Gravel Road Maintenance Issues & Sustainable Solutions Jointly prepared by David Edge - Roading Manager, Hurunui District Council Ken Avant - Road Projects Engineer, Waimakariri District Council Carl Grabowski - Senior Transportation Engineer, MWH
Gravel Road Maintenance Issues & Sustainable Solutions
Introduction •
Management & Budgetary Constraints
•
Ratepayer, Road-user & Council Expectations
•
Levels of Service
•
Alternatives to Long-term Maintenance
•
Reliable “good old” Methods & Innovative Alternatives
•
Optional Sustainable Options
•
Questions
Gravel Road Maintenance Issues & Sustainable Solutions
Management & Budgetary Constraints • Sealing Roads = favoured option for Road Users & Councils (comfort, lower maintenance, etc). • Although maintenance costs can be relatively high, LV Roads do not easily qualify for Seal Extension funding. • Councils / Contractors constantly searching for methods to reduce maintenance needs. • ‘Crab Bucket Syndrome’ & sharing of cross-boundary efficiencies. • Sustainable roading research & workshops.
Gravel Road Maintenance Issues & Sustainable Solutions
Ratepayer, Road-user & Council Expectations Ratepayer
Road-user
Council
Relatively smooth - no Minimum corrugations & corrugations / potholes, potholes - road user minimum ‘flying’ gravel. comfort, safety & traction.
Meet contractual specification, prompt & effective response.
Minimum dust nuisance (inhalation & household effects).
Minimum dust nuisance (visibility & vehicle effects).
Well bound running course, cost-effective dust suppressants, low environmental impacts.
Use of the shoulder / verge (landscaping, parking, etc).
Verge scrub-free / well maintained to improve visibility, emergency / rest stopping.
Contractual compliance (environmental mtce, shape, drainage, max road width maintained.
Stormwater mgmt within road corridor.
No ponding, rutting, rilling, potholing, aquaplaning.
Contractual drainage compliance - safety, asset maintenance & environmental.
Gravel Road Maintenance Issues & Sustainable Solutions
Typical examples of rural heavies causing major damage to our unsealed roads:
Gravel Road Maintenance Issues & Sustainable Solutions
Levels of Service
Gravel Road Maintenance Issues & Sustainable Solutions
Contract Issues • Clear wording in documents • ‘Total Management Systems’ • Good grader regimes • Maintenance Contractors buy-in & investment • Partnering agreements to share benefits / losses • “Kaizen” Continuous improvement - not just BAU
Gravel Road Maintenance Issues & Sustainable Solutions
Alternatives to Long-term Maintenance
Gravel Road Maintenance Issues & Sustainable Solutions
Foamed Bitumen stabilization of an unsealed road Kennedys Hill Road, Waimakariri District • Steep, windy section • Layer thickness / fines • Drainage issues • Further maintenance • Ongoing monitoring
Gravel Road Maintenance Issues & Sustainable Solutions
• Good finish • Cracking • Drainage • Surplus material • Some potholes • Maintenance
Gravel Road Maintenance Issues & Sustainable Solutions
Otta Seals - Local & International Practice • Single chip seal with prime & binder (13.2mm) thickness = ALD (8 - 10mm) • Single Otta seal with binder & graded aggregate (no prime) thickness = minimum 16mm • Double Otta seal with binder & graded aggregate (no prime) thickness = minimum 32mm
Gravel Road Maintenance Issues & Sustainable Solutions Type
Additional
Application
Expected life (Years)
Temp. seals & maint. reseals
5 - 6 (dependant on surfacing type & quality)
Single Otta seal
No sand cover
Single Otta seal with sand cover
Fine sand in the AADT ≤ 500 sand cover
9 - 11
Crusher dust or river sand in the sand cover
10 - 12
Double Otta seal
AADT > 500
12 - 15
Detailed info available in comprehensive guideline produced by the Norwegian Public Roads Administration (1999)
“A Guide to the Use of Otta Seals”
Gravel Road Maintenance Issues & Sustainable Solutions
Fulton Hogan have done several trials Mayes Rd, HDC (Nov. 2004) • AADT ≤ 500 • Unsuitable materials • Good finish & drainage • ‘Life Cycle’ cost benefits • No maintenance
• Keddell Road, Central Otago DC • Mayes Road, Hurunui DC • Church Road, Dunedin CC • Sinclair Road, Southland DC • Peroa Road, Gisborne DC
Gravel Road Maintenance Issues & Sustainable Solutions
Otta Seal - Proposed Bramleys Road application (WDC) Issues • Dust nuisance • Rutting & potholes • Drainage
Choice Influences • Regular complaints • Good structure / shape • Low volume (117/day) • Drainage - minor work
Gravel Road Maintenance Issues & Sustainable Solutions
Otta Seal - International Practice
International • Norway / Sweden / Iceland • Kenya / Botswana / Zimbabwe / SA • Bangladesh / Australia
Gravel Road Maintenance Issues & Sustainable Solutions
Otta Seal - International Practice (a)
(c)
(b)
Single Otta seal with sand cover seal in Botswana “beds down” after a few months in service (a) and (b), and still looks good after 9 years in service (c).
