Sanral Consultants perspective of seal design •Minimum • Tack Coat = 0,90 l/m2 Class S-E1 hot...

Sanral – Consultants perspective

How to make it work

This presentation will deal with problems experienced presently

1

Limits of seal design

• Minimum• Tack Coat = 0,90 l/m2 Class S-E1 hot applied polymer modified

bitumen binder

• Penetration Layer = 0,900 l/m2 Class S-E1 hot applied polymer modified bitumen binder

• Fog Spray = 1,0 l/m3 Cat 33 emulsion

• Maximum• Tack Coat = 1,20 l/m2 Class S-E1 hot applied polymer modified

bitumen binder



2

Recommended Seal design

• Recommended

• Tack Coat = 1,10 l/m2 Class S-E1 hot applied polymer modified bitumen binder



• Total net binder

3

Embedment of road

4

Typical variation in texture of road

5

Rich surface

6

Bleeding of surface (Fatty)

7

Apply all information and designs to determine actual spray application for a

specific section of road taking into account:-

• Minimum and maximum spray rates

8




• Texture

9




• Texture

• Physical condition e.g.. Rich, bleeding

10




• Texture


• Embedment

11




• Texture


• Embedment

• Use recommended spray rate most of the time

12




• Texture


• Embedment


• Apply Colto TRH 3 adjustments e.g. grades, climbing lanes, cold areas, no traffic, fatty surfaces, construction traffic

13




• Texture


• Embedment


• Apply Colto TRH 3 adjustments e.g. grades, climbing lanes, cold areas, no traffic, fatty surfaces, construction traffic

• Mark (spray) application rate on road or record

14

SABS 307

15

Compare different base bitumen – SABS 307

16

Bitumen blend

Check

•Viscosity

•Viscosity

•Viscosity• Temperature

• Softening Point

17

Taking samples after first spray application when spray bar is on temperature

18

Measuring Dynamic Viscosity

19

Typical results for a periodDynamic Viscosity (Haake @ 1900C) before spray

(green) and during spray (blue) for a period.V

IS

CO

SIT

Y (d

Pa

.s)

0

10

20

30

40

50

60

70

80

90

Max 40

Min 20

Number of days sprayed 20

Dynamic Viscosity curve for a specific batch

21

Non conformance - Dynamic Viscosity

22

Non conformance - Dynamic Viscosity

23

Specifications in TG 1, Project documentation and TRH 3 e.g. for Bitumen

rubber, SBR, SBS……etc.

24

Use different blends of base bitumen to achieve specifications

Base Bitumen Blend - 50:50, Natref:Calref





Base Bitumen Calref


Truck Broken Send Back





Base Bitumen Blend - 30:70 Natref:Calref

Base Bitumen Blend - 30:70 Natref:Calref


Check Samples Before Spray

25

Softening Point 0C

26Number of days sprayed

Soft

en

ing

Po

int

0C

Softening Point 0C

27

Remember: We want cheese cake with our bitumen

28

But: You cannot make cheese cake out of horse manure

29

Calibrate the temperature meter

30

To low temperature cause a poor application

31

Cold spray bar

32

Checklist – prior to seal

• Measure road width

33



• Mark applications or record

34




• Set out parallel lanes

35





• Guardrails, bridge balustrades, access roads

36





• Constrains e.g. guardrails, bridge balustrades, access roads

• Traffic control

37





• Constrains e.g. guardrails, bridge balustrades, access roads

• Traffic control

• Calculate quantity bitumen needed for day

38

Checklist – During construction

• Discuss and agreewidthlength

39


• Discuss and agreewidth length

• Method of joint construction

40



• Method of joint

• Longer section to avoid joints (300 -400m)

41



• Method of joint

• Longer section to avoid joints (300 -400m)

• Establish working procedure

42

Distributors varies - 6m wide spray bar

43

Make sure all parties are readyand informed

44

Use the same size aggregate on reinforced bitumen paper

45

Test spray bar / nozzles prior to spray

46

Apply an uniform tack coat without / with joints

47

Typical look of uniform applied rubber bitumen tack coat

48

Make sure of 1/3, 2/3 and fullapplication on joint – this will only

appear if viscosity is within specification

49

Demarcation string with first application of aggregate

50

Apply uniform layer of aggregate and take special care of joint

51

Apply uniform layer of aggregate

52

Keep the 1/3 and 2/3 application on joint free from aggregate

53

Keep 27t rollers as near as possible to chip operation (Hot binder only)

54

Roll, roll…………roll.

55

Use reinforced bitumen paper on all joints

56

Trim all joints

57

Construction of centre line joint

58

Typical look of centre line joint with binder application

59

Completed centre line jointDo not construct joints on top of each other

60

Always be present at the construction of the new seal

61

Must do before and after each spray

• Visually check for viscosity problems. Measure viscosity and record

62



• Calculate binder application rate (l / m2)

63



• Calculate binder application rate (l /m2)

• Calculate aggregate application rate (m2 / m3)

64



• Calculate binder application rate (l/m2)

• Calculate aggregate application rate (m2 / m3)

• Take corrective action immediately if application rates and / or viscosity does not conform to the specifications or design

65

Check the temperature regular

66

TYPICAL DEFECTS

And Corrective action

67

Things shall go wrong

68

Corrective action

69

Non Conformance70

Corrective Action71

Trim corrective action work neatly

72

Protect completed work

73

Nozzles did not open

74

Chip spreader gate did not open

75

Distributor missed the centre line joint in curve

76

Spray areas without binder with single or double nozzle to correct the defect

77

The Engineer?

78

Avoid sharp turning on newly constructed seals

79

Fog spray

• Broom - remove all loose aggregate

80

Fog spray


• Roll with light steel drum roller (5 – 8 ton) after back chipping

81

Fog spray



• Apply fog spray

- Up to 0.8 l/m2 Cat 33% or Cat 35%

82

Fog spray



• Apply fog spray


- 0.8 – 1,2 l/m2 Cat 45%

83

Fog spray



• Apply fog spray


- 0.8 – 1,2 l/m2 Cat 45%

• Open to traffic 24 - 48 hours later

84

After care

• Second application of fog spray

85

After care


• Free from all loose aggregate

86

After care


• Free from all loose aggregate

• Newly constructed seals need traffic

87

Construction of seals

Consultants perspective

Thanks

ERO Engineers (Pty) Ltd

Freddie Henning88

Sanral Consultants perspective of seal design •Minimum • Tack Coat = 0,90 l/m2 Class S-E1 hot...

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Transcript of Sanral Consultants perspective of seal design •Minimum • Tack Coat = 0,90 l/m2 Class S-E1 hot...