1. PROJECT OVERVIEW N3/3 ATHLONE TO HILTON Dennis Rossmann

2. N3/3 ATHLONE TO HILTON

3. CONTRACT No NRA N0303012/6: REHABILITATION OF ROUTE 3, SECTIONS 3& 4 ATHLONE TO HILTON km 19,130 (N3/3) TO km 1,160 (N3/4) CONTRACT DETAILS Employer: SANRAL Contractor: Basil Read / Milling Techniks : Consortium Consulting Engineers: BLN Consortium (Ingérop Africa, Letsunyane Associates (Pty) Ltd and Preben Naidoo & Associates) Tender Sum: R65 535 800-64

4. CONSTRUCTION HISTORY Construction by Provincial Roads Department NBC commenced – 1957 completed – 1962 SBCcompleted – 1971 Subsequent reseal and overlay

6. TRAFFIC ADT – 22 560 ADTT – 3058

10. TOPOGRAPHY Grades – 7% max Up to 6% over 40% of length Superelevation – Up to 12%

13. TRAFFIC ACCOMMODATION Closures to one lane limited to outside peak periods Two lanes open in each direction outside working hours Facility for removal of broken down vehicles

16. GEOTECHNICAL INSTABILITY Infilled gullies Talis creep Requires continuous management

18. PAVEMENT DESIGN Rigid pavement overlay Block paving Flexible pavement (Asphalt overlay) Composite pavement (Concrete / asphalt)

21. COMPOSITE PAVEMENT Appropriate pavement Cost benefit Labour enhancement

24. CRCP INLAY EXPERIENCE Riding quality / smoothness Longitudinal joint ( rigid / flexible) Pop-outs Subsurface drainage

29. QUALITY CONTROL

33. GEOMETRIC DESIGN Peter Unstead

34. GEOMETRIC DESIGN PHILOSOPHY PARTIAL CONCRETE INLAYS TO PRESCRIBED LEVELS FINISHED ROAD LEVEL TO BE RAISED ENABLING:  SMOOTHING OF VERTICAL ALIGNMENT  ELIMINATION OF UNDULATIONS CAUSED BY FILL SUBSIDENCES  REGULARISATION OF THE SUPERELEVATION TO A LIMITED EXTENT CARRIAGEWAYS TO BE WIDENED WITHIN GEOTECHNICAL AND BUDGET CONTSTRAINTS

35. HORIZONTAL AND VERTICAL ALIGNMENT CARRIAGEWAYS HAD BEEN CONSTRUCTED IN SEPARATE SECTIONS UNDER VARIOUS CONTRACTS AND OVER AN EXTENDED PERIOD OF TIME A TRULY GEOMETRICAL MODEL OF THE VERTICAL ALIGNMENT COULD NOT BE ESTABLISHED WITHOUT RESULTING IN EXCESSIVELY THICK OVERLAYS  EXISTING ROAD LEVELS "SMOOTHED" BY GRAPHICAL METHODS  SUPERELEVATION CORRECTIONS APPLIED  VARIOUS THICKNESSES OF OVERLAY LESS THE 80mm MILLING DEPTH ADDED TO PRODUCE THE FINISHED ROAD LEVELS.

36. DESIGN METHODOLOGY DETAILED TOPOGRAPHICAL SURVEY USING GPS METHODS TO CREATE A DIGITAL TERRAIN MODEL OF THE EXISTING ROAD AND WIDENING AREAS. POINTS SURVEYED:  AT EACH EDGE OF ROAD  ON THE LANE MARKINGS  IN THE INVERT AND ON THE OUTER EDGES OF THE EXISTING SIDE DRAINS. A “BEST-FIT” GEOMETRIC HORIZONTAL ALIGNMENT DERIVED FOR EACH CARRIAGEWAY  THE CENTRE-LINE CHOSEN BETWEEN THE SLOW LANE AND THE CENTRE LANE  THE NBC REALIGNED BETWEEN km 23,2 AND km 23,7 TO CONTINUE THE THREE LANE SECTION PAST THE HILTON INTERCHANGE BY WIDENING THE CARRIAGEWAY IN THE MEDIAN.