Gravel Road Maintenance Issues & Sustainable Solutions
Otta Seal - International Practice (a)
(b)
(c)
Single Otta seal in Bangladesh aggregate spread by hand (a), compacted with loaded trucks (b), “beds down” and looks good after 2 years in service (c).
Gravel Road Maintenance Issues & Sustainable Solutions
Otta Seal - International Practice
(a)
(c)
(b)
(d)
Otta seals in Kenya (a) and (b) and South Africa (c) and (d) using natural quartzitic and laterite aggregates.
Gravel Road Maintenance Issues & Sustainable Solutions
Reliable “good old” Methods & Innovative Alternatives
Gravel Road Maintenance Issues & Sustainable Solutions
Issues with reliable “good old” methods
• • • •
‘Smoothing’ vs. Rip & Reshape TTM during maintenance operations Heavy vehicles & gravel loss Raised shoulder syndrome
Gravel Road Maintenance Issues & Sustainable Solutions
Innovative Alternatives Overgrown shoulder - reclaiming road width • Consider landowner concerns - metal-wash, mowing, etc. • Tractor mounted shoulder trimming - soil / vegetation build-up on shoulder trimmed back to regain metal width (Killiner Contracting, NZ)
Gravel Road Maintenance Issues & Sustainable Solutions
Raised shoulder syndrome Tractor or grader mounted shoulder reclaimer available to eliminate soil / gravel build-up on shoulder - loosened and swept off or re-used. “All American Disk” - Doyle Inc, Minnesota, USA “Tiger Claw” - Agriquip Ltd, New Plymouth, NZ Killiner Contracting, NZ
Gravel Road Maintenance Issues & Sustainable Solutions
Shoulder reclaiming available locally (Killiner Contracting, NZ) • Trialed in various N-Island districts • Potential for minimum 20km/day (both sides) @ approx. $0.05/m • Reclaims between 50 - 100m3 material (mostly metal) / side / km • TLA’s in USA - annual cycle in maintenance contracts
Gravel Road Maintenance Issues & Sustainable Solutions
Pneumatic (tyred) roller mounted on rear of grader (locally available - Walk ‘n’ Roll International Ltd, Auckland) and various blade attachment options (used by Sicon / SDC) can make rural road maintenance a little easier.
Gravel Road Maintenance Issues & Sustainable Solutions
Towed machinery used in USA to pulverize gravel and sod windrows into re-usable material on unsealed roads.
Gravel Road Maintenance Issues & Sustainable Solutions
Optional Sustainable Solutions Cost / benefit comparison of options being investigated as alternatives to Grader maintenance •
Reclaimed metal + Ballast + Cement stabilisation
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Reclaimed metal + Otta seal
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Re-metalling + Otta seal
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Stabilisation (Cement / FB) + Seal (Otta / Chip)
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AWT (Full reconstruction + Chip seal)
Gravel Road Maintenance Issues & Sustainable Solutions
Useful References / Acknowledgements •
“A Guide to the Use of Otta Seals” - Norwegian Public Roads Administration
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“Tractor-Mounted Shoulder Reclaimer - Works Well and Saves Money” US Roads, Road Management Journal
•
“A Ditch in Time” - Rural Home Technologies, Road/Driveway Maintenance
•
“Gravel Roads: Maintenance & Design Manual - Section V: Innovations” US Environmental Protection Agency
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“Unsealed Roads are Sustainable” - 1997 IPENZ Conference (Alan Ferry)
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“Replacing Waste Oil as a Dust Minimisation Technique” - Jeff Waters (FH) 2007 LV Roads W/shop Presentation
•
“The All American Disk” - Doyle Inc. (video clip on Google / YouTube)
•
“Tiger Claw” marketing material supplied by Richard Capper, Agriquip
Gravel Road Maintenance Issues & Sustainable Solutions
Questions?
Thank You
