7 th CAPSA 99: General Session 5: Innovation in Asphalt Pavement - - PowerPoint PPT Presentation

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7 th CAPSA 99: General Session 5: Innovation in Asphalt Pavement - - PowerPoint PPT Presentation

May 01, 2023 156 likes •910 views

7 th CAPSA 99: General Session 5: Innovation in Asphalt Pavement Design Towards Improved Mechanistic Design of Thin Asphalt Layer Surfacings based on Actual Tyre/Pavement Contact Stress - In - Motion (SIM) data in South Africa Morris De Beer

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7th CAPSA ’99: General Session 5: Innovation in Asphalt Pavement Design Towards Improved Mechanistic Design

  • f Thin Asphalt Layer Surfacings based
  • n Actual Tyre/Pavement Contact Stress
  • In - Motion (SIM) data in South Africa

Morris De Beer (CSIR)

Louw Kannemeyer (SANRA Ltd) Colin Fisher (CSIR)

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Stress - In - Motion (SIM) Technology

CSIR IR, Transpo portek tek, South h Africa ca

7th CAPSA: ‘99

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Stress – In – Motion (SIM) Technology = The measurement of 3D tyre/pavement contact stresses from moving vehicles

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SLIDE 4 # N14 # N7 # R12 # N12 # N10 # N12 # N1 # N2 # N9 # N10 # N14 # N14 # N1 # N10 # N10 # N2 # N2 # N6 # N1 # N4 # N1 # N12 # N14 # N1 # N17 # N5 # N3 # N11

North

MACRO-CLIMATE: SOUTH AFRICA

Namibië

West Coast East Coast

Capetown Durban

DRY DRY DRY DRY DRY DRY DRY DRY WET WET WET WET MODERATE MODERATE MODERATE MODERATE

Botswana

DRY DRY

WET WET

& MAJOR ROAD SYSTEM

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SLIDE 5

Surfacing Types of National Roads in South Africa (1997/8)

HMA (46,3%)

Chip & Spray Seals (45,6%) PCC (7,5%) CRCP (0,5%)

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SLIDE 6

HMA

Base and Subbase Types

  • f National Roads in

South Africa (1997/8)

29% 13% 7% 6% 6% 3% 27% 9%

G1/G2 Base on Stab Subbase (29%) G1/G2 Base on Nat gravel Subbase (27 %) HMA (13 %) PCC (9 %) C3/C4 Base on Nat gravel Subbase (7 %) C3/C4 Base on Stab gravel Subbase (6%) G3/G4/G5 Base on Nat Gravel Subbase (6%)

G3/ G4/ G5 o n Stab Subbase (3%)

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RUTTING

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Longitudinal Flow of Asphalt

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Longitudinal Flow of Asphalt

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Fatigue Cracking and aging

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SURFACE DISINTEGRATION

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How to address the problem?? SIM Technology: Vehicle-Road Surface Pressure Transducer Array (VRSPTA)

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315/80 R22.5 HVS TYRE ON VRSPTA

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425 /65 R22.5 HVS TYRE ON VRSPTA

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VRSPTA Mark III

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VERTICAL CONTACT STRESS: VARIABLE LOADING (315 TIRE)

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LATERAL CONTACT STRESS: (Across 315 TIRE)

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LONGITUDINAL CONTACT STRESS: (Along 315 Tire)

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SLIDE 19

TYRES

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SLIDE 20
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SLIDE 21

~20 % in 20 Years Increase: Tyre Inflation Pressure in South Africa:

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SLIDE 22

Tyres: Heavy vehicles: Axle Loads > 7 000 kg Survey: 1995

Distribution of heavy truck tyre types in South Africa

13.8% 9.7% 1.2% 38.5% 3.6% 9.00-11.00-20 11.00-R20 11.00-R22.5 12.00-R22.5 275/80-315/80 R22.5 385/80-445/65 R22.5 33.2%

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SLIDE 23

(25.5%) <11-R22.5 (38.0%) 12.00-R22.5 (32.9%) Wide Duals (3.6%) Wide Base

NOMINAL DISTRIBUTION OF TRUCK TYRE TYPES IN SOUTH AFRICA (1995/6)

