcrete] is a mortar or high performance concrete conveyed through a hose and pneumatically projected at high velocity onto a backing surface. It is the force of this spraying action that leads to compaction of the concrete or mortar which then forms layers of concrete to the required thickness .

−	~~Shotcreting~~ has proved to be the best method for construction of curved surfaces. Tunnel linings and domes are now much easier to construct with the advent of with shotcrete technology.	+	ShotcretingShotcreting has proved to be the best method for construction of curved surfaces. Tunnel linings and domes are now much easier to construct with the advent of with shotcrete technology.

	Shotcrete is a widely accepted and used way of placing material that is cementitious in nature for a vast variety of applications.		Shotcrete is a widely accepted and used way of placing material that is cementitious in nature for a vast variety of applications.

−	Since 1900, the year it was invented by American taxidermist Carl Akeley, it has seen many improvements, be it in the equipment or in the specialised techniques required for the pneumatic application of mortar or concrete.	+	Since 1900, the year it was invented by American taxidermist Carl Akeley, it has seen many improvements, be it in the equipment or in the specialised techniques required for the pneumatic application of mortar or concrete.Akeley, it has seen many improvements, be it in the equipment or in the specialised techniques required for the pneumatic application of mortar or concrete.

	Today it has become a vital material because of it being versatile in shape, high strength, durable, good bonding ability, and in areas of difficult access it can be easily sprayed onto a surface at high velocity, making it handy for operation.		Today it has become a vital material because of it being versatile in shape, high strength, durable, good bonding ability, and in areas of difficult access it can be easily sprayed onto a surface at high velocity, making it handy for operation.

151.41.139.62 at 15:35, 1 March 2021

2021-03-01T15:35:37Z

← Older revision		Revision as of 15:35, 1 March 2021
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	* Tunnelling.		* Tunnelling.

−	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Construction_techniques]] [[Category:Products_/_components]]	+	[[Category:Articles_needing_more_work]] [[Category:Conservation]] [[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Construction_techniques]] [[Category:Products_/_components]]

Designing Buildings at 05:51, 7 October 2020

2020-10-07T05:51:05Z

← Older revision		Revision as of 05:51, 7 October 2020
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	* Tunnelling.		* Tunnelling.

−	[[Category:~~Construction_techniques~~]] [[Category:~~Products_/_components~~]] [[Category:DCN_Product_Knowledge]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Construction_techniques]] [[Category:Products_/_components]]

Designing Buildings at 06:34, 23 May 2019

2019-05-23T06:34:18Z

← Older revision		Revision as of 06:34, 23 May 2019
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	The use of air-entraining admixtures (AEA) in shotcrete is practical only in wet-mix shotcrete. When batched properly, AEA forms an air-void system suitable for providing frost resistance to wet-mix shotcrete. The formation of an air-void system in dry-mix shotcrete is not possible.		The use of air-entraining admixtures (AEA) in shotcrete is practical only in wet-mix shotcrete. When batched properly, AEA forms an air-void system suitable for providing frost resistance to wet-mix shotcrete. The formation of an air-void system in dry-mix shotcrete is not possible.

−	~~= Find out more =~~	+	= Related articles on Designing Buildings Wiki =
−		+
−	=== Related articles on Designing Buildings Wiki ===	+

	* Basement waterproofing.		* Basement waterproofing.
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	* Reinforced concrete.		* Reinforced concrete.
	* Self-compacting concrete.		* Self-compacting concrete.
		+	* Shotcrete global market.
	* Tunnelling.		* Tunnelling.

−	[[Category:Construction_techniques]] [[Category:Products_/_components]]	+	[[Category:Construction_techniques]] [[Category:Products_/_components]] [[Category:DCN_Product_Knowledge]]

92.234.28.136 at 21:53, 11 July 2017

2017-07-11T21:53:16Z

← Older revision		Revision as of 21:53, 11 July 2017
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	Shotcrete floors in tanks and pools on well compacted sub-base or on undisturbed earth have generally given excellent service.		Shotcrete floors in tanks and pools on well compacted sub-base or on undisturbed earth have generally given excellent service.

−	Vertical and overhead construction for walls, slabs ,columns, and other structural members has been frequently shotcreted.	+	Vertical and overhead construction for walls, slabs, columns, and other structural members has been frequently shotcreted.

	=== Shotcrete domes ===		=== Shotcrete domes ===
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	=== Reinforcing steel ===		=== Reinforcing steel ===

−	Reinforcing bars for shotcrete should meet the same specifications as for conventional concrete. Because of the placement method, the use of bars larger than ~~16mm~~ diameter or heavy concentrations of steel are not practical.	+	Reinforcing bars for shotcrete should meet the same specifications as for conventional concrete. Because of the placement method, the use of bars larger than 16 mm diameter or heavy concentrations of steel are not practical.

−	Large bars make it difficult to achieve adequate build-up of good quality shotcrete behind the bar and heavy concentrations of steel interfere with the placement of shotcrete. In general, bar spacings of ~~150mm~~ to ~~300mm~~ are recommended for shotcrete reinforcement.	+	Large bars make it difficult to achieve adequate build-up of good quality shotcrete behind the bar and heavy concentrations of steel interfere with the placement of shotcrete. In general, bar spacings of 150 mm to 300 mm are recommended for shotcrete reinforcement.

