Transcript High PSV on Auckland Motorways

High PSV on Auckland Motorways
Bruce Chappell, AMA
Glynn Holleran, AMA
The Problem
• Central Motorway area 200,000 vpd
• Areas of ramps and mainline require PSV >65
• Mainline requires high texture surfacing for
spray suppression and skid resistance - OGPA
• Default in the past has been to use PSV65
Motouhora aggregate
• Now AMA uses slag in OGPA on mainline
• Slag does not provide PSV to old or new T/10
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
The Problem continued
• For some ramp areas and low speed high
volume SH mainline lanes, T/10 also requires
PSV of high skid resistance surfacing (HSRS).
• But for long term performance HSRS’s rely on
a compatible pavement underneath, i.e.
– structurally sound
– no cracking or differential thermal movement
• Many sites failed to provide long term value
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
The Solution
• For mainline areas use slag in OGPA and
monitor skid performance (SCRIM survey)
• For ramps and low speed areas check crash
history to determine whether slag is an option
• Consider the pavement structure, is it suitable
for HSRS?
• Compare whole of life costs for two options:
– HSRS surfacing with structural fix if required
– Slag aggregates in asphalt and replace more often
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
The Solution continued
• Accept slag option fails T/10 PSV requirement
• Slag option is less than half calcined bauxite
cost (without a structural pavement repair).
• Does HSRS give twice or better the life?
– Not without a compatible pavement (risk)
– Not if poorly constructed (risk)
• AMA proposes to implement best whole of life
option that meets safety requirements.
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
Slag Aggregates
•
•
•
•
•
•
More cubical
High PSV
Consistent
Cost effective
Recycled base material
High Surface friction
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
Properties
• Crushing resistance less than 10% at
230KN (NZ 4407 Test 3.10)
• Weathering Quality Index: 98.2 (NZ 4407)
• Cleanness Value: 95 (NZ 4407)
• Quality Index: AA (NZ 4407)
• LA Abrasion Test: 18% (NZ 4407)
• Wet Dry strength variation: 3 max (NZ
4407)
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
Development Trials
Slag aggregate over 5 years similar
performance to calcined bauxite
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
Browns Road Trial
• British Pendulum Skid (TNZ Test T/2)
• Conventional:
84 -90
• Slag :
94-97
• Calcined Bauxite: 95-98
• PSV
• Calcined bauxite: approx 70
• Slag : 63-65
Now 3 years old- no accidents due to
surface- formerly black spot
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
Grip Testing Browns Rd
Grip Test
Number
Low
New chip
Seal
High
0.6
0.8
Old chip Seal
Conventional
High Skid
0.5
0.6
0.78
1.0
New asphalt
0.5
0.75
0.75
0.95
Slag
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
Hillsborough Road
BPN skid Number
100
80
60
40
Asphalt Base Line
20
0
1
2
3
4
5
6
7
8
9
10
11
Position
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
Grip Tester
Now 2 years old- no accidents
due to surface- formerly black
spot
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
Courtesy New Zealand Steel
Melter Slag In Service Performance:
More Recent Sites – Hawkes Bay
SH5 RP 249/ 3.98 - 4.48 - Slag Site Completed 20/02/2006.
Slag SH5 RP 249/ 3.98 to 4.48
0.7
IL
Average ESC Value per Year
0.6
Natural LHS
0.5
Natural RHS
0.4
Slag LHS
Slag RHS
0.3
0.2
0.1
0
Year
Courtesy New Zealand Steel
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
Melter Slag In Service Performance:
Early Trials
State Hiway 22/Glenbrook Rd. Intersection
Skid Resistance (BPN)
Date
Average (Basalt)
10% ile (Basalt)
Average (Melter Slag)
10% ile (Melter Slag)
8 locations
64 locations
1994
66.5
64.1
66.1
60.0
1995
68.8
67.0
70.5
66.0
1996
48
41.7
62.2
58.0
1997
48.5
44.9
61.8
57.3
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
Courtesy New Zealand Steel
Slag makes good mixes
• SMA used SH20,NGA AMA
• OGPA used NGA and AMA
Tracking Depth
10
9
8
7
6
5
4
3
2
1
0
20000
19000
18000
17000
16000
15000
No of Passes
14000
13000
12000
11000
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
Tracking Depth (mm)
SMA 11 Std
SMA11 PGT64 StS
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
SMA in practice
•
•
•
•
Kirkbride Road
Heavy traffic
Maintains scrim results
Is made with Slag SMA
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage
NZ Transport Agency
Fulton Hogan
Opus International Consultants
Beca Infrastructure
Resolve Group Ltd
Armitage