Concrete compaction - Revision history

Editor: Reverted edits by 157.32.231.141 (talk) to last revision by 49.34.195.138

2022-01-11T13:58:07Z

Reverted edits by 157.32.231.141 (talk) to last revision by 49.34.195.138

← Older revision		Revision as of 13:58, 11 January 2022
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	= Introduction =		= Introduction =

−	Compaction is a process of expelling entrapped air. If we don’t expel ~~these~~ air ~~voids from concrete~~, it will result into ~~[https://www.civilexperiences.com/2021/02/honeycombs-in-concrete-type-cause-prevent-reme.html~~ honeycombing] and reduced strength. It has been found from the experimental studies that 1% air in concrete reduces the strength by approximately 6%.	+	Compaction is a process of expelling entrapped air. If we don’t expel this air, it will result into honeycombing and reduced strength. It has been found from the experimental studies that 1% air in concrete reduces the strength by approximately 6%.

	There are two methods of compaction:		There are two methods of compaction:
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	= Hand compaction =		= Hand compaction =

−	Hand compaction is used for simple, small structures. ~~[https://www.civilexperiences.com/2021/02/workability-of-concrete-types-factors-affecting.html~~ Workability] should be decided in such a way that the chances of honeycombing is minimised.	+	Hand compaction is used for simple, small structures. Workability should be decided in such a way that the chances of honeycombing is minimised.

	Methods of hand compaction include:		Methods of hand compaction include:

157.32.231.141 at 13:55, 11 January 2022

2022-01-11T13:55:58Z

← Older revision		Revision as of 13:55, 11 January 2022
Line 1:		Line 1:
	= Introduction =		= Introduction =

−	Compaction is a process of expelling entrapped air. If we don’t expel ~~this~~ air, it will result into honeycombing and reduced strength. It has been found from the experimental studies that 1% air in concrete reduces the strength by approximately 6%.	+	Compaction is a process of expelling entrapped air. If we don’t expel these air voids from concrete, it will result into [https://www.civilexperiences.com/2021/02/honeycombs-in-concrete-type-cause-prevent-reme.html honeycombing] and reduced strength. It has been found from the experimental studies that 1% air in concrete reduces the strength by approximately 6%.

	There are two methods of compaction:		There are two methods of compaction:
Line 12:		Line 12:
	= Hand compaction =		= Hand compaction =

−	Hand compaction is used for simple, small structures. Workability should be decided in such a way that the chances of honeycombing is minimised.	+	Hand compaction is used for simple, small structures. [https://www.civilexperiences.com/2021/02/workability-of-concrete-types-factors-affecting.html Workability] should be decided in such a way that the chances of honeycombing is minimised.

	Methods of hand compaction include:		Methods of hand compaction include:

49.34.195.138 at 05:02, 25 February 2021

2021-02-25T05:02:55Z

← Older revision		Revision as of 05:02, 25 February 2021
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	* Hand compaction.		* Hand compaction.
−	* Mechanical compaction.	+	* Mechanical compaction i.e vibration method
		+	* Compaction by pressure and jolting method
		+	* Compaction by a spinning method

	= Hand compaction =		= Hand compaction =
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	* Platform vibration: Similar to table vibrators but these are generally used on a very large scale.		* Platform vibration: Similar to table vibrators but these are generally used on a very large scale.
	* Surface vibration: These are also called screed board vibrators. The action is similar to that of tamping. The vibrator is placed on screed board and vibration is given on the surface. It is mainly used for roof slabs, road pavements etc., but it is not effective beyond 15 cm depth.		* Surface vibration: These are also called screed board vibrators. The action is similar to that of tamping. The vibrator is placed on screed board and vibration is given on the surface. It is mainly used for roof slabs, road pavements etc., but it is not effective beyond 15 cm depth.
		+
		+	= Compaction by pressure and jolting method =
		+
		+	* In this method, stiff concrete is subjected to external pressure from the top and vibration from the bottom along with a series of jolting actions
		+	* Excess water added during mixing exits due to large pressure
		+
		+	= Compaction by a spinning method =
		+
		+	* Compaction by Spinning is also called centrifugation
		+	* This method Compaction by Spinning is used in the manufacture of concrete pipes, concrete lamp posts etc
		+	* The initial w/c ratio of 0.35 to 0.40 reduced to about 0.30 after spinning

