What is the purpose of keeping tremie pipe’s tip immersed in freshly-placed concrete for about 1m in underwater concreting?

  What is the purpose of keeping tremie pipe’s tip immersed in freshly-placed concrete for about 1m in underwater concreting? The size of tremie pipe is about 300mm with sections having flange couplings fitted with gasket to prevent water leakage. The tremie pipe should be closed initially to prevent water from entering the pipe. It should be designed with sufficient thickness and weight so that it would not be buoyant when empty inside water. The placement of tremie concrete is commenced by putting the closed pipe underwater to the location for concreting, followed by partial filling of tremie pipe with concrete. In order to have tremie concrete flowed out of the pipe, it is necessary to fill the pipe with concrete of sufficient height to overcome the water pressure and frictional head. After that the tremie pipe is raised about 150mm to allow concrete to flow out. To enhance sufficient bonding, each succeeding layer of concrete should be placed before the preceding layer has rea...
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QUALITY CHECKLIST FOR,CEMENT,STEEL,BINDING WIRE,SAND,AGGREGATE,DOOR SHUTTER


QUALITY  CHECKLIST

1. Norms  For  Field  Tests  For Various  Materials

Given  hereunder are  the details  of physical  field  tests  which  must  be  carried  out  at  site  for various  materials.  The  tables  also, show  the required  results  of all  the  tests.  Actual  results  at site  may  differ  and, hence, a  separate  column  to  record  these  observations  is  also  provided  in  these  tables.  The  required  results  are  based  on  practical  acceptance  and  these may  vary  from  site  to  site  or  when compared  to standard norms.


2.    Field  Tests  For  Cement
         
ENGG / FR / 1


Work-site:

Field  Tests For  Cement                            Report  No:              Dated:

Sr No
Detail  of  test
Required  result
Actual  result
 1
Grade
33 grade
43  grade
53 grade

2
Freshness  by  noting  manufacturing  date
Week, month and year  are printed.

3
Freshness  by  lump  test
No  lumps should  be  present

4
Fineness  by  feeling  between  fingers
Should  feel  silky.

5
Fineness  test  by  immersing  hand  in bag.
Should  feel  cool.

6
Weight  of each  bag
Should  be  50 kg

7
Float  test
Should  float  on  water  before  sinking.


8

Paste  test
Should  gain  some strength after  24-hr curing.

9
Type  of  bag
Jute
Polythene
Paper

10
Original stitching
Should  be  intact

Other  comments :

Contractor’s  Engineer:
Site Engineer:

3.    Field  Tests  For   Binding Wire and Reinforcement  Steel

ENGG / FR / 1


Work-site:

Field  Tests  For  Binding Wire and Reinforcement  Steel         
    Report No:                                                                          Dated:

Sr No
Detail  of  test
Required  result
Actual  result
1
Gauge of wire
Normally,17swg, or as ordered

2
Bending test for hardness
Should be soft for twisting

3
“Tor”  or  other marks
Should  be  rolled  on  all  lengths at  one  meter  intervals


4
Pitch  of  twist  of  bar
Should  be 8  to  12  times  the bar diameter.

5
Colour
Should  be  steel  grey

6

Actual  unit  weight
Should  not  deviate  from  the  theoretical  unit  weight  by  more  that  5%.


7
Rusting
Should not be  found

8
Nominal  diameter
Should  be  as  noted

9
Bend  test for  hardness
Should  bend  smoothly  and  should  not  crack  while  bending.

10
Length  of bar
Should be 11  to 12 meters.

Other  comments :

Contractor’s  Engineer:
Site Engineer:

4.    Field  Tests  For  Sand
         
ENGG / FR / 3


Work-site:

Field  Tests  For   Sand         Report  No:                          Dated:

Sr No
Detail  of  test
Required  result
Actual  result


1


%  silt content
Should  not  exceed  6%  by  volume. 
Should be washed beyond  3%.



2


Fineness  test  by  feel
Should  be  neither  too  coarse  nor too fine.
Very fine sand  not  advisable  for  RCC  works.


3

Organic  impurities
Should  be  within limits.
Shell/ shingle  should  be visually identifiable.

Other  comments :

Contractor’s  Engineer:
Site Engineer:
 Note:  In  case of  works  such  as  waterproofing and   plastering, every  truckload  of  sand  should  be  checked  for  silt content and a register  should be maintained.  For  other  works, the  silt  content  must be  checked  after every  20   trips.