37. DESIGN METHODOLOGY USING ROAD DESIGN SOFTWARE EXISTING ROAD LEVELS DETERMINED ON CENTRE-LINE, FUTURE LANE MARKING POSITIONS AND EDGES OF THE CARRIAGEWAY LEVELS TRANSFERRED TO A SPREADSHEET  COLUMN PROVIDED TO ADJUST THE DESIGN CENTRE LINE LEVEL RELATIVE TO EXISTING LEVEL TO PRODUCE A SMOOTH LONGITUDINAL PROFILE  EXISTING CROSSFALLS ASSESSED FOR UNIFORMITY WITH RESPECT TO LHS AND RHS OF CENTRE LINE AND COMPLIANCE WITH STANDARDS.  DESIGN CROSSFALLS CHOSEN  DESIGN LEVELS DERIVED AT VARIOUS OFFSETS LEFT AND RIGHT OF CENTRE-LINE  EDGE LEVELS DETERMINED BY THE CROSSFALLS CHOSEN.

38. DERIVATION OF DESIGN LEVELS DIFFERENCES BETWEEN EXISTING ROAD LEVELS AND THE PROPOSED DESIGN LEVELS CALCULATED AND INFLUENCE ON PAVEMENT DESIGN ASSESSED THE SMOOTHNESS OF THE LONGITUDINAL PROFILES ON CENTRE-LINE AND AT THE EDGES ASSESSED GRAPHICALLY BY APPLYING A SLOPING DATUM LINE. ADJUSTMENTS APPLIED AND CHECKED UNTIL A SATISFACTORY PROFILE WAS OBTAINED.

39. SMOOTHING OF LEVELS N3/3 SOUTHBOUND CARRIAGEWAY

45. WIDENING OF THE CARRIAGEWAYS EXTENT SUBJECT TO GEOTECHNICAL AND BUDGET CONSTRAINTS NORTHBOUND CARRIAGEWAY  BETWEEN RICKIVY VIADUCT AND km 21,2 WIDENING WOULD ENTAIL EXTENSIVE EARTHWORKS AND RETAINING WALLS  NORTH OF km 21,2 TO HILTON INTERCHANGE:  TO EASE TRAFFIC CONGESTION, A 3m WIDE SLOW SHOULDER WAS MORE ESSENTIAL ON THE LONG SUSTAINED 6% GRADE WHERE HEAVY VEHICLES TEND TO TRAVEL TWO ABREAST UP TO HILTON  HEAVY VEHICLES BREAK DOWN MORE OFTEN IN THIS AREA THAN FURTHER SOUTH  THICK MIST MORE PREVALENT

46. WIDENING OF THE CARRIAGEWAYS EXISTING 15,1m WIDTH AVAILABLE FROM km 21,7 TO km 23,4  A RELATIVELY FLAT AREA AVAILABLE ON THE RIGHT HAND SIDE OF THE NBC TO ALLOW WIDENING IN THE MEDIAN AVOIDING WIDENING OF CUTTINGS AND CONSTRUCTION OF RETAINING WALLS ON THE LEFT HAND SIDE  EXTENSION OF THE EXISTING 15,1m WIDE SECTION BACK TO km 21,2 AND FROM km 23,2 OVER THE RIDGE TO THE DOWNGRADE APPROACHING CEDARA COST EFFECTIVE DUE TO RELATIVELY MINOR EARTHWORKS INVOLVED

47. WIDENING OF THE CARRIAGEWAYS SOUTHBOUND CARRIAGEWAY  LIMITED TO EXTENDING EXISTING 15,1m WIDTH FROM km 24,7 TO km 25,5 AT HILTON  HEAVY VEHICLES GENERALLY CONFINED TO CRAWLER LANE BETWEEN RICKIVY VIADUCT AND HILTON  HEAVY VEHICLES SELDOM BREAK DOWN  WIDENING THE 12,0m WIDE CARRIAGEWAY BETWEEN km 21,2 AND km 22,9 CONSTRAINED BY VERY HIGH FILLS ON RHS AND THE NEED TO AVOID CUTTING INTO THE HILLSIDE ON LHS  WIDENING OF THE 11,0m WIDE CARRIAGEWAY BETWEEN THE ARRESTOR BED AND km 21,2 CONSTRAINED BY DEEP SEATED FILL INSTABILITY

50. Pavement Design and Details Herman Wolff

51. PRESENTATION OVERVIEW  Pavement design principles  Design traffic  Pavement models  Flexible pavement design method  Rigid pavement design method  Resulting pavement structures  Design details

