Accelerated Pavement Testing in Southern Africa · Update of SAPMDM and THR4: 1996 - Theyse Development of 3D stress sensor and laser profilometer: 1996 – 1997 Delivery of a HVS

© Hyder Consulting Pty Ltd

AAPA Workshop – 16-Oct-2009

Accelerated Pavement Testing in Southern Africa

Pablo Balmaceda

© Hyder Consulting Pty Ltd 2

Contents

IntroductionHeavy Vehicle Simulator (HVS)Mobile Load Simulators (MLS and MMLS)ConclusionsRecommendations


Introduction

APT – Controlled loading to simulate long term in-service loading conditionsAccelerated accumulation of damageControlled testing environmentStarted with AASHTO road testThree types: full scale mobile, full scale fixed, and mobile Simulation of many years of traffic within weeks or months


Introduction

APT in South AfricaFirst HVS prototype: 1968Initiation of HVS programme with 3 HVS units: 1978Development of Multi-depth Deflectometer: 1980First TRH4 Guideline: 1980First draft of SAMDM: 1980 – Freeme, Maree, PattersonTesting on road and airport pavements: granular layers, GEMS, cemented layers, LAMBS: 1980 - 1993Development of temperature control chamber and new data acquisition system for HVS: 1993 – 1994


IntroductionAPT in South Africa (continued)

HVS testing on Caltrans Trial Sections in SA after sell of two units to Caltrans: 1994HVS testing on superlight pavements, porous asphalt: 1995Another HVS unit sold to the US Corps of Engineers: 1995Update of SAPMDM and THR4: 1996 - TheyseDevelopment of 3D stress sensor and laser profilometer: 1996 – 1997Delivery of a HVS units to RRL in Finland and Sweden: 1997Testing on various pavements types including LI built ones


IntroductionAPT in South Africa (continued)

Transfer functions developed for thin asphalt, thick asphalt (fatigue), granular (shear failure), cemented (fatigue and crushing), subgrade (permanent deformation), GEMS (shear failure), ETB (shear or fatigue), Foam Bitumen modified bases (shear of fatigue), UTCRCP.


HVS - GeneralOriginally developed in 1968More than 500 test sectionsHydraulically operated loading assembly carrying single/dual wheelWheel Loads from 20 to 100 kN at 14 km/h and 200 kN for airport pavements (Bigfoot)Track with: 1.5 m, track length: 8 mHVS test facilities in California, Florida, CRREL, Sweden-Finland

http://www.gautrans-hvs.co.za/


HVS - Monitoring and Instrumentation

HVS laser profiler RSD MDDPressure and strain transducersCAM

Stress in Motion MeterTermocouplesTrenchingData Capture and StorageThe DatabaseDCP


HVS – Monitoring and Instrumentation

Multi-depth Deflectometer (MDD)

Laser Profilometer

Road Surface Deflectometer (RSD)

Termocouples


HVS – Monitoring and Instrumentation

Stress-in-Motion (SIM)

Crack Activity Meter (CAM)Dynamic Cone Penetrometer (DCP)

Crack Monitoring

Trenching


Full Scale Mobile Load Simulator (MLS 10)

Established in 1998 by MLS Test Systems in Stellenbosch 20 APT research projects since 1998MLS10: 3m x 3m x 2.4m frame4 wheel bogies at 26 km/h, 7200 axle loads/hour - UnidirectionalHydraulically operatedIN 2004, APT in Mozambique





MLS 10 Testing at Manhica Test Sections

A closer view at MLS 10 Testing at Manhica Test Sections



Test Sections in Manhica, Mozambique, 2006


Model Mobile Load Simulator (MMLS 3)

Standarized field and laboratory set-ups Tests in dry heated or wet heated modes4 bogies, 1 axle/bogie, 1 wheel/axleMaximum tracking with: 80 mmLoad/wheel: 1900 @ 560kPa or 2700 @ 800 kPa. So loads are scales but real tyre pressures7,200 load applications/hourSuitable to explore performance of upper 125 mm of pavement



WATER BATH

CLAMP SCREW

CLAMP BRIQUETTE LONG. CLAMP

WHEEL RAMP

WATER INLET

DRY OUTLET

WET OUTLET

ADJUSTIBLE WEIR

OVERFLOW TANK

2360

900 DRIVE MOTOR

Φ300 PNEUMATIC TYRE

CRANK FOR HEIGHT SETTING

1260

363

80

Φ300HOT WATER

INLET SUCTION OUTLET

PONDED WATER

LONGITUDINAL SECTION CROSS SECTION



SMA specimens after MMLS testing in the laboratory for King ShakaInternational Airport, Durban

Field MMLS testing on SMA at King Shaka International Airport, Durban


Conclusions

Numerous Technical Developments and Design Guidelines for a large array of pavement materials: subgrade, asphalt, granular (crushed stone, gravel, sands), CTB, ETB, GEMS, FBMB, UTCRCP in various pavement configurations, compaction ranges and environmental conditions.Overlay thickness designsInput on construction practices and specificationsInput on pavement materials mix designs and testingInput on quality control by better defining correlations between HVS tests and laboratory indicator testsSubstantial economic benefits from APT implementation


Recommendations

APT in Australia highly advisable:• To monitor different asphalt mixes: dense graded, open

graded, polymer modified, bitumen-rubber modified, warm asphalt techniques

• To monitor type and density of granular layers: Proctor versus Mod. AASHTO

• To assess modification / stabilization of granular materials: mechanical and with cementitious, bitumen emulsion, foam bitumen binders

• To determine pavement depth• To assess and, if required, amend construction

techniques and specifications


Recommendations

APT in Australia highly advisable (continued):• To minimize risk in implementing new technologes /

materials• Maximize the implementation of new technologies or

optimization of current technologies to avoid under- or over-designs.

Understand that the perceived high APT cost will result in substantial savings in pavement construction / maintenance and road user costs

Documents

Accelerated Pavement Testing in Southern Africa · Update of SAPMDM and THR4: 1996 - Theyse Development of 3D stress sensor and laser profilometer: 1996 – 1997 Delivery of a HVS