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TO: |
Mayor and Members of Council |
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FROM: |
Peter
Loukes, Director of Operations and Asset Management |
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PREPARED BY: |
Paul
Ingham, General Manager, Operations |
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DATE OF MEETING: |
2004-Dec-13 |
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SUBJECT: |
Pavement
Management Update for 2004 |
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RECOMMENDATION:
THAT the report titled “PAVEMENT MANAGEMENT UPDATE FOR 2004” be received;
PURPOSE:
This report has been prepared to provide Council with an update of the long-term plan for the maintenance of the Town’s roads. The purpose of the long-term plan is to minimize the cost of road maintenance and improve the overall condition of the network. The previous Pavement Management Update was prepared in September, 2001 followed by a Capital Budget Presentation update in November, 2002.
BACKGROUND:
Like many other GTA
municipalities,
The 2001 Pavement Management Update highlighted the need for the Town to move from a reactionary mode to a proactive mode in terms of asphalt preservation and rehabilitation strategies. The 2001 report also outlined a program of preventative maintenance designed to preserve the aging road inventory and ultimately reduce repair costs at the time of rehabilitation. To provide staff with a consistent and systematic approach to decision making in the application of various strategies, the development of a Pavement Preservation Program (P3) is critical. A P3 consists of decision trees or matrices that municipalities develop to indicate their preferred strategies for specific situations.
Also critical to the success of the preventative maintenance program is the implementation and monitoring of a pavement management system that allows the Town to review the condition of the road inventory at specific intervals and provide recommendations on a proposed rehabilitation program and rehabilitation strategies. The plan is to phase in the pavement management system over the next two years, while at the same time clearing the backlog of roads that will be at or exceeding our thresholds for rehabilitation by the end of 2005. Also critical to the success of any preventative maintenance program is the development of an education and advertising program aimed at customers explaining the goals and objectives of this approach. Without the “buy in” of our customers, the success of this program will be in question. The commitment of top management to this preventative maintenance approach is also a key element to the success of the program.
This report provides 1) an update on the pavement preservation measures employed on Town roads, and 2) an update on the status of the resurfacing plan to clear the current backlog of roads requiring rehabilitation by the end of 2005.
DISCUSSION:
Update On Pavement
Preservation Measures
Two Categories for
Pavement Preservation
Pavement preservation treatments typically fall
into two categories, preventative or corrective. Preventative treatments are designed to seal
the road surface from water infiltration without adding any significant
strength to the road structure and include; slurry seals, micro-surfacing,
crack sealing and hot in-place recycling.
Corrective treatments on the other hand are designed to minimize
reflective cracking by repairing or reinforcing the asphalt base layer. These treatments include the traditional
grind and overlay in addition to asphalt recycling processes such as cold
in-place recycling (CIP) and full depth reclamation with expanded asphalt
stabilization (EA). A brief description
of each treatment is included in the glossary of terms in Attachment 1.
Currently, the primary preventative treatment
employed on Town roads involves crack sealing.
The process of routing and sealing cracks is an effective means of
preventing water infiltration, but this process is typically undertaken on
roadways resurfaced six to ten years earlier.
This means that the pavement structure may have already developed
considerable cracking prior to undertaking the treatment, and that water has
likely already penetrated the surface layer before the sealant is applied. Ideally, this treatment should be undertaken
within three to five years of resurfacing, or following acceptance of new roads
for maintenance at the time of assumption.
The current annual crack sealing capital budget
of $55,000 equates to approximately 45,000 lineal metres of crack sealing. This quantity of crack sealing is not keeping
pace with the growth and aging of the Town’s road network and the program must
be expanded with the full implementation of a preventative maintenance program. It is estimated that the annual crack sealing
budget should be increased to $100,000, equating to approximately 80,000 lineal
metres of crack sealing.
The introduction of a second
preventative treatment is planned for 2005.
