Operations Department Road Rehabilitation
Information Session
City of Prince George Statistics Population
75,828 (2011)
Area Within City Limits
32,040 Ha (123.7 sq.mi.)
Length of Paved Roads
580 km
Length of Gravel Roads
90 km
Length of Sidewalks
184 km
City Bridges / Structures 11
Transportation Hand Outs 2007 – 2011 Capital Road Paving Projects Map Includes Road Resurfacing & enhanced Paving 2012 Transportation Capital Projects Map Road Resurfacing
Micro Surfacing is a polymer modified cold mix paving system that is a mixture of dense graded aggregate, asphalt emulsion, water and mineral fillers; will provide a new traveling surface, typically placed on lifts of 9.5mm; does not add to road structure only protects existing asphalt surface (prolongs life of asphalt); Micro Surfacing did not perform well on high speed, high volume, deteriorating road (Ospika), but did perform well on a residential street (Nation Crescent).
Cost for Micro Surfacing is $7.00 to $8.00 per square metre Pros Cost effective Life expectancy 5 to 7 years Open to use after a few hours
Cons Surface repair only Does not repair reflective cracking, failed asphalt or potholes. Locally has not performed well on high speed, high volume roads.
May be used to repair wheel ruts Improves skid resistance May be applied in thin lifts (9.5mm) Protects original pavement surface
Nation Crescent - 2005
Thin Lift Overlay is a 40 to 50mm lift of asphalt placed on existing road with limited remedial work done prior to the new lift being placed; work done prior to overlaying would consist of pothole patching and filling of any major cracks within the road surface; adds strength to the existing road structure, but reflective cracking will likely appear through the new lift of asphalt within a couple of years; candidates for Thin Lift Overlays are roads with good road structure, with only a few minor surface deficiencies, and roads that were left low when constructed; The enhanced patching program generally uses this procedure.
Cost for Thin Lift Overlay is $22.00 per square metre Pros
Cons
Reasonably cost effective
Existing defects may show on new surface
Allows to re-establish road crown Removes minor wheel ruts Adds to road structure Life expectancy 12-15 years
Does not repair heaves or bumps Some roads may require curb relief milling Does not address sub-base problems
Johnson Street - 2011
Mill and Overlay removes 50mm of the old asphalt surface and replaces it with new; milling will remove surface cracks, wheel ruts and minor potholes (less than 50mm deep) and allow the final road elevation not to change which is beneficial for roads with curb and gutter; Candidates for Mill and Overlay projects are roads with a failing asphalt surface, but a good road structure. Cost for Mill and Overlay is $28.00 per square metre
Pros
Cons
Cost effective
Asphalt surface repair only
Allows to re-establish road crown
Timing – milling contractor availability
Removes surface deficiencies
Does not address sub-base problems
Does change road elevation (curb reveal)
Milled materials are used to surface gravel roads
Ospika Boulevard - 2011
Pulverize and Pave is the pulverizing of the asphalt and granular base course, compacting and then overlaying with a 50mm lift of crush and a 75mm lift of asphalt; pulverizing can be to a depth of up to 300mm,although most roads only require 150mm depth to capture the existing road base material and the asphalt surface, so all surface distresses can be removed and the road asphalt surface and granular base course will be new while adding to the overall road structure; candidates for Pulverize and Pave projects are roads with major surface deficiencies (cracking, rutting, and potholes), but a good road structure. Cost for Pulverize and Pave is $38.00 per square metre
Pros
Cons
Repairs all surface deficiencies, such as cracking, raveling and potholes Allows for re-profiling and minor widening
Isolated sub-base failures may have to be repaired prior to construction Not ideal for roads with curb and gutter
Life expectancy 15 years Adds structural strengths
Old Summit Lake Road - 2011
Full Reconstruction is the removal of existing surface and all granular materials to competent sub-grade elevation as determined by a Geotechnical Engineer;
rebuild the road structure based on a Geotechnical report; we consider this the most labour intensive and costly method for rehabilitating roads that were originally constructed with minimal gravel sub-base and poor sub-grade; cost for Full Reconstruction varies widely depending on: curb and gutter versus ditches, depth of excavation to suitable sub-grade, amount of landscaping etc.
Cost for Full Reconstruction is estimated between $97.00 and $160.00 per square metre Pros
Cons
Completely new road structure
Very expensive
Ability to change profile, grades, width and drainage
Time and disruption
Life expectancy 15 to 20 years
Usually done on low volume traffic roads
North Blackburn Road - 2007
Hot in Place Asphalt Recycling is the process where the current asphalt surface is heated, scarified, mixed with new asphalt (typically 15%) and placed as a new surface; candidates for Hot in Place Recycling are roads with surface problems only. Cost for Hot in Place Asphalt Recycling can be expected around $13.00 per square metre Pros
Cons
Cost effective if done in large amounts
Small projects may not draw interest from contractors
Allows to reestablish crown and road shape
Does not repair sub-base of sub-grade failures
Approximately 15% new material
Difficult to do on roads with manholes and valves
Ospika Boulevard - 2003
Seal Coat is the process where the existing road surface (gravel or asphalt) is sprayed with emulsified asphalt cement then covered with aggregate; seal coat provides a waterproof membrane that allows the road surface to shed water preventing it from entering the base material and it also improves skid resistance; best suited for roads with low traffic volumes; seal coat may be applied in single or double seal applications depending on current road condition; candidates for Seal Coat are gravel roads with good structure and low volume asphalt roads with minor surface distresses. Cost for Seal Coat at single seal application can be expected to be $3.50 per square metre and for double seal application $5.00 per square metre.
