OLD CONCRETE MAKES WAY FOR NEW ASPHALT A Laatz, N Cocks, N Burger

1 INTRODUCTION CAPE TOWN CONGESTION ALMOST WORST IN SOUTH AFRICA NATIONAL ROUTE 2, CAPE TOWN INTERNATIONAL AIRPORT, BORCHERDS QUARRY INTERCHANGE – TRANSPORT HUB PROJECT – FIRST STAGE OF CONGESTION ALLEVIATION

First Impression for Visitors to Cape Town Project Area First Impression for Visitors to Cape Town

1 INTRODUCTION cont RE-CYCLING - DOWN-CYCLING OF CONCRETE AND ASPHALT MATERIALS CONSTRUCTION OF NEW ASPHALT BASED PAVEMENT LESSONS LEARNED

2 PROJECT BACKGROUND CONCRETE PAVEMENT 1970’s – AGGREGATE SULPHATE REACTION ASR/AAR MAINTENANCE WITH JOINT REPAIRS AND ASPHALT SEALING LAYERS

Background Old Jointed Concrete Pavement from mid 70’s exhibited distress related to ASR/AAR - Repaired Joints and Re-Sealed

Background Concrete Paving Train

Concrete Slip-Form Paver Background Concrete Slip-Form Paver

Handwork Edge Finishing Background Handwork Edge Finishing

Application of Curing Compound Background Application of Curing Compound

Revealing the Past Repaired Joints and Sealed with SAMI and bitumen rubber asphalt overlay

2 PROJECT BACKGROUND cont IMPROVE AND UPGRADE TRANSPORT HUB FOR PRESENT CONGESTION AND FUTURE DESIGN – ECONOMICS – RISK MITIGATION DESIGN - STAYING GREEN – RE-CYCLING - DOWN- CYCLING

3 PROJECT DESIGN TRANSPORT PLANNING – MEDIAN LANE PAVEMENT DESIGN - ALTERNATIVES MATERIALS DESIGN – CONCRETE / RAP BLEND AND ASPHALT LAYERS STRUCTURES DESIGN – PRESENT AND FUTURE

Median Lane Design Layer TRH14 Thickness Description UTFC 24 mm Friction Course 14mm stone - A-E2 AC 40 mm Dense Asphalt Surfacing – A-E2 BC 90 mm Dense Asphalt base – A-P1 Subbase 250 mm Subbase, 2 Layers of 125mm commercial stone stabilised with 3% cement. SSG 150 mm Selected Layer Commercial stone Subgrade Road Bed in-situ sandy material

Existing Reconstruction Layer TRH14 Thickness Description UTFC 24 mm Friction Course with 14mm stone – A-E2 AC 40 mm Dense Asphalt Surfacing – A-E2 BC 120/90 mm Dense Asphalt Base – A-P1 (2/1 lifts) Subbase 400/300 mm Subbase, layer 1 – 200/150 in-situ, layer 2 - 200/150mm reclaimed concrete and RAP blend, all stabilised with 3% cement. SSG    (Local Pioneering) 200 mm    300 mm Middle lane unstabilised in-situ, slow lane 3% cement stabilised acting as mole barrier. 200mm diameter dump rock and geotextile

4 CONSTRUCTION CONSTRUCTION PHASING GROUND WATER LOCAL EMPLOYMENT

Construction Phasing

Dealing with Water

Pioneering

Layerworks

Local Employment

4 CONSTRUCTION cont RECLAIMING ASPHALT RECLAIMING CONCRETE OFF-SITE CRUSHING AND BLENDING ON-SITE PROCESSING

Reclaiming Asphalt

Reclaiming Concrete

Lifted and Loosened

Pulverizing for Transport

Off-Site Crushing

Processing Green Blend

Compacting Green Blend

4 CONSTRUCTION cont BRIDGE WIDENING PLANNING FOR FUTURE INTERCHANGE

Precast Beams (BQ Bridge)

Piling for Future Interchange

Pile Caps & Dewatering

4 CONSTRUCTION cont LARGE STONE ASPHALT BASE - A-P1 ASPHALT WEARING COURSE - A-E2 ULTRA THIN FRICTION COURSE - A-E2

Asphalt Base Trial Section

Asphalt Surfacing

Asphalt Friction Course

5 LESSONS LEARNED ECONOMIC BENEFITS – BROADER ENVIRONMENT GRADING MODULUS AND WORKABILITY GRADING COMPLIANCE GOING GREEN USING SPOIL AND MAINTAINING STANDARDS

Aircraft View

Birds Eye View

Road User View