	= Related articles on Designing Buildings Wiki. =		= Related articles on Designing Buildings Wiki. =
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	* Testing concrete.		* Testing concrete.
	* The properties of concrete.		* The properties of concrete.
		+	* source [https://www.civilexperiences.com/ Civil Experience]

−	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:Construction_techniques]]	+	[[Category:Articles_needing_more_work]] [[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:Construction_techniques]]

Designing Buildings at 07:35, 6 February 2021

2021-02-06T07:35:32Z

← Older revision		Revision as of 07:35, 6 February 2021
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	* The properties of concrete.		* The properties of concrete.

−	[[Category:Construction_techniques]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:Construction_techniques]]

Designing Buildings: moved COMPACTION OF CONCRETE to Concrete compaction

2020-03-09T10:59:46Z

moved COMPACTION OF CONCRETE to Concrete compaction

← Older revision

Revision as of 10:59, 9 March 2020

Designing Buildings at 10:59, 9 March 2020

2020-03-09T10:59:12Z

← Older revision		Revision as of 10:59, 9 March 2020
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	* Platform vibration: Similar to table vibrators but these are generally used on a very large scale.		* Platform vibration: Similar to table vibrators but these are generally used on a very large scale.
	* Surface vibration: These are also called screed board vibrators. The action is similar to that of tamping. The vibrator is placed on screed board and vibration is given on the surface. It is mainly used for roof slabs, road pavements etc., but it is not effective beyond 15 cm depth.		* Surface vibration: These are also called screed board vibrators. The action is similar to that of tamping. The vibrator is placed on screed board and vibration is given on the surface. It is mainly used for roof slabs, road pavements etc., but it is not effective beyond 15 cm depth.
		+
		+	= Related articles on Designing Buildings Wiki. =
		+
		+	* 3D concrete printer.
		+	* Architectural concrete.
		+	* Cast-in-place concrete.
		+	* Cellular concrete.
		+	* Concrete.
		+	* Concrete in aggressive ground (SD 1).
		+	* Concrete-steel composite structures.
		+	* Concreting plant.
		+	* Precast concrete.
		+	* Prestressed concrete.
		+	* Power float.
		+	* Reinforced concrete.
		+	* Scabbling.
		+	* Self-compacting concrete.
		+	* Stratification of concrete.
		+	* Testing concrete.
		+	* The properties of concrete.

	[[Category:Construction_techniques]]		[[Category:Construction_techniques]]

Designing Buildings at 10:57, 9 March 2020

2020-03-09T10:57:32Z

← Older revision		Revision as of 10:57, 9 March 2020
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−	= ~~[https://worl.data.blog/2019/04/09/compaction-of-concrete/ COMPACTION OF CONCRETE]~~ =	+	= Introduction =

−	Compaction is a process of expelling ~~the~~ entrapped air. If we don’t expel this air, it will result into honeycombing and reduced strength. It has been found from the experimental studies that 1% air in ~~the~~ concrete ~~approximately~~ reduces the strength by 6%.	+	Compaction is a process of expelling entrapped air. If we don’t expel this air, it will result into honeycombing and reduced strength. It has been found from the experimental studies that 1% air in concrete reduces the strength by approximately 6%.

−	~~DIFFERENT METHODS OF CONCRETE COMPACTION~~	+	There are two methods of compaction:

−	~~There are two methods of~~ compaction ~~adopted in the field as given below~~.	+	* Hand compaction.
		+	* Mechanical compaction.

−	* Hand compaction	+	= Hand compaction =
−	* Mechanical Compaction	+

−	~~(A) HAND COMPACTION~~	+	Hand compaction is used for simple, small structures. Workability should be decided in such a way that the chances of honeycombing is minimised.

