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Road Surface Management System Flexible Pavement Condition Surveys August 2006. Our Technique.
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Road Surface Management System Flexible Pavement Condition Surveys August 2006
Our Technique... We completed an RSMS Flexible Pavement Condition Survey for approximately every 1000ft on every public road in Bolton. These completed sheets can be found in the Bolton DPW Office. They rate the section of road on seven conditions. This data was compiled into Excel sheets and graphs that can be found in the front of the 2006 Binder.
The Survey... • Alligator Cracking • Longitudinal/Transverse Cracking • Edge Cracking • Patching/Potholes • Drainage • Roughness • Rutting
NO Defects Low Med High Low Med High EXTENT 1 2 3 4 5 6 7 8 9 SEVERITY Alligator Cracking Alligator cracks are interconnected cracks, forming a series of small blocks resembling an alligator’s skin. This occurs when the sub-base gravel fails to provide adequate support for the asphalt pavement. It is also known as fatigue cracking, and repeated heavy loads and moisture create excess flexing of the surface.
NO Defects Low Med High Low Med High EXTENT 1 2 3 4 5 6 7 8 9 SEVERITY Longitudinal/Transverse Cracking Longitudinal cracks are individual and run parallel to the centerline. Transverse cracks run perpendicular to the centerline. They are caused by inadequate bonding between paving lanes or asphalt shrinkage from low temperatures.
NO Defects Low Med High Low Med High EXTENT 1 2 3 4 5 6 7 8 9 SEVERITY Edge Cracking Edge cracks are approximately 1ft from the road edge. Normally they are caused by lack of shoulder support, or by the settlement of the material under the edge. This can indicate poor drainage, frost heaves, or shrinkage of the surrounding earth.
NO Defects EXTENT (0) (2) (5) GOOD FAIR POOR Patching/Potholes Potholes arise when the wearing surface disintegrates under traffic, due to inadequate structural strength in one or more layers of the pavement. They are bowl-shaped voids and are often located in areas of poor drainage. Patches are portions of pavement that have been removed and replaced, usually to repair defects in the pavement. Problems occur when the patches crack, settle, or distort.
Drainage Inadequate drainage is important to document because of the long-term affects of moisture on pavement. Rain falling on pavement should be efficiently directed to drains and catch basins. Poor drainage can damage the concrete, weaken the sub-grade, etc. NO Defects CONDITION GOOD FAIR POOR SEVERITY
Roughness The roughness of a road is determined by the severity of uneven surfaces, corrugations, sags, humps, frost heaves and the previous survey conditions. CONDITION GOOD FAIR POOR SEVERITY
CONDITION (0) (8) No visible rutting (<1 in.) Rutting visible (>1 in.) SEVERITY Rutting Rutting is the displacement of pavement material that creates channels in the wheel path and is sometimes referred to as channeling.
The Data We compiled all of this information into spreadsheets, and we devised and grading system for each condition so all the roads can be compared. All this data is subjective, and you may not agree with every score, but this is a sufficient way of determining which roads need the most attention. There are many ways of organizing this data, and a few of these ways will be presented here, so as to create a good picture of the road conditions. The following graphs are using average numbers. The full sheets divided by each section are the best indication of which portion of a road needs the most attention, but for general road conditions, averages are useful to tell the best from the worst.
The Plan • In an ideal scenario: have enough money to redo each road with just the occasional maintenance • Plan: to separate the roads into deciles and bring all the roads into that top 10% score (0-3) • Achieved by paving or reconstructing the worst roads, or the sections of a road that are bringing the averages up, and then crack sealing and patching the roads in the middle range • If all the roads have this low score then repave appropriately • Repairing drainage issues and cracks will prolong the life of a road at least 4-5 years, by preventing damaging moisture from harming the sub-bases, which in turn adds more issues to the top layer of pavement • Ultimate goal: have all the roads in this 10% range, avoiding disasters like Spectacle Hill in the future
The Plan Numbers shown under severity are averages of all the cracks found. These data tables present the roads that their overall condition is good, yet could use some attention to keep them in a ‘good’ condition. As stated before, this can be achieved by patching and repairing the deformities.
The Plan These data tables present the roads in fair/good condition. As shown, most of the roads have all the different types of cracks and many of them have a higher severity average. These are the roads that need to be attended to soon or they have or may be past the ‘patching’ stage.
The Plan • Roads in Order (worst to better) • Spectacle Hill Road • Burnham Road • Old Harvard Road • Powder Hill Road • Meadow Road • Forbush Mill Road • Teele Road • McNulty Road This data table presents the roads that are in the 50% or more percentile in overall condition. These are the worst roads in town according to our findings.
75% Time 40% Quality Drop Each $1 of Renovation Cost Here… Will Cost $4 to $5 if Delayed to Here 40% Quality Drop 17% Time Years Normal Pavement Deterioration