	=== Chemical admixtures ===		=== Chemical admixtures ===
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	== Strength ==		== Strength ==

−	In terms of compressive and flexural strength, shotcrete can produce strength generally equivalent to conventional concrete. Compressive strengths of ~~up to 12,000 psi have been reported from drilled cores from test panels,~~ and ~~10,000 psi~~ is ~~often quoted in the literature as a typical high strength~~.	+	In terms of compressive and flexural strength, shotcrete can produce strength generally equivalent to conventional concrete. Compressive strengths of between 30 and 60 N/mm² is generally achievable.

−	The practicality of strengths over 5,000 psi should be established by laboratory or field testing prior to final use. The ratio between compressive and flexural strength appears to be the same as for conventional concrete.	+	Relationships between water-cement ratio and strength follow normal patterns, with higher strength associated with lower water-cement ratios.
−		+
−	Relationships between water-cement ratio and strength ~~also appear to~~ follow normal patterns, with higher strength associated with lower water-cement ratios~~. Early strength of shotcrete can be very high, reaching 1,000 psi in 5 hours and 3,000 psi in 24 hours~~.	+

	== Bond strength ==		== Bond strength ==
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	== Wet mix proportioning ==		== Wet mix proportioning ==

−	Mixture proportioning procedures for the formulation of conventional concrete for pumping applications are applicable for wet-mix shotcrete. The nominal ~~maximum~~ aggregate size is usually ~~3/4 inch or smaller~~. The batched cement content will typically range from ~~500~~ to ~~700 pounds per cubic yard~~.	+	Mixture proportioning procedures for the formulation of conventional concrete for pumping applications are applicable for wet-mix shotcrete. The nominal aggregate size is usually 10 mm. The batched cement content will typically range from 350 to 450 kg/m³.

	Rich mixtures are common for shotcrete, especially if vertical or overhead shotcrete placement is required. The limiting factor for cement content in a mixture is often governed by the amount of cement necessary for the shotcrete to adhere to a wall or ceiling, not the specified compressive strength.		Rich mixtures are common for shotcrete, especially if vertical or overhead shotcrete placement is required. The limiting factor for cement content in a mixture is often governed by the amount of cement necessary for the shotcrete to adhere to a wall or ceiling, not the specified compressive strength.
−
−	~~It is not unusual for shotcrete used in vertical and overhead placement to have 28-day strengths in excess of 4,500 psi, due only to the amount of cement necessary to make the shotcrete adhere.~~

	== Dry mix proportioning ==		== Dry mix proportioning ==
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	Rebound is the shotcrete material that 'bounces' off the shooting surface. Rebound for conventional dry-mix shotcrete, in the best of conditions, can be expected to be at least 20% of the total material passed through the nozzle. Wet-mix shotcrete rebounds somewhat less than dry-mix shotcrete.		Rebound is the shotcrete material that 'bounces' off the shooting surface. Rebound for conventional dry-mix shotcrete, in the best of conditions, can be expected to be at least 20% of the total material passed through the nozzle. Wet-mix shotcrete rebounds somewhat less than dry-mix shotcrete.

−	The use of air-entraining admixtures (AEA) in shotcrete is practical only in wet-mix shotcrete. When batched properly, AEA forms an air-void system suitable for providing frost resistance to wet-mix shotcrete. The formation of an air-void system in dry-mix shotcrete is not possible~~. However, dry-mix shotcrete, when properly proportioned and applied, will have a compressive strength exceeding approximately 7,000 pounds per square inch (psi) performed well~~.	+	The use of air-entraining admixtures (AEA) in shotcrete is practical only in wet-mix shotcrete. When batched properly, AEA forms an air-void system suitable for providing frost resistance to wet-mix shotcrete. The formation of an air-void system in dry-mix shotcrete is not possible.

	= Find out more =		= Find out more =

92.234.28.136 at 21:34, 10 July 2017

2017-07-10T21:34:10Z

← Older revision		Revision as of 21:34, 10 July 2017
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−	[[File:Shotcrete.jpg]]	+	[[File:Shotcrete.jpg\|link=File:Shotcrete.jpg]]

	= Introduction =		= Introduction =
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	=== Reinforcing steel ===		=== Reinforcing steel ===

−	Reinforcing bars for shotcrete should meet the same specifications as for conventional concrete. Because of the placement method, the use of bars larger than ~~No. 5~~ or heavy concentrations of steel are not practical.	+	Reinforcing bars for shotcrete should meet the same specifications as for conventional concrete. Because of the placement method, the use of bars larger than 16mm diameter or heavy concentrations of steel are not practical.

−	Large bars make it difficult to achieve adequate build-up of good quality shotcrete behind the bar and heavy concentrations of steel interfere with the placement of shotcrete. In general, bar spacings of 6 to ~~12 inches~~ are recommended for shotcrete reinforcement.	+	Large bars make it difficult to achieve adequate build-up of good quality shotcrete behind the bar and heavy concentrations of steel interfere with the placement of shotcrete. In general, bar spacings of 150mm to 300mm are recommended for shotcrete reinforcement.

	=== Chemical admixtures ===		=== Chemical admixtures ===

Editor at 14:28, 21 June 2017

2017-06-21T14:28:54Z

← Older revision		Revision as of 14:28, 21 June 2017
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		+	[[File:Shotcrete.jpg]]
		+
	= Introduction =		= Introduction =

Editor at 14:26, 21 June 2017

2017-06-21T14:26:19Z

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