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SLIDE 24

TYPI PICAL CAL CO CONT NTACT ACT STRESS ESS DA DATA

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SLIDE 25

CONTACT STRESS (kPa)

FIGURE 11

Maximum vertical stress at CONSTANT LOAD and various inflation pressures

1000 1200 1400 1600

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

200 400 600 800

720 kPa 620 kPa 520 kPa 420 kPa

Tyre width: 220 mm

PIN NUMBER ACROSS VRSPTA

INFLATION PRESSURE::

Tyre Load = 18 kN

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SLIDE 26

200 400 600 800 1000 1200 1400 1600 INFLATION PRESSURE: 720 kPa 620 kPa 520 kPa 420 kPa

Tyre width: 220 mm

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

CONTACT STRESS (kPa) PIN NUMBER ACROSS VRSPTA

FIGURE 12

Maximum vertical stress at CONSTANT LOAD and various inflation pressures Tyre Load = 49 kN

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SLIDE 27

INFLATION PRESSURE = 420 kPa

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 200 400 600 800 1000 1200 1400 1600

PIN NUMBER ACROSS VRSPTA

Tyre width: 220 mm

20kN 30kN 40kN 50kN WHEEL LOAD:

CONTACT STRESS (kPa)

FIGURE 13

Maximum vertical stress at CONSTANT INFLATION PRESSURE at various loads

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SLIDE 28

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

200 400 600 800 1000 1200 1400 1600

INFLATION PRESSURE = 620 kPa

20kN 30kN 40kN 50kN WHEEL LOAD:

Tyre width: 220 mm

PIN NUMBER ACROSS VRSPTA

CONTACT STRESS (kPa)

FIGURE 14

Maximum vertical stress at CONSTANT INFLATION PRESSURE and various loads

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SLIDE 29

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

200 400 600 800 1000 1200 1400 1600

PIN NUMBER OF VRSPTA

CONTACT STRESS (kPa)

420 kPa 520 kPa 620 kPa 720 kPa

TYRE INFLATION PRESSURE:

Maximum vertical stress of tyre with tread grooves at CONSTANT LOAD and various inflation pressures Tyre Load = 20 kN

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SLIDE 30

CONTACT STRESS (kPa) INFLATION PRESSURE = 520 kPa Vertical stress of tyre with tread grooves at CONSTANT INFLATION PRESSURE and various loads

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

200 400 600 800 1000 1200 1400 1600

PIN NUMBER OF VRSPTA

20 26 30 42

TYRE LOAD (kN):

15

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SLIDE 31

4 PA 4 PAD D SI SIM SYS M SYSTE TEM M

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VRSPTA Mark III

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SLIDE 33
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SLIDE 34
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SLIDE 35
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Deflectograph Truck (80kN, 650 kPa): Vertical Contact Stress

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Deflectograph Truck (80kN,650 kPa): Lateral Contact Stress

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Deflectograph Truck (80kN,650 kPa): Longitudinal Contact Stress

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DEFLECTOGRAPH (OCTOBER 1998) Test 038-z

200 400 600 800 1000 1200 20 40 60 80 100 Measured Tire Contact Stress (kPa) % Cumulative Frequency

Front Left Front Right Rear Left OuterRear Left Inner Rear Right Outer Rear Right Inner Inflation Pressure 600 kPa 600 kPa 690 kPa 690 kPa 690 kPa 690 kPa Tyre

520 kPa (Design) 600 kPa (Front) 690 kPa (Rear)

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SLIDE 40

400 500 600 700 800 900 1000 1100

VER TIC AL C ONT ACT ST R ESS (kPa)

20 40 60 80 100 120

PERCENTAGE REDUCTION (%) AG G2 C 3 SG7 SG9

G D A E S 1

GR GRANULAR ANULAR BA BASE E PA PAVEM EMENT ENT

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SLIDE 41

400 500 600 700 800 900 1000 1100

VERTICAL CONTACT STRE SS (kPa)

5 10 15 20 25 30 35

PERCENTAGE REDUCTION (%) AG BC C4 SG7 SG9

B A E S 3

BI BITUMEN UMEN BA BASE E PA PAVEM EMENT ENT

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MANTSOLE TRAFFIC CONTROLL CENTRE (TCC) ON NATIONAL ROAD NR 1 (N1)