Micro-surfacing will be utilized on designated roadways where the Town
will realize continued benefit from preserving the existing asphalt road base
rather than grind and replace the surface layer.
The goal is to increase the money invested in
preventative treatments such as micro-surfacing and target roadways resurfaced
or built ten to fifteen years earlier.
Currently, the bulk of the asphalt resurfacing budget has been
designated for resurfacing roadways exceeding the threshold for asphalt
overlay. As we reduce this backlog and
move to a P3 program, more
resurfacing dollars will be diverted into preservation treatments.
In the first three years of utilizing corrective
treatments such as CIP and EA, we are learning that there are many factors that
can affect the outcome and cost of the treatment. Miller Paving Limited undertook the first of
these projects for the Town in 2002.
Utilizing a combination of equipment known as a recycling train, Miller
completed 2.2km of CIP. The use of a
recycling train was made possible because the roadways being resurfaced were
industrial and had adequate width to accommodate the large equipment. The same year, 5km of EA was also completed
utilizing a combination of pre-pulverizing followed by stabilization and
traditional grading and compacting. We
feel that Miller produced a satisfactory product using this equipment, but the
long term performance of these processes must be monitored for durability and
life cycle.
With the success of these projects, more asphalt
recycling work was tendered in 2003.
Miller Paving Limited was once again the successful bidder for this work
and they utilized specialized equipment from
Since 2002, a total of approximately 27km of roadway
have been rehabilitated utilizing corrective pavement preservation
techniques. Both CIP and EA have been
utilized on various roadways including local, collector and major
collector/industrial roads. We will be
monitoring these roads to determine if they meet our expectations for
durability and longevity.
In summary, we feel that modest overall success has
been achieved to date utilizing the alternative asphalt recycling processes
described above. The environmental
benefits of asphalt recycling over conventional strategies are well documented
and include a reduction in waste and energy consumption. And because these techniques can be completed
quickly, there is less disruption to traffic and neighbourhoods. Although these benefits are difficult to
quantify, they must be weighed against some of the negative aspects of pursuing
alternative strategies as outlined below:
Using the pricing from our current asphalt resurfacing
contract, a cost comparison was conducted between conventional asphalt
strategies versus alternative strategies.
The data in Attachment 2 illustrates that it costs approximately $1.00/m2 more to rehabilitate a roadway using alternative
strategies as opposed to conventional asphalt work. Even though it is more costly to use an
alternative strategy, it is often the most appropriate choice given the
condition of the roadway in question.
This cost often escalates even further due to the existence of unstable
road base conditions as described above.
These unstable road base conditions may be the product of inferior
construction practices at the development stage and/or poor drainage. The unstable conditions only appear after the
work has been initiated during the rehabilitation process and are then
exacerbated by the utilization of extremely heavy equipment and sustained
traffic loading. In most cases where the
chosen strategy involved asphalt recycling, additional costs were incurred by
the Town to reinforce the road base prior to placement of the hot mix
overlay.
The Operations and Asset Management Department will
continue to utilize alternative asphalt strategies where they are deemed most
appropriate for the roadway and conditions in question. To avoid increased costs for road base
stabilization, it is recommended that more money and resources be invested in
pre-engineering studies involving subsurface investigation. This would enable staff to make informed
decisions about the appropriate strategy for a particular roadway. As part of the transition to a preventative
maintenance mode and the introduction of a full P3, the pre-engineering data would form part of the
decision tree or matrices developed to provide staff with a consistent and
systematic approach to decision making.
Also critical to the success of the preventative
maintenance program is the implementation and monitoring of a pavement
management system that allows the Town to review the condition of the road
inventory at specific intervals and provides recommendations on candidate
streets at the threshold for rehabilitation.
The plan is to phase in the pavement management system over the next two
years with the first stage involving the collection of pavement condition
ratings for the entire road network. In
2005, staff will retain a consultant to collect the necessary pavement condition
rating data for utilization in our future pavement management software
(targeted for evaluation and purchase in 2005).
