Answer / c. mak

Increased exposure to carbon dioxide from the air reduces
the pH of the concrete mix through carbonation. The reduced
pH causes the steel to corrode. May also be a result of
increased use of salts during the winter season.

Answer / koushik

in olden days the sections were huge and cover to the
reinforcement was much high......but now sections becoming
tooo slender and min cover is being provided.so this may b
one of the reason for the early deterioration of steel.

Answer / rajesh ghyar, global group

The reasons are as follows
1)Sub standard quality of reinforcement steel , Rerolling
material.Untested steel are using.
2) Poor workmen ship to provide reinforcement in proper
position.
3)No specified cover to steel.
4) Improper casting of RCC member.
5) Pollution in atmosphere.
6)Lack of supervision.

Answer / pordeep

nowadays usage of bribery,corrupption is more in indian
contarctors,politicians like kapil sibal,yeddurappa,reddy
chaddi,chidambaram,sonia gandhi,lalu gadkari,is more so les
quality cement stel is coming

what u guys say... cheers bhago bharat bhago

Answer / naveen

Ca (oH)2 is a by product of cement hydration product .if we contains less amount of calcium hydroxide (basic nature) decreases ultimately acidic nature increases 7-6-5------3-2-1 u know that 1 means have higher acidic nature .so 7 to 1 values increases acidic nature also increases then more acidic vices corrosion...kk

Answer / varun joshi

hi guys it is true that in olden days reinforment bars are
provided but there life span is increases because the ph
value of the constrution water is litil higher that time
its simple thying that we know nowdays h2so4 in atmosphere
is rised due to both reasons now days we providing reainfo
but it not give the strenght for the longer
period.....................

Answer / venky

my dear friends der was no usuage of steel in olden
days ... dan from wer question arises of rusting

Answer / prashant

the reason is that 2 much of water is used in mixing of
concrete so tht for better workmenship!!!so more moisture
conent!!!!nd the other reason may be the chemical used in
cement@

Answer / nisha a.s

One of the main reason is the corrosive environment.
Inadequate cover to the reinforcement also leads to
corrosion.

Answer / ishak

due to admixures used(nowadays) to improve the strength or
other property make the bars rusted

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08. 4 main points about check list for Shuttering works are––– 4 i) ii) iii) iv) 09. 4 main points about check list for Concreting works are––– 4 i) ii) iii) iv) 10. 4 main points about check list for Plaster works are––– 4 i) ii) iii) iv) 11. 4 main points about check list for Brick works are–– – 4 i) ii) iii) iv) 12. 3 main points about Project delaying factors are––– 3 i) ii) iii) 13. Write down 60-grade M.S. deformed bar specification. 3 14. 3000 psi concrete means: 1 15. 4 main points about methods of wastage control are–– – 4 i) ii) iii) iv) 16. 1 main point about reasons for your honesty is : 1 17. Water cement mixing in hopper less mixture machine is better than hopper mixture machine because: 1 18. 2 main points about your role during roof casting are–––– 2 i) ii) 19. a. The weight of 3333m deform bar of 24.5 mm dia is…… 1 b. The weight of 300 rft plain bar of dia 1 is……. 1 20. The types of slumps are––– 3 i) ii) iii) 21. 4 main points about the causes of cylinder failure are––– 2 i) ii) iii) iv) 22. Detection of a beam & a girder are–––– 2 i) ii) 23. Curing is needed for–––– 1 24. The types of slabs in respect of size & shape are––– 5 In respect of size: i) ii) In respect of Shape i) ii) iii) 25. The types of Column in respect of size & shape are–– – 9 In respect of size: i) ii) In respect of Shape: i) ii) iii) iv) v) vi) vii) 26. 3 field tests & 3 Laboratory tests of bricks are––– 6 Field tests: i) ii) iii) Lab test: i) ii) iii) 27. 2 field tests & 1 Laboratory tests of sand are––– 3 Field tests: i) ii) Lab test: i) 28. 1 field tests & 1 Laboratory tests of M.S rod are––– 2 Field tests: i) Lab test: i) 29. a. The % of water absorbs by brick chips: …………… 1 b. The % of water absorbs by Stone chips: …………… 1 30. In respect of design: 5 a. The % of strength gains by concrete in 28 days= b. The % of strength gains by concrete in 14 days= c. The % of strength gains by concrete in 07 days= d. The % of strength gains by concrete in 03 days= e. The % of strength gains by concrete in 28 days without curing =

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