Aspects of Current MLS APT Activities in southern Africa

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Aspects of Current MLS APT Activities in southern
Africa

• Fred Hugo
• Road Pavement Forum
• 7 November 2006

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Applications of MLS technology

• ITT - Univ of Stellenbosch
• Evaluation of Proprietary Cold mixes
• Development of new design approach for the ANE in
  Mozambique MLS10 and MMLS3
• SRT laboratory KZN
• Evaluation of HMA performance on airports and
  highways
• Local evaluation of design mixes prior to paving
  (field and lab)
• Roadlab
• Local evaluation of design mixes prior to paving
• Participation in research project of GDPWT in
  conjunction with the HVS
• See www.sun.ac.za/mls

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Applications of MLS technology

• ITT - Univ of Stellenbosch
• Cold mixes
• Development of new design approach for the ANE in
  Mozambique MLS10 and MMLS3
• SRT laboratory KZN
• Evaluation of HMA for application on airports
  and highways nationally and internationally
• Evaluation of factors affecting mix performance
• Roadlab laboratory Gauteng
• Evaluation of design and construction of mixes
  for consultants contractors and authorities
• Participation in research project of GPWTD in
  conjunction with the HVS
• See www.sun.ac.za/mls

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ITT University of Stellenbosch

• Testing of Cold Mixes
• Evaluate performance of five proprietary cold
  asphalt mixes available in South Africa
• tested to evaluate rutting performance and
• susceptibility to moisture damage
• Laboratory characterisation supplementary

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SRT commercial laboratory

• Testing of
• Binders
• Different materials
• Different mix types
• National roads
• Wide range of airports
• Specimens transferred across countries and
  continents SA, Africa, Australia, Dubai
• Higher temperatures
• Varying speeds

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Roadlab commercial laboratory

• Testing of
• UTFC to evaluate influence of flakiness
• Comparison of lab design mix performance to field
  mix performance.
• Scheduled to do testing in conjunction with the
  CSIR - HVS to evaluate asphalt surface layers
• Factors include among other
• Layer thickness
• Contact stress
• Temperatures
• Varying speeds
• Aging

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Evaluation of Long-Term Behaviour of Pavement
Layered Materials by means of APT and
Supplementation/Verification Testing in Mozambique

• With permission of
• Administraçao Nacional de Estradas (ANE)
• Contract 206/CON/ES/DEN/2003
• The University of Texas MLS Mozambique JV

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Location Stellenbosch and Mozambique
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Pavement Composition
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Mozambican Pavement Structure Actual
Performance
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Project Background

• ANE embarked on an APT program as most cost
  effective means to
• Evaluate construction techniques
• Determine most economical use of available
  sub-standard materials
• Develop a mechanistic-empirical design system
  best suited for its needs with due regard to
  materials and environment

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MMLS3

• MOBILE MODEL LOAD SIMULATOR

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Third Scale Construction in Laboratory
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Construction
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Laboratory Test Conditioning

• Hot air used for heating surface to 55 C
• Recirculated water on surface at 20 C
• Trafficking alternated between 200 000 heated
  load
• applications and 50 000 wet load applications
• Protocol selected to simulate critical field
• conditions

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Distress Development
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MLS10

• ROAD TESTER
• FULL SCALE PAVEMENT TESTING

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Construction of Full Scale Test Sections
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MLS10 in laboratory in Stellenbosch during shake
down testing
Pre-commission Testing Stellenbosch University
March/April 2006
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MLS10 VIDEO
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MLS10 Characteristics

• Max speed 26 k/h
• Max no. of load applications per hour 7,200
• Wheel load - half axles
• 4 ton 7.5 ton (max) on duals
• 5,5 ton on Super single wheels.
• Wheel size, tire type/pressure
• 295/60 R22.5 and
• Super single 385/65.
• Continental Rated _at_ 850 kPa pressure testing up
  to 1,000 kPa

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MLS10 testing on site Manhiça Mozambique
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Wheel Path on Pavement
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Surface Damage Cracking and Pumping
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Rut Accumulation
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Distress monitoring via P SPA
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Diagnostic Removal of Trafficked CTB Slab
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Extracted fractured pavement - confirming
manifestation of distress
1.5m
Plan view
400mm
Section
150mm
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MMLS3 and MLS10 proving to be APT tools for
evaluating pavement performance in terms of
shear, interlayer distress, rutting, fatigue and
susceptibilty to moisture damage, in the
laboratory and in the field under different
environmental and age conditions
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QUESTIONS? See www.sun.ac.za/mls