Title: Laboratory test method for the prediction of the evolution of road skidresistance with traffic
1Laboratory test method for the predictionof the
evolution of road skid-resistance with traffic
- Minh-Tan Do
- LCPC
- Research engineer
- E-mail minh-tan.do_at_lcpc.fr
2Scope
- Need to predict skid-resistance evolution
- Existing empirical tools
- LCPC polishing tests
- From laboratory simulation to road prediction
- Conclusions
3Need to predict skid-resistance evolution
- Road skid-resistance evolves with time
- due to mechanical actions (traffic)
- due to climate effects
- Prediction of skid-resistance evolution is
needed - to forecast road maintenance
- to ensure long-term performance
- to optimize material choice
4Existing empirical tools
- Experimental sites tracked over time
- drawbacks costs ?, time ?
5LCPC polishing tests Objectives
- Quick laboratory tests
- Able to test concrete-asphalt mixes and
aggregates - Comparable results with road data
- Means to predict skid-resistance evolution
6LCPC polishing tests Test machine
7LCPC polishing tests Wehner/Schulze machine
8LCPC polishing tests Specimens
- Concrete asphalt
- Cores taken from pavements or laboratory-made
slabs - Aggregates
- Mosaic discs (fraction 7.2/10 mm)
9LCPC polishing tests Test procedure
- Friction-time plot
- Friction measurement every 1000 passes ? µmax is
reached - Next stops 3-5-9.104 passes
- End 180,000 passes
10LCPC polishing tests Laboratory results (1/2)
- Aggregates vs asphalt mixes
11LCPC polishing tests Laboratory results (2/2)
µWS 1.06(PSV/100) 0.20
12From laboratory to road
- Core sampling on new roads tracked over time
Wheel paths
13From laboratory to road
- Core sampling on circulated roads
Wheel paths
14From laboratory to road
- Relationship polishing duration traffic
15From laboratory to road
- Simulation vs actual evolution
16From laboratory to road
- Towards a prediction of skid-resistance
evolution - Problem statement
17From laboratory to road
- Towards a prediction of skid-resistance
evolution - Approach
18From laboratory to road
- Towards a prediction of skid-resistance
evolution - Relationship µWS LFC/SFC (source from Huschek,
2004)
19From laboratory to road
- Towards a prediction of skid-resistance
evolution - Comparison prediction/measurement
actual LFC-T plot
µWS-N plot converted into equivalent LFC-T plot
20Conclusions Where are we / objectives?
- Quick laboratory tests
- ½ day to plot a full friction-time curve, could
be ? depending (N 0.024T) on anticipated
traffic - Able to test concrete-asphalt mixes and
aggregates - Yes, except very aggressive surfaces
- Comparable results with road data
- Yes, first tendencies to be supported by other
experiments - Means to predict skid-resistance evolution
- Promising first results
21Conclusions Next step
- Investigate the relationship polishing duration
? traffic - k (N kT) should be constant ?
- Relationship µWS ? LFC/SFC
- Relative influences light vehicles/trucks
- Prediction model, taking into account other
mechanisms (seasonal variations, ageing)