5.  Field  Tests  For  Coarse  Aggregate

ENGG / FR /4


Work-site:

Field  Tests  For  Coarse  Aggregate         
Report No:                                                                           Dated:
                                                                

Sr No
Detail  of  test
Required  result
Actual  result

1

Shape
Should be angular, flaky  and hard.

2
Size
Should be  as  required.

3
Gradation
Should  be  as required.



4


Quality of stone
Should  be  blackish grey.
Should be uniform  in colour
Should  be  hard.
Should not get muddy when mixed with water


5

24-hour absorption
Should  be  less  than  5%  by weight.

Other  comments :

Contractor’s  Engineer:
Site Engineer:

6.    Field  Tests  For  Murum


ENGG / FR / 5


Work-site:

Field  Tests  For  Murum     Report  No:                          Dated:

Sr No
Detail  of  test
Required  result
Actual  result

1

Quality
Should  not get  muddy  when  mixed  with water.


2

Size
Should  be  between  5 mm  and  65 mm.

3
Hardness
Particle should be sufficiently hard.

Other  comments :

Contractor’s  Engineer:
Site Engineer:

7.    Field  Tests  For  Flush  Door  Shutters
     
ENGG / FR / 6


Work-site:

Field  Tests  For  Flush  Door  Shutters              Report No:              Dated:                                                     

Sr No
Detail  of  test
Required  result
Actual  result
1
Type
Solid core
Hollow-core



2


Cladding
Both sides  commercial ply.
One  side  teak ply.
Both  sides teak  ply.

3
Size  and  thickness
Should  be  as per order.


4

Edges  and top  layer
Should  be  straight and sharp.
Top layer should not be damaged.


5

Defects
Should be free from twisting and warping.

Other  comments :

Contractor’s  Engineer:
Site Engineer:
 8.    Field  Tests  For  Bricks

ENGG / FR / 7


Work-site:

Field  Tests  For  Bricks            Report  No:                          Dated:

Sr No
Detail  of  test
Required  result
Actual  result
1
Colour
Should  be red
Should  be  uniform.


2

Edges
Should  be  sharp
Should be straight.
Should be  at  right angles.


3

Type
Country
Table  moulded
Engineering

4
 Size
230 x 100 x 90 mm
230 x 150 x 100 mm

5
Frog
10 mm  to 20  mm


6

Water  absorption
Should  be  no  more  than 20%  by weight.


7

Soundness
Should give clear, metallic  ringing  sound


8

Burning
Should  not  be over-burnt.
Should not be under-burnt.

9
%  breakage
Should be no  more than  5%


10

Strength
Should  not  break  under  a  free  fall  of    600  mm  on the  flat face.

Other  comments :

Contractor’s  Engineer:
Site Engineer:
 9.    Field  Tests  For  Lime

ENGG / FR / 8

Work-site:
Field  Tests  For  Lime            Report  No:                          Dated:
Sr No
Detail  Of  Test
Required  result
Actual  result

1
Colour
Should  be  even  and  uniformly white.


2
Strength
Should  harden  within  12 hours  after  application.


3
Consistency
Should be judged by visual observation.

4
Freshness
No lumps  should  be observed

5
Brand
As  specified

6
Weight  per  bag
Normally  10 Kg / as specified

Other  comments :

Contractor’s  Engineer:
Site Engineer:
10.  Tests  for  Concrete  Blocks

ENGG / FR / 9


Work-site:

Field  Tests  For  Concrete  Blocks                 Report  No:               Dated:

Sr No
Detail  of  test
Required  result
Actual  result
1
Size
As  specified

2
Type
Hollow-core
Solid  core


3

Edges
Should  be  sharp
Should be straight.
Should be  at  right angles.

4
Texture
Should  be  homogeneous.

5
Defects
Should  be free  from cracks.


6

Strength
Should  not  break  under  a  free  fall  of    1000  mm  on the  flat face.

7
Water  absorption
Should  be  no more than  10%.


8

Weight  per  block
As specified.
Should be noted after complete curing  of  each lot.

9
%  breakage
Should be no more than  3%

Other  comments :

Contractor’s  Engineer:
Site Engineer:


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