By 2006 we will have a complete strategy for rehabilitation of our road
inventory.
Update On Status Of
Resurfacing Program
The 2001 Pavement Management Update stressed that the
Town would need to invest $3M to $4M a year in 2001 dollars for the next five
years to upgrade the road inventory. In
July 2001, the Town’s road network totalled approximately 751 (two lane)
km. It was estimated that approximately
117 km of this roadway would be at or exceeding our thresholds for
rehabilitation by the end of 2005 (see Table 1 of Attachment 3). Table 2 of Attachment 3 indicates that by the
end of 2004, we will be very close to meeting our yearly projection of
kilometres resurfaced and approximately 34km short of eliminating the original
backlog of 117km. Based on the proposed
2005 Capital Budget of approximately $4,700,000 (excluding GST) for Resurfacing
and Secondary Roadworks, an estimated 26.7km of roads can be accommodated in
2005 at an average cost of $176,000/km.
This leaves a balance of approximately 7.3km (34 – 26.7) of roadway still
to be resurfaced to clear the original 117km backlog.
The potential shortfall in clearing the original
backlog of 117km can be attributed to two main factors. First, the cost of rehabilitation has increased
from approximately $156,000.00 per two lane km in 2001 to approximately $176,000.00
per two lane km in 2004. This
inflationary effect of approximately 4% directly impacts our ability to
complete the projected number of kilometres within the intended time
frame. Second, the cost of undertaking
alternative rehabilitation strategies involving CIP and EA has not proven to be
more cost effective than undertaking traditional rehabilitation strategies such
as shave and pave. As discussed earlier,
it currently costs approximately $1.00/m2 more to undertake an asphalt recycling strategy as
opposed to shave and pave.
Looking further into the future and utilizing our
current strategies, it is estimated that 104km of roadway will be at or exceeding
our thresholds for rehabilitation by the end of 2010. Based on the current estimated cost for road
rehabilitation of $176,000.00 per two lane kilometre (this price includes
repairs to concrete curbs, sidewalks, base asphalt and underground structures)
the Operations and Asset Management Department would require $3.5M to $4M (in
2004 dollars) per year over the period 2006 to 2010 (see Attachment 4).
FINANCIAL
CONSIDERATIONS:
The original five-year (2001-2005) Pavement Rehabilitation Program
identified 117km of roadwork. At the end
of 2004, it is projected that a total of 83km will be completed with a balance
of 34km remaining in 2005, the last year of the original program. Based on a proposed capital budget of $4.7M
(2004 dollars) and a current average cost of $176,000/km, it is estimated that
the 2005 program can accommodate approximately 26.7km of road. The shortfall, 7.3km, is estimated to cost an
additional $1,284,800 and can be brought forward into the 2006-2010 program. This raises
the needs in the period from 2006-2010 to approximately $4M (in 2004 dollars)
per year.
BUSINESS UNITS
CONSULTED AND AFFECTED:
None
Attachments:
Attachment
1 Glossary of Terms
Attachment 2 Cost
Comparison – Conventional Asphalt Rehabilitation Strategies Vs Alternative
Asphalt Rehabilitation Strategies
Attachment
3 Proposed Pavement
Rehabilitation Program Vs Actual Roads Completed
Attachment 4 Projected
Resurfacing Costs
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Peter Loukes, Director of Operations &
Asset Management |
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Jim Sales, Commissioner of Community &
Fire Services |
Q:\Commission Share\Operations
and Asset Management\Reports\2004\Operations\Pavement Management Update
2004_1.doc
ATTACHMENT 1
GLOSSARY OF TERMS
Chip Seal – a surface treatment in
which a pavement surface is sprayed with asphalt (generally emulsified) and
then immediately covered with aggregate and rolled. Chip seals are used primarily to seal the
surface of a pavement with non load-associated cracks and to improve surface
friction, although they also are commonly used as a wearing course on low
volume roads.