Pros
Cons
Protects road structure from water
Final surface is not smooth
Improves skid resistance
Does not repair potholes, rutting etc.
Dust control on gravel roads Low initial costs in comparison to thin asphalt overlays
Surface treatment only No local contractors do this type of work
Example of Seal Coat
Foamed Asphalt
foamed asphalt base stabilization is a roadway recycling process in which all of the pavement and some of the underlying material is pulverized and treated with a foamed additive to produce an improved, stabilized base; thin layer of granular material is applied to the road surface to establish final grade and road crown; a layer of hot mix asphalt is applied. Cost for Foamed Asphalt can be expected around $55.00 per square metre Pros
Cons
Removes all asphalt distresses
Not many contractors do this type of work
Increases road structure & strength
Contractor timing & availability Not suitable for roads with curb & gutter or underground utilities Increases road elevation
Minimal traffic disruption
Cranbrook Hill Road - 2008
Interlocking Concrete Paver Surface Pavers are made of cementitious materials in a quality controlled environment and can be manufactured to be capable of resisting a high degree of freeze-thaw cycles and deicing salts; provides character/decoration to the travelling surface; in most cases requires the removal of existing surface and base granular; requires quality control on the bedding materials and joint sand specifications. Cost for Interlocking Paver Stone Roadway $100.00 to $120.00 per square metre
Pros
Cons
Life expectancy is 25+ years Ease of Installation, does not require substantial equipment to place No pot holing due to the ease of maintenance Variety of colors or laying patterns available, (herringbone recommended for driving surface) Provides traffic calming effect Can be utilized for bridge surfaces
Initial cost is high
George Street - 2011
Asphalt Road Surfacing Options Summary In the 2007 Capital Road Rehabilitation Program the City of Prince George used the Mill and Overlay option twice, the Full Reconstruction method three times, a form of the Pulverize and Pave once, and a procedure similar to the Thin Lift Overlay once. The finished product of all methods used has been good. The Full Reconstruction projects have exceeded the original budget estimates due to varying unforeseen conditions. The Mill and Overlay, Pulverize and Pave, and Asphalt Overlay methods all came in under the original estimates. With the desire to achieve a new asphalt surface on more lane kilometers it should be considered to move away from Full Reconstruction projects and proceed with more cost effective methods for resurfacing our roads. Some projects will require Full Reconstruction, but we should address the localized areas within the project for Full Reconstruction and utilize a more economical method for the areas of the project that are okay. The existing road conditions will always dictate the best suited methodology for repair, but to get the most out of our dollars it would be best to consider Mill and Overlay, Thin Lift Overlay, and Pulverize and Pave as the core of our Capital Road Rehabilitation Program. The other methods have a place in our Capital Road Rehabilitation Program and should always be considered as an option.
Pothole Patching Options
Explanation provided by the Michigan Department of Transportation
Pothole Patching Options Spray Patching Has been utilized on sections of Domano, Ospika & Massey with marginal results. Pros Cons One person No local contractors operation Marginal performance Initial cost of unit
Cold Asphalt Patch Other similar products are solicited annually by various suppliers Pros Cons Cost - $685/tonne + Easy application shipping Performs in most No local availability conditions
Typical Pothole Patching To run 2 shifts, it costs approximately $14,600 per week
Typical Full Size Patch Crew
Major Pothole Patching Ospika Blvd between 22nd Ave and Ferry Ave
Capital & Enhanced Paving Program Cost Breakdown 2004 - 2011 4,000,000 3,500,000 3,000,000
2,500,000
Contracted Other 2,000,000
Contracted Paving
City
1,500,000 1,000,000 500,000
2011
2010
2009
2008
2007
2006
2005
2004
-
Capital & Enhanced Paving Program Cost Breakdown 2004 - 2011 Pothole Statistics Date Range Specific January 1 to May 25
4,000,000 3,500,000 3,000,000
14,000.00 12,000.00
Axis Title
2,500,000 2,000,000
10,000.00
Contracted Other
8,000.00
Contracted Paving 6,000.00
1,500,000 1,000,000
City
4,000.00 2,000.00 0.00
4,546.00
10,038.00
Cracks Metres
1,502.25
386.00
1,471.35
459.50
312.75
2,378.00
2005
2004
-Overlays m2
2011
13,522.00
2010
# of Hot Potholes
500,000
2009
2012 1,517.00
2008
2011 665.00
2007
2010 3,259.00
2006
# of Cold Potholes
Capital & Enhanced Paving Program Cost Breakdown 2004 - 2011 4,000,000
Asphalt Cost Comparison Cost per Tonne
3,500,000 3,000,000
2010
2011
$143.00
$143.00
2012
2,500,000
Prince George
2,000,000
Contracted Other $147.50 Contracted Paving
Okanagan 1,500,000 (Average of 3 Municipalities) 1,000,000
32.0% Less 29.5% Less
500,000
2011
2010
2009
2008
2007
2006
-
2005
30.4% Less
Comparable Comparable 18.9% Less to PG to PG
Vancouver Island
2004
City
Capital & Enhanced Paving Program Cost Breakdown 2004 - 2011
4,000,000
Roads Sidewalks and Bridges Challenges
3,500,000
• Road Rehab funding at $3.5M is ~ 50% of the 3,000,000 desired funding level to maintain current service levels. 2,500,000 Contracted Other
• The effects of inflation on road rehab costs Contracted Paving (~14%/yr for materials) far exceed the consumer City 1,500,000 price index. 2,000,000
1,000,000
• There is limited and inconsistent funding for 500,000 sidewalk maintenance, rehab. and new linkages. 2011
2010
2009
2008
2007
2006
2005
2004
• Foothills Bridge strengthening has been deferred.