Full Axle SIM

North

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WEIGH- BRIDGE SITE FOR SIM AT MANTSOLE ON THE N1

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MANTSOLE TCC

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TRUCK IDENTIFICATION INCLUDES:  Vehicle Registration number;  Date of measurement;  Time of measurement;  Vehicle classification (i.e 1:2:2:2)  Tyre inflation pressure and tyre temp

  • nly on selected trucks at the TCC.
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SLIDE 49

The following items are obtained with the SIM:  Axle Speed;  Axle Distance;  Axle weights;  Axle Group weights;  Tyre width;  Tyre contact area;  Tyre patch length (TPL);  Tyre weights;  3D Vertical, Lateral & Longitudinal Stresses;  Stress Ratios;

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SLIDE 50
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SLIDE 53

(19.4%) (2.8%) (16.7%) (22.2%) (33.3%) (5.6%)

1:1 1:1:2 1:2:2 1:2:3 1:2:2:2 1:2:3:2

SIM TESTS: BREAK DOWN OF VEHICLE CLASSES MEASURED (MANTSOLE, N1)

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SLIDE 54

5 10 15 20 25 30 35

MULTI-DECK (Tonne)

10 20 30

SIM LOADCELLS (Tonne)

1 to 1 Regression line (Rsqr = 0,956) Validated Data (26 Trucks)

MAN1.WK4

MANTSOLE WEIGHBRIDGE (TCC)

SIM TESTS NOV. & DEC. 1998 & FEB 1999

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SLIDE 55

200 400 600 800 1000 1200

Pin numbers Stress (kPa)

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2

AXLE 5

Vertical Maximum Contact Stress (kPa)

001-z DMB 453 GP Left Outer

Tyre Left Inner Tyre Right Inner Tyre Right Outer Tyre

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SLIDE 56

100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

10 20 30 40 50 60 70 80 90 100

Contact Stress (kPa) % Cumulative Frequency

ax1l ax1r ax2l ax2li ax2ri ax2r ax3l ax3li ax3ri ax3r ax4l ax4li ax4ri ax4r ax5l ax5li ax5ri ax5r ax6l ax6li ax6ri ax6r ax7l

MANTSOLE TESTING (NOV 98)

FILE 001-Z (COMBINATION 1 2 2 2)

CUM-001.WK4 DMB 453 GP

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SLIDE 57

Summary of SIM data: Mantsole, TCC on N1:

  • SIM Data of 36 trucks - 704 tyres analyzed;
  • SIM Accuracy vs Multi-deck Scale: within

2,5 %;

  • SIM Precision @ 95 % = 2,6 tonne /Axle Group;
  • Vertical Stress: 577 – 1149 (Ave. = 903 kPa);
  • Lateral Stress: 89 – 233 (Ave. = 170 kPa);
  • Longitudinal Stress: 52 – 237 (Ave. = 124 kPa);
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SLIDE 58

Summary of SIM data: Mantsole, TCC on N1 Continue:

  • Stress Ratios: 10:1,88:1,38
  • Average Max Vertical > 1,59 x Inflation

Pressure;

  • Max Vertical Stress/520 kPa : 1,37 to 2,75

(NCP);

  • Vertical Stress Patterns of approx. 22 % of

tyres show “abnormal” patterns;

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SLIDE 59

40 200 1 300 100 600 1 300 Non-Uniform Vertical Stress Tyre Edge C L Depth (mm)

Radial Distance (mm)

Lateral stress

FIGURE: 29

Axi-symmetrical Finite Element Model used in this study

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Pseudo-Energy under non-uniform contact stress conditions (Symplectic Engineering Corporation, USA)

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Colour maps of Shape distortion (Symplectic Engineering Corporation)

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Summary & Conclusions:

  • SIM Technology proven to be successful locally and
  • verseas;
  • Ratio of Stresses: Vert : Lat : Long = 10 : 2 : 1,5
  • SIM results useful to Civil Engineers and road

building;

  • Challenge to develop detailed design and analyses

methods utilizing SIM data;

  • Finite Element Analysis Methods (FEM) to be used

more widely with SIM data in road design;

  • SIM systems should be improved for wider use such as

“WIM”;

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SLIDE 73

I Thank You all !!

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Thank you !!