This document discusses potential miner mistakes that can occur during the production of concrete sleepers and their effects. It covers issues that may happen during mould preparation, wire tensioning, batch mixing, steam curing, demoulding, and inspection. Mistakes like misaligned wire positions, bent moulds, improper tensioning, subpar vibration, and curing issues can result in reduced strength or defects in the final sleepers. Attention to proper procedures and equipment maintenance is necessary to avoid problems and ensure sleepers meet quality standards.

1. Effects of miner mistakes On-
Track
Presented by
Lakavath.Chandrashekhar
Graduate Engineer Trainee

3. Contents
Mould Preparation
Stressing of HTS-wire
Batch Mixing
Steam Curing
Demoulding and transfer of pre-stress
Water curing
Inspection and testing of sleepers
Stocking

4. Mould Preparation
Few what I observed in my Experience are…!
Wire position of sleepers: How it Effects in strength criteria
if Centre of Gravity of HTS wire group and Tensioning jock miss-matches then what
are the effects…?
Mould and Bench Dimensions:

5. While Stressing of wire
If center of gravity coincides then what
happens…?

6. While Stressing of wire
If center of gravity mismatches then what
happens…?

7. Bending of Bench may be concave or convex in
Any Directions

8. Benches having Bend Box Angle
Box angle bent upwards
Elongation Difference

10. Tensioning
 Tensioning: Load per jack 250KN
Bench jack
After Tensioning final Elongation Of HTS wire is improper
1. To avoid this we have to provide I-Beams in all bench’s. Now this work in progress in
GAYA Plant
2. Few props are bend, bench’s are bend(Max No of bench’s are not in good condition)
3. Load was releasing after tensioning due to improper props(in gaya better to provide
flat surface in-place of dip surfaces)
props
Dip surfaced prop flat surfaced prop

11. Vibration
1. RPM of all vibrators is good but not developing full vibration since
size of shaft well which generates vibration was not good condition
2. In few bench’s base plates of vibrators are touching with bench’s
3. Vibrators are not started even after filling the moulds with concrete.
Supervisors are not identifying how much time the vibrators are
running. For this provide Auto Stating option like in WADIARAM or
provide display to show the running time vibrator.
4. We checked RPM Of vibrators results are
Vibrator RPM
V-1 9235
V-2 9270
V-3 9076
V-4 9013
V-5 9197
V-6 9242
V-7 9317
V-8 9196

12. Vibrator plates touching to
bench’s
Vibrator plate
DE-MOULDING:
Some times they are cutting wire without loosing Main –Bolts. We asked workers
who are working in that area answering as if bolts are not loosed in 2 kiks then

13. Batch Mixing
STANDARD MIXING SEQUENCE
SAND+COARS
E
AGGREGATE
(30sec)
½ OF TOTAL
WATER
(30sec)
BINDING
MATERIAL
(CEMENT)
(30sec)
½ OF TOTAL
WATER &
ADDMIXTURE
(30sec)
MIXING
(1MIN)

14. Hydraulic Machines
Calibration as per NCCBM certification
Hydraulic oil Maintenance (Add video observed in proving
ring) effect of impact load on cubes, Tensioning area and
SBT area
Due to impact load we can not observe the original strength
in Cube,SBT
Machineries to be checked
regularly

15. CURING
If any of these properties neglected then Desired
property can not developed
Curing Requires Adequate
1.Moisture
2.Temparature
3.Time

16. Curing Methods and Materials
Ponding Sealed Curing
Sprayingimmersion Steam curing
Gunny Bags

17. Steam Curing
Steam curing is advantageous where:
 Early Strength gain in concrete
 Additional Heat of hydration is required, as in cold weather
Live steam curing cycle consist of:
Initial delay period to steaming:
Increasing the Temperature:
Holding the maximum temperature constant:
Decreasing the Temperature:
2.High pressure steam curing in autoclaves (used in rubber industries)
Two Methods of Steam curing are used:
1.Live steam curing at atmospheric pressure (used in Sleeper industries)

18. Moist heat:
Live steam curing provides an additional advantage over
other curing methods, as this method supplies both the
necessary heat and moisture required for successful
accelerated curing.
Live steam curing enclosures can be constructed closed
one where the steam is circulated through holes in
distribution piping.
Initial set can be determined in accordance with IS 4031
(Cement Testing code).

19. Boiler

21. Gravity fall arrangement of Bikets in
boiler

22. To avoid Heat loss what can we do at Boiler…?

23. Time(h)
Temperature (°C)
≤71°C for AASHTO
≤70°C for CSA and PCI
≤22°C/h for
AASHTO
≤15°C /h for CSA
≤22°C/h for
AASHTO
≤20°C/h for CSA
≥10 °C ≥11 °C
Pre-
steaming
Raising Constant cooling
Live steam curing at Atmospheric pressure

24. What Is Ettringite…?
Ettringite is the mineral name for calcium
sulfoaluminate (3CaO•Al2O3•3CaSO4•32H2O), which is
normally found in port land cement concretes.
How it is formed…?
What its Effect on Sleepers…?

26. High pressure steam curing in autoclaves
(used in rubber industries)

27. De-moulding and transfer of prestress

30.  After de-moulding stocking of sleeper was not good.

31. Water curing

33. Surface honeycombs due to less quality Mould oil
Less Quality Mould Oil
on surface of mould
Surface Honeycomb

34. Checking Critical Dimensions:
Outer Gauge:
How it may effect After installing in site.
Rail-seat:
How it plays it role in site, why should we strict with those dimensions
Toe-Gap:
What will happens if exceeds dimensions in future in site

35. Slope Failed sleepers Effect in Site

36. Failure In FTC

40. Over End Type Rejection
Over End : While Casting Sleeper End Plate Bolts are
getting loose

41. Good Stocking

44. Surface Defect
End Honeycombs
Surface Honeycombs

46. Effect of End Broken sleepers in
site

50. Extra End Wire Projections
Projections of HTS wire>3mm Projections of HTS wire<3mm

51. After Grouting of HTS wire will rust
(I observed these things in project period)

52. Pitting corrosion on strands due to
chloride attack

53. Any Suggestions …!
Feel free to contact:
chandujntum@gmail.com
p16st016@amd.svnit.ac.in

54. THANK
YOU MY
DEARS