Cold In-Place Recycling (CIR) – a process in which a
portion of an existing bituminous pavement is pulverized or milled, the
reclaimed material is mixed with new binder and, in some instances, virgin
aggregates. The resultant blend is
placed as a base for a subsequent overlay.
Emulsified asphalt is especially suited for cold in-place
recycling. Although not necessarily
required, a softening agent may be used along with the emulsified asphalt.
Cold Milling – a process of removing pavement material from the
surface of the pavement either to prepare the surface (by removing rutting and
surface irregularities) to receive overlays, to restore pavement cross slopes
and profile, or even to re-establish the pavement’s surface friction
characteristics.
Corrective Maintenance – maintenance performed once
deficiency occurs in the pavement; i.e. loss of friction, moderate to severe
rutting, extensive cracking or raveling.
Crack Filling – the placement of materials
into non-working cracks to substantially reduce infiltration of water and to
reinforce the adjacent pavement. Working
cracks are defined as those that experience significant horizontal movements,
generally greater than about 2 mm (0.1 in.).
Crack filling should be distinguished from crack sealing.
Crack Sealing – a maintenance procedure
that involves placement of specialized materials into working cracks using
unique configurations to reduce the intrusion of incompressibles into the crack
and to prevent intrusion of water into the underlying pavement layers. Working cracks are defined as those that
experience significant horizontal movements, generally greater than about 2mm
(0.1in.).
Emulsified Asphalt – an emulsion of asphalt
cement and water, which contains a small amount of emulsifying agent. Emulsified asphalt droplets, which are
suspended in water, may be either the anionic (negative charge) or cationic
(positive charge) type, depending upon the emulsifying agent.
Hot In-Place Recycling (HIR) – a process which consists
of softening the existing asphalt surface with heat, mechanically removing the
surface material, mixing the material with a recycling agent, adding (if
required) virgin asphalt and aggregate to the material, and then replacing the
material back on the pavement.
Hot Mix Asphalt (HMA) – high quality, thoroughly
controlled hot mixture of asphalt cement and well graded, high quality
aggregate thoroughly compacted into a uniform dense mass.
Micro surfacing – a mixture of polymer modified asphalt emulsion, mineral aggregate,
mineral filler, water, and other additives, properly proportioned, mixed and
spread on a paved surface.
Pavement Preservation – the sum of all activities
undertaken to provide and maintain serviceable roadways. This includes corrective maintenance and
preventive maintenance, as well as minor rehabilitation projects.
Pavement Preventive Maintenance – planned strategy of
cost-effective treatments to an existing roadway system and its appurtenances
that preserves the system, retards future deterioration, and maintains or
improves the functional condition of the system (without increasing the
structural capacity).
Pavement Reconstruction – construction of the
equivalent of a new pavement structure which usually involves complete removal and
replacement of the existing pavement structure including new and/or recycled
materials.
Pavement Rehabilitation – work undertaken to extend
the service life of an existing pavement. This
includes the restoration, placing an overlay, and/or other work required to
return an existing roadway to a condition of structural and functional
adequacy.
Pavement Serviceability Index (PSI) – a subjective rating of the
pavement condition made by a group of individuals riding over the pavement.
Rejuvenating Agent – similar to recycling agents in material
composition, these products are added to existing aged or oxidized HMA
pavements in order to restore flexibility and retard cracking.
Slurry Seal – a mixture of slow setting emulsified asphalt, well
graded fine aggregate, mineral filler, and water. It is used to fill cracks and seal areas of
old pavements, to restore a uniform surface texture, to seal the surface to
prevent moisture and air intrusion into the pavement, and to provide skid
resistance.
Q:\Finance and Administration\Finance\Purchasing\2004
File Management\Pavement Management Update 2004_1 Draft.doc