−	~~Hand compaction is used for ordinary and unimportant structures. Workability should be decided in such a way that the chances of honeycombing should be minimum. The various methods~~ of hand compaction ~~are as given below.~~	+	Methods of hand compaction include:

−	1. ~~RODDING~~	+	* Rodding: 'Poking' with a 2m long, 16 mm dia rod at sharp corners and edges. The thickness of layers for rodding should be 15 to 20 cm.
		+	* Ramming: Generally used for compaction on ground in plain concrete. It is not used either in RCC or on upper floors.
		+	* Tamping: The top surface is beaten by a wooden cross beam of cross section 10 cm x 10 cm. Both compaction and levelling are achieved simultaneously. It is mainly used for roof slabs and road pavements.

−	~~It is a method of poking with 2m long, 16 mm dia rod at sharp corners and edges. The thickness of layers for rodding should be 15 to 20 cm.~~	+	= Mechanical compation =

−	2. ~~RAMMING~~	+	Vibration is imparted to the concrete by mechanical means. This causes temporary liquefaction so that air bubbles come to the top and are expelled.

−	~~It is generally used for compaction on ground in plain concrete. It is not used either in RCC or on upper floors.~~	+	Mechanical vibration techniques include:

−	3. ~~TAMPING~~	+	* Internal vibration: The most commonly used technique of concrete vibration. Vibration is achieved by eccentric weights attached to a shaft. The needle diameter varies from 20 mm to 75 mm and its length varies from 25 cm to 90 cm. The frequency range adopted is normally 3500 to 5000 rpm.
		+	* External vibration: This is adopted where internal vibration can’t be used due to either thin sections or heavy reinforcement. External vibration is less effective and it consumes more power compared to the internal vibration. The formwork also has to be made extra strong when external vibration is used.
		+	* Table vibration: Mainly used for laboratories where concrete is put on the table.
		+	* Platform vibration: Similar to table vibrators but these are generally used on a very large scale.
		+	* Surface vibration: These are also called screed board vibrators. The action is similar to that of tamping. The vibrator is placed on screed board and vibration is given on the surface. It is mainly used for roof slabs, road pavements etc., but it is not effective beyond 15 cm depth.

−	It is a method in which the top surface is beaten by wooden cross beam of cross section 10 cm x 10 cm. both compaction and leveling are achieved simultaneously. It is mainly used for roof slabs and road pavements.	+	[[Category:Construction_techniques]]
−		+
−	~~(B) MECHANICAL COMPACTION~~	+
−		+
−	Vibration is imparted to the concrete by mechanical means. It causes temporary liquefaction so that air bubbles come on to the top and expelled ultimately. Mechanical vibration can be of various types as given under.	+
−		+
−	~~1. INTERNAL VIBRATION~~	+
−		+
−	It is most commonly used technique of concrete vibration. Vibration is achieved due to eccentric weights attached to the shaft. The needle diameter varies from 20 mm to 75 mm and its length varies from 25 cm to 90 cm. the frequency range adopted is normally 3500 to 5000 rpm. The correct and incorrect methods of vibration using internal vibration needles are shown below.	+
−		+
−	~~2. EXTERNAL VIBRATION~~	+
−		+
−	This is adopted where internal vibration can’t be used due to either thin sections or heavy reinforcement. External vibration is less effective and it consumes more power as compared to the internal vibration. The form work also has to be made extra strong when external vibration is used.	+
−		+
−	~~3. TABLE VIBRATION~~	+
−		+
−	~~It is mainly used for laboratories where concrete is put on the table.~~	+
−		+
−	~~4. PLATFORM VIBRATION~~	+
−		+
−	~~It is similar to table vibrators but these are generally used on a very large scale.~~	+
−		+
−	~~5. SURFACE VIBRATION~~	+
−		+
−	These are also called screed board vibrators. The action is similar to that of tamping. The vibrator is placed on screed board and vibration is given on the surface. It is mainly used for roof slabs, road pavements etc., but it is not effective beyond 15 cm depth.	+
−		+
−	~~<Humayoon Sial>~~	+
−		+
−	~~<humayoonsial.civil@gmail.com>~~	+
−		+
−	~~[[Category:Conservation]] [[Category:Definitions]] [[Category:Education]] [[Category:Theory]]~~ [[Category:Construction_techniques]]	+

