HomeMy WebLinkAboutAssessmentFY 2017-2018
Pavement Assessment
I. SUMMARY
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HOME OF PELICAN ISLAND
A citywide pavement assessment was conducted during the month of September 2017 to
identify and inventory streets in the City of Sebastian which will require pavement repair or
resurfacing. The assessment required a field review of each street to visually inspect the
asphalt surface and to rate each street based on the pavement condition. Streets were rated
into one of three pavement categories and then shown on a citywide map. The report provides
a summary of streets to be resurfaced for the next five years.
IL BACKGROUND
The City of Sebastian maintains approximately 157 miles of paved streets which includes
local residential and collector streets. A majority of these streets were constructed back in the
late 1950's and 1960's approximately 30 to 40 years ago. The local streets are typically 17-19
feet wide with no curb and gutter. The collector streets are typically 20-24 feet wide with no
curb and gutter. The City has the following major collector streets per the City's Circulation
Element:
• Indian River Drive
• Schumann Drive
• Barber Street
• Fleming Street
• Easy Street
• Vocelle Avenue
• Main Street
• Laconia Street
• Englar Avenue
• Wimbrow Drive
• Louisiana Ave
Most of these collector streets were constructed with a typical 6 to 8 inches of a soil cement
treated base material under an asphalt pavement surface that varied from %z" to 2" thick of
asphalt pavement. All of the recently reconstructed collector streets (2015-2017) like Barber
Street and Vocelle Avenue were reconstructed with 8 inches of coquina rock based under 2"
of asphalt pavement.
III. FIELD REVIEW
The field review required driving each street to visually inspect the existing pavement surface
condition. A pavement assessment includes the visual drive-by inspection of the pavement
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surface to evaluate the surface riding condition and to determine if any additional structural
analysis is required due to possible base failure. The pavement surfaces are evaluated on the
adequacy of the existing pavement for vehicle use and riding condition. Streets are rated on
signs of pavement distress, ride -ability and the present serviceability life. Streets with signs
of surface distress relating to base failure are inventoried for possible structural analysis of the
base material prior to any repair work. Before embarking upon any substantial capital
investment to repair or reconstruction streets due to base failure, the pavement assessment
will help to prioritize street repairs by rating the severity of the distressed conditions and to
analyze how each problem should be solved by resurfacing or reconstruction. In most cases,
pavement distresses can be repaired by street resurfacing. The following are types of
pavement distresses:
Fatigue Cracking
Fatigue cracking is known as alligator cracking due to the block style cracks which resemble
an alligator skin. Fatigue cracking is caused by heavy traffic load resulting in deterioration of
the base, weakening of the subbase and typically poor drainage adds to the surface cracking
and eventually to base failure.
Block Cracking
Block cracking is a series of large rectangular cracks on the pavement surface. This type of
cracking is typically due to old and dried fine aggregate mix. This type of cracking is a
mixture failure and not traffic load related. Block cracking is typically caused by the
shrinkage of the asphalt pavement due to temperature cycles during the mixture.
Edge Cracking
Edge cracks are longitudinal cracks which develop within one or two feet of the outer edge of
a pavement. Lack of lateral support and settlement of the base material due to a weak base
structure. Poor drainage due to heavy vegetation along the edge and not allowing drainage to
runoff the pavement will cause edge cracking.
Longitudinal Cracking
Longitudinal cracks occur parallel to the centerline of the pavement travel lanes. The cause is
poorly constructed paving joints and shrinkage in asphalt layer and longitudinal pavement
cracks reflecting up from an underlying layer and longitudinal segregation due to improper
paver operation. These types of cracks are not traffic load -related.
Transverse Cracking
Transverse cracks occur roughly perpendicular to the centerline of the pavement. They can be
caused by shrinkage of the asphalt layer or reflection from an existing surface crack. These
types of cracks are not traffic load -related, but poor drainage will cause the cracking to
increase and eventually cause base failure.
Reflection Cracking
Reflection cracks form over joints or cracks in concrete pavement or in an overlay of a
deteriorated asphalt pavement surface. Reflection cracks are also formed in pavement from a
cement treated base. The cause is differential movement between the asphalt and the base
layer and deterioration due to heavy traffic.
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Rutting.