52. PAVEMENT DESIGN PRINCIPLES  CRC partial inlays used in slow lanes – Slow moving heavy traffic on steep incline – High ambient temperatures – CRC to allow for future overlays  CRC partial inlay in NBC centre lane – Heavies overtaking on uphill sections – Joint between slow and centre lanes concrete to concrete  Asphalt base and surfacing used in SBC centre lane – Lower traffic because of dedicated crawler lane – Easier traffic accommodation.  Asphalt surfacing used in fast lanes – Low traffic loading

53. DESIGN TRAFFIC  Cumulative E80’s over 15 years – Slow lanes:40 million – NBC centre lane:20 million – SBC centre lane:10 million – Fast lanes:1 million

54. PAVEMENT MODELS  Derivation of pavement models for mechanistic analysis – As-built information – Backcalculated elastic layer moduli from FWD testing – Asphalt cores

55. FLEXIBLE PAVEMENT DESIGN – Asphalt and cemented layers SAMDM stochastic transfer functions based on linear elastic material behaviour and failure in fatigue – Granular layers Stochastic transfer functions based on non- linear elasto-plastic material behaviour and failure in permanent deformation – Subgrade layers Transfer function based on linear elastic material behaviour and failure in permanent deformation

56. ASPHALT TRH4 Revision (1995): Phase 1: Updating Transfer Functions for SAMDM.

61. RIGID PAVEMENT DESIGN  Manual M10 – Deterministic – Nomograms – Underlying pavement modelled by a single semi-infinite layer with an “equivalent support stiffness”  CNCRISK computer program – Developed by C and CI – Stochastic (Monte Carlo Simulation) – Computerised – Underlying pavement modelled by multiple layers characterised by thickness and stiffness (MPa)

62. PAVEMENT STRUCTURES - FLEXIBLE  Fast lanes – 30 SMA, 20 – 40 asphalt levelling layer – 30 SMA, 60 asphalt base, asphalt levelling layer  Fast lane widenings – 30 SMA, 60 asphalt base, 150 C3 subbase, 300 G7 and G9 selected layers, subgrade (improved)  SBC middle lane – 30 SMA, 150 asphalt base – 30 SMA, 100 asphalt base, 250 C3 subbase (reworked)

63. PAVEMENT STRUCTURES - RIGID  Thickness varies between 180 and 220 mm depending on loading and support  30 mm asphalt bedding layer where no existing asphalt  Existing structure

64. Number123 CarriagewayNBC SBC LaneSlowCentreSlow Chainage (km)21.700 – 21.900 21.100 – 21.300 20.160 – 21.280 Pavement structure200 CRC 30 AS 200 G2 150 G3 / G5 150 G7 150 G9 180 CRC 30 AS 200 C4 150 G3 / G5 150 G7 150 G9 190 CRC 100 AC 130 G2 150 G3 / G5 150 G7 150 G9 Design Traffic (Million E80’s) 402040 INFLUENCE OF SUPPORTING LAYERS

67. THANK YOU

68. CONSTRUCTION Philip Wyatt

69. ROAD WIDENING:NBC Fast lane and shoulder - 4,0km NBC Slow shoulder - 0,5km SBC Fast shoulder - 0,8km CONCRETE PAVEMENT: NBC Slow shoulder, slow lane and middle lane – 4,5km SBC Slow shoulder and slow lane - 4,6km Thickness 190 to 220mm Area 75 000m² Volume 16 000m³ Reinforcement 720tonnes

70. MILLING:12 000m³ ASPHALT:NBC Fast lane and fast shoulder - 7,0km SBC Middle lane, fast lane and fast shoulder - 6,3km Bedding (below concrete) 6 200tonnes Base and Levelling 17 500tonnes SMA Surfacing 108 000m² DRAINS:Concrete for Side Drains 3 560m³ Mass concrete (Make up) 600m³ CONCRETE BARRIERS: 6,8km

71. GENERAL VIEWS

77. ACCOMMODATION OF TRAFFIC

92. CONCRETE PAVEMENT

120. EVAPORATION RATE DIAGRAM

121. CONCRETE RESULTS FORM

122. PROFILOGRAPH

125. PROFILOGRAPH EQUATION

126. PROFILOGRAPH RESULTS

127. IN SITU MILLING