Welcome to AMIE Study - AMIE India Students Forum

AMIE Study - AMIE India Students Forum

collapse collapse

* Shoutbox

Refresh History
  • JYOTI VERMA: agr kisi ko apna exam city and center change krana hom to use kya krna chahiye plz suggest.
    October 14, 2017, 01:16:11 PM
  • JYOTI VERMA: amie ka exam center kaise change kr skte hai agr kiisi ko pta ho to plz btaiye .
    October 14, 2017, 01:15:31 PM
  • anoop.goyal9: error in online fee payment for winter 2017 examination
    October 12, 2017, 07:23:34 AM
  • ramajit: [link]
    October 06, 2017, 12:34:12 PM
  • ramajit: yes.. results announced... me 2/3 passed in Sec-B prodn Engg... xo xo... wow....
    October 06, 2017, 12:34:09 PM
  • suji.sujithraj: Guys check your results... its announced...!!!
    October 06, 2017, 10:26:53 AM
  • ramajit: summer'17 result will come or not ?
    October 06, 2017, 06:44:28 AM
  • jitu12341: Result has been declared ♡♡♡♡
    October 06, 2017, 06:30:56 AM
  • jitu12341: breaking news results will be publshed in March 18 along with winter 17
    October 04, 2017, 12:54:36 PM
  • ramajit: any tentative date aware about Summer'17 result
    October 03, 2017, 03:13:48 PM
  • nelokulood: What is the last date to apply for lab and project for winter 2017 session
    October 02, 2017, 11:39:31 AM
  • nelokulood: When will amie summer  2017 results be published
    October 02, 2017, 11:38:50 AM
  • SnrTech: please upgrade my membership to super member I already made payments Rs.500/- into bank account
    September 27, 2017, 11:17:12 PM
  • jitu12341: Is there anybody having EL 404, circuit and field theory notes  please mail on [email protected]
    September 23, 2017, 05:53:34 AM
  • jitu12341: Result is expected in first week of October
    September 23, 2017, 05:48:39 AM
  • manirock87: Result kab aayega for summer 2017
    September 22, 2017, 06:59:35 AM
  • mudassir.search007: Do i need to pay a separate fee for the Section A examination after paying the re-registration Fee (SEC A)
    September 20, 2017, 10:25:06 PM
  • kirannm: sorry just checking
    September 16, 2017, 08:07:00 PM
  • kirannm: hjhhjdfhj
    September 16, 2017, 08:06:43 PM
  • kirannm: hiii
    September 16, 2017, 08:06:31 PM

* Search


* User Info

 
 
Welcome, Guest. Please login or register.
Did you miss your activation email?

* Board Stats

  • stats Total Members: 48504
  • stats Total Posts: 27280
  • stats Total Topics: 6591
  • stats Total Categories: 6
  • stats Total Boards: 31
  • stats Most Online: 626

Author Topic: notes on concrete  (Read 1207 times)

Description:
September 22, 2011, 12:42:33 PM
  • Super Member
  • Registered User
  • *
  • Posts: 36
    • View Profile
Advertisement
Consolidation Of Concrete

The term consolidation of concrete is used to mean the compaction between aggregate and aggregate; between aggregate and reinforcement; and between aggregate and forms.
The main aim of consolidation of concrete is to eliminate air bubbles and thus to give maximum density to the concrete. An intimate contact between concrete and reinforcement is ensured by proper consolidation.
The difference between voids and pores may be noted. The voids are the gaps between two individual particles. The pores represent the opening within the individual particles. The process of consolidation of concrete can be carried out either with hand or with the help of vibrators.
Hand consolidation: For unimportant works, the consolidation of concrete is carried out by hand methods which include ramming, tamping, spading and slicing with suitable tools.
The hand methods require use of a fairly wet concrete. It should however be remembered that wherever feasible, the hand compaction should be preferred because the use of vibrator my lead to the segregation of the aggregates. As a matter of fact, the concrete mixes which can be hand-compacted should not be compacted by the use of vibrators.
Vibrators: These are the mechanical devices which are used to compact concrete in the formwork. The advantages of vibrators over hand methods are as follows:

(1) It is possible by means of vibrators to make a harsh and stiff concrete mix, with a slump of about 40 mm or less, workable.

(2) The quality of concrete can be improved by use of vibrators as less water will be required or in other way, economy can be achieved by adopting a leaner mix when vibrators are used.

(3) The use of vibrators results in the reduction of consolidation time. Hence the vibrators are used where the rapid progress of work is of great importance.



The poker vibrates while it is being inserted. The internal vibrators should be inserted and withdrawn slowly and they should be operated continuously while they are being withdrawn. Otherwise holes will be formed inside the concrete. The vibrator can be placed vertically or at a slight inclination not exceeding 100 to the vertical with the view to avoid flow of concrete due to vibration int

These vibrators require more power because of loss of some power in vibrating the rigid shutters. They are also heavy and hence they cannot be clamped at as many points as possible for uniform compaction of concrete. The compaction by these vibrators is found to be effective only upto a distance of about 450 mm from the face of the formwork.

(4) Vibrating tables: These are in the form of a rigidly built steel platform mounted on flexible springs and they are found to be very electromagnetic action or electric motors. They are found to be very effective in compacting stiff and harsh concrete mixes and hence they are invariably used in the preparation of precast structural products in factories and test specimens in laboratories.
The tables are vibrated either mechanically or by placing the springs under the supports of tables. The frequency of vibration varies from 3000 to 7200 vibration per minute. The two parameters of vibrations are frequency and time and they are related as follows:
« Last Edit: January 01, 1970, 04:00:00 AM by Guest »


Prayrona
Pranati Roy (Banerjee)
Jr. Civil engineer
E-mail : [email protected]
Airport
kolkata-136
 

Related Topics

  Subject / Started by Replies Last post
1 Replies
331 Views
Last post June 30, 2009, 08:25:20 PM
by praveen
0 Replies
413 Views
Last post January 22, 2010, 02:06:20 PM
by salman8506
2 Replies
601 Views
Last post March 23, 2011, 06:28:25 PM
by ritwik007
0 Replies
191 Views
Last post October 01, 2010, 02:18:17 PM
by rumidutta085
6 Replies
1402 Views
Last post March 13, 2012, 07:08:01 PM
by sandipcg
5 Replies
1891 Views
Last post October 11, 2012, 01:34:03 PM
by mahavirbarta
1 Replies
1417 Views
Last post July 16, 2016, 09:15:04 AM
by SatishPatil

* Search

* Subscribe to Forum

Enter your email address:

Advertisement

* Recent Posts

exam center changement by JYOTI VERMA
[October 14, 2017, 01:42:08 PM]


Summer 2017 result declared on today (6th Oct'17) by ramajit
[October 06, 2017, 12:38:15 PM]


Re: How to make a donation for super membership by praveen
[September 30, 2017, 09:22:53 PM]


Re: How to make a donation for super membership by SnrTech
[September 27, 2017, 11:32:31 PM]


Re: Registration in Saudi council of engineers by mudassir.search007
[September 08, 2017, 11:54:15 AM]