Rutting is a linear surface depression in the wheel path of the travel lane. Rutting is caused by
deformation or consolidation of any of the pavement layers or subbase. The cause is typically
due to insufficient base thickness, lack of compaction, weakened in pavement layer and
mixture and weak asphalt mixtures.
Shoving.
Shoving is the formation of ripples across the pavement surface. The characteristic shape of
the ripples is why this type of distress is sometimes called wash -boarding. Shoving occurs at
locations having severe horizontal stresses, such as driveways and intersections. It is typically
caused by excess asphalt with fine aggregate and a weak granular base.
Depressions.
Depressions which are call bird -baths, are localized low spots in the pavement surface. These
flaws can be caused by settlement or other failure in the lower pavement layers or by poor
construction techniques.
Patch Failure
When asphalt pavement is patched for repair, some distress may begin to occur at the edge of
the connection from the existing to the new asphalt pavement. The rate at which a patch
deteriorates is influenced by the compaction, type of asphalt and the quality of the
surrounding pavement or underlying base material.
Raveling
Raveling is the wearing away of the aggregate particles from the asphalt mixture. The cause
is from the asphalt binder hardened excessively, poor quality asphalt mixture and heavy
traffic loads. In addition to the poor mixture and traffic loads, raveling is caused by poor
drainage and allow water to pool on top of the pavement surface.
Potholes
Potholes are bowl -shaped holes caused by the localized disintegration of the pavement
surface. Potholes typically result from the continued deterioration of a distress pavement due
to poor drainage and vehicle loads. Segregation of the asphalt, cracks or failed patches may
serve as the start of a pothole. In addition, weak spots in the structural base or subgrade can
accelerate pothole failures.
The pavement rating evaluation is a criteria identified in a typically Pavement Management
System to conduct field reviews and rate pavement surface conditions. Each street is driven
and given a rating based upon the quality of the pavement surface condition based on site
observation and ride -ability. Each street is rated into one of three basic categories:
• Good condition of the pavement surface
• Poor condition (minor/medium surface cracking and pot holes) of surface
• Bad condition (large cracking and base failures) of surface
The rated streets are graphically shown on a citywide map to display the overall total number
of streets in "Poor or Bad" condition.
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A. Pavement Rating Survey
The pavement rating of streets were completed during the month of September 2017. The
surface ratings were performed by a licensed Florida Professional Engineer with experience in
inspecting and rating distressed pavement conditions. These ratings are objective based on
the engineer's field review of the surface condition and pavement ride -ability. As mentioned,
these streets were rated in one of three different levels of pavement classification to determine
the amount of repair that would be required on each street. The following is a brief definition
of each pavement classification.
Good (No Color). Roads that have been paved within the last 10-12 years and are
holding up well. They are in good condition and can be expected to not require
paving for several years or more.
Poor (Orange). Roads that are in poor pavement condition and need repair. It is
potholed and/or cracked and is in need of significant repair, then resurfacing may
need to be addressed. Immediate attention is indicated.
Bad (Purple). Roads are bad condition with base failure and major surface
cracking. The roadway base material such as the coquina rock or lime rock is
failing. Additional work will be required to reconstruct the road base and apply
more material, if necessary.
A color inventory map of streets in "Poor or Bad" condition is shown on the following page
of this report. This map graphically displays each street per color rated classification as listed
above.
B. Streets Recommended for Resurfacing (Milling and Paving)
Streets rated as "Poor" or "Bad" will be prioritized as possible candidates for pavement
resurfacing or possibly street reconstruction based on any additional structural review of the
base material. As shown on the following page in the color city map, there are several streets
which fall into these two categories. The following table provides a summary of the 2017
pavement assessment which identifies the street miles percentage in poor or bad condition and
the percent change within each of the three categories. The findings show an increase of 36%
of streets in "Bad" pavement condition and 1.6% increase in the "Poor" pavement condition.
The majority of the City streets are still within the "Good" conditions.
Pavement
Condition
2015 Pavement
2017 Pavement
Change %
Rating
(miles)
(miles)
Good
132.6
129.2
-2.6%
(no color)
Poor
18.8
19.1
1.6%
(Orange)
Bad
5.6
8.7
36%
(Purple)
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C. Preparation for Resurfacing.