Humayoon at 14:13, 27 November 2019

2019-11-27T14:13:44Z

← Older revision		Revision as of 14:13, 27 November 2019
Line 51:		Line 51:

	<Humayoon Sial>		<Humayoon Sial>
		+
		+	<humayoonsial.civil@gmail.com>

	[[Category:Conservation]] [[Category:Definitions]] [[Category:Education]] [[Category:Theory]] [[Category:Construction_techniques]]		[[Category:Conservation]] [[Category:Definitions]] [[Category:Education]] [[Category:Theory]] [[Category:Construction_techniques]]

Humayoon: Created page with "= [https://worl.data.blog/2019/04/09/compaction-of-concrete/ COMPACTION OF CONCRETE] = Compaction is a process of expelling the entrapped air. If we don’t expel this air, it w..."

2019-11-27T14:12:07Z

Created page with "= [https://worl.data.blog/2019/04/09/compaction-of-concrete/ COMPACTION OF CONCRETE] = Compaction is a process of expelling the entrapped air. If we don’t expel this air, it w..."

New page

= [https://worl.data.blog/2019/04/09/compaction-of-concrete/ COMPACTION OF CONCRETE] =

Compaction is a process of expelling the entrapped air. If we don’t expel this air, it will result into honeycombing and reduced strength. It has been found from the experimental studies that 1% air in the concrete approximately reduces the strength by 6%.

DIFFERENT METHODS OF CONCRETE COMPACTION

There are two methods of compaction adopted in the field as given below.

* Hand compaction
* Mechanical Compaction

(A) HAND COMPACTION

Hand compaction is used for ordinary and unimportant structures. Workability should be decided in such a way that the chances of honeycombing should be minimum. The various methods of hand compaction are as given below.

1. RODDING

It is a method of poking with 2m long, 16 mm dia rod at sharp corners and edges. The thickness of layers for rodding should be 15 to 20 cm.

2. RAMMING

It is generally used for compaction on ground in plain concrete. It is not used either in RCC or on upper floors.

3. TAMPING

It is a method in which the top surface is beaten by wooden cross beam of cross section 10 cm x 10 cm. both compaction and leveling are achieved simultaneously. It is mainly used for roof slabs and road pavements.

(B) MECHANICAL COMPACTION

Vibration is imparted to the concrete by mechanical means. It causes temporary liquefaction so that air bubbles come on to the top and expelled ultimately. Mechanical vibration can be of various types as given under.

1. INTERNAL VIBRATION

It is most commonly used technique of concrete vibration. Vibration is achieved due to eccentric weights attached to the shaft. The needle diameter varies from 20 mm to 75 mm and its length varies from 25 cm to 90 cm. the frequency range adopted is normally 3500 to 5000 rpm. The correct and incorrect methods of vibration using internal vibration needles are shown below.

2. EXTERNAL VIBRATION

This is adopted where internal vibration can’t be used due to either thin sections or heavy reinforcement. External vibration is less effective and it consumes more power as compared to the internal vibration. The form work also has to be made extra strong when external vibration is used.

3. TABLE VIBRATION

It is mainly used for laboratories where concrete is put on the table.

4. PLATFORM VIBRATION

It is similar to table vibrators but these are generally used on a very large scale.

5. SURFACE VIBRATION

These are also called screed board vibrators. The action is similar to that of tamping. The vibrator is placed on screed board and vibration is given on the surface. It is mainly used for roof slabs, road pavements etc., but it is not effective beyond 15 cm depth.

<Humayoon Sial>

[[Category:Conservation]] [[Category:Definitions]] [[Category:Education]] [[Category:Theory]] [[Category:Construction_techniques]]