The purpose of this section is to identify specific preparation work that should be performed
prior to any street resurfacing. These preparations are essential to eliminate the possible cause
and to help ensure the life of the new pavement. Each street rated in poor or bad condition
will require some amount of preparation prior to the resurfacing. It is of the utmost
importance to the life of the new asphalt pavement to have a clean, stabilized surface upon
which to place the new asphalt. A sound and solid base is required as well. Areas that have
evidence of deterioration due to standing water should be reviewed and given additional
consideration for drainage improvements. Street resurfacing should consist of the following
preparation tasks:
• Drainage. Roads that have a history of drainage problems should be reviewed to
determine what level of drainage work is needed to eliminate standing water on the
road surface. Road failures are mainly due to lack or poor roadway drainage which
include; clogged or collapsed pipes, inadequate swales and lack of ditch maintenance
contribute to road failure when the water cannot run off the pavement surface into a
drainage facility. Prior to any roadway improvements, the drainage facilities, such as
storm drain pipes under the roadway, culverts and drainage boxes should be inspected
for any needed improvements. These drainage improvements should typically be
constructed as separate drainage improvement projects and not tied into the roadway
and pavement project.
• Shoulders & Swales. The shoulders should be inspected to determine the elevation of
the roadway surface. If the shoulder is too high, then water will not be able to drain
off of the road. Roads that have evidence of holding water due to high swales will be
more closely scrutinized to determine if the seriousness of the water retainage
warrants additional drainage work prior to the resurfacing. The swates will only be
improved to the end result of getting water off of the road. The drainage efforts
expended under the paving program will only involve repairing failed pipes, cut
shoulders to provide positive drainage off of the road, sod and/or seed and mulch
shoulders.
• Edging. The existing edge of the pavement must be clear and clean from grass and
debris. Procedures for clearing the edge consist of grading or excavating overgrown
vegetation and exposing the edge of the original pavement. Brooming off the loose
material and herbicide application if there is vegetation growth through the base.
• Crack Sealing. Cracks that have formed in the roadway surface should be sealed if
they have greater than I inch width. Herbicide is applied if there is vegetation growth.
Sealants will repair the crack and give a smooth surface upon which new asphalt
overlay can be applied.
• Patches & Potholes. Potholes and broken asphalt must be repaired if they are 3
inches in depth or greater. Imperfections less than 3 inches can be smoothed out with
an application of a leveling course of asphalt prior to the overlay. Some areas that
have asphalt peeled away, can be scraped off with a motor grader to the original base
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and a leveling course applied. Only those potholes greater than 3 inches deep will
require more attention than a leveling course.
Spraying. Areas where grass and other vegetation are growing from beneath the
paved surface will require herbicide spraying prior to asphalt application.
Brooming. The road surface must be clean and dry prior to the placement of new
asphalt application.
Milling. Milling is the process in which the top 2 inches of asphalt and possibly the
road base. Milling is proposed for street which show extremely deteriorated pavement
surface and there is some indication of base failure. After the existing pavement is
milled, the base is inspected to ensure no base failures.
D. Pavement Conditions
In general, the distressed pavement condition can be repaired with only the resurfacing which
is typically considered a "Mill and Paving" construction. If the pavement deficiency has
damaged the base material of the roadway, then the structure base material will need to be
repaired or reconstructed. The City typically will reconstruct based failure street using a
street reconstruction method known as "Full Depth Reclamation".
1. Asphalt Overlays & Leveling Course. All roads shall be resurfaced with a
minimum of 1 inch and up to 2 inch thick asphalt overlay. Dependent upon the
existing road surface, a leveling course may be applied prior to the overlay. Roads
with rough surfaces, imperfections, or wheel ruts will be leveled prior to resurfacing.
Most of the roads will require some leveling or patching. One half inch ('/2) of
asphalt over each lane was used to estimate the number of tons required for the level
course.
2. Full Depth Reclamation (FDR) with Recycled Cement Treated Base. Full depth
reclamation recycles the materials from the deteriorated asphalt pavement, base
material and with the addition of cement, creates a new stabilized base. A surface
consisting of a then bituminous hot mix asphalt or concrete cement completes the
rebuilt roadway. The recycled base is stronger, more uniform and more moisture
resistant than the original base resulting in a long, low -maintenance life.
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