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  • 1.  Pavement Serviceability Index

    Posted 03-27-2017 09:23 AM
    Hello. I have learnt the theoretical procedure of measuring Pavement Serviceability Index but I was told that the field procedures vary among different agencies. I am interested to know the filed methods followed so can you please share your field operations and its drawbacks. Thank you.

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    Surya Sarat Chandra S.M.ASCE
    Arlington TX
    (682)203-6894
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  • 2.  RE: Pavement Serviceability Index

    Posted 03-28-2017 09:52 AM
    We use MicroPaver from the APWA to assist us in the management of our streets.  It uses a Pavement Condition Index (PCI) vice a PSI, but same theory.  I think the key to getting a "good" number is to have the same person doing the initial inspection of the roads, if possible.  If not, the software comes with a booklet with photos of road conditions (rutting, alligator cracking, etc.) so that everyone has a common point of beginning as to the severity of the road conditions.  We update all roads that are resurfaced to 100% based on contracts issued / executed by the State/County.  As a minimum, I would have the inspectors at least start together and do some inspections as a group to establish a baseline in regards to severity so that the condition of the pavement will be consistent as possible throughout.  

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    Chuck Denson P.E., M.ASCE
    Assistant Director
    City Of Goose Creek
    Goose Creek SC
    (824)8242200
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    Original Message


  • 3.  RE: Pavement Serviceability Index

    Posted 03-29-2017 11:05 AM
    There are a few pavement condition assessment standards that are used widely among agencies that manage roadways.  The PASER method is a 1-10 scoring method where 10 is new and 1 needs to be reconstructed.  It is a visual assessment with no need to measure  and record amounts of distresses.  It is also done on segments and based on a sampling scheme.  PASER is mostly used by small agencies that have small roadway networks.  
    The PCI method, according to ASTM D6433 and its variations, is probably the most widely used pavement assessment method.  It uses the type, severity, and quantity of a list of distresses observed on a pavement surface to calculate an index of 0-100.  Pavement management software programs like (micro)PAVER and StreetSaver come pre-configured to allow for the PCI rating method.  Other more sophisticated systems such as Cartegraph OMS, RoadMatrix, and PavementAnalyst also allow for this method.  Since there are more and more of vehicles fitted with downward facing cameras and LCMS (laser crack measurement system) units being used to aid in pavement assessments, agencies and vendors are continually using a modified version of the PCI method.  This is because not all of the distresses that need to be identified according to the PCI method can be readily identified from the images collected by the survey vehicles.
    FHWA also has a distress identification manual used for the LTPP (long term pavement performance) program.  There are no indices calculated for this manual but it does allow the user to identify many distresses and have a record of their severity and quantity.

    There are a few other regionally accepted and used methods, like in the Northwest and in the Northeast, that are similar to the PCI method but these tend to only be popular in their respective regions.  Most State DOTs also have their own version and method of pavement assessment and condition reporting.  One thing is for sure, there is on single method that is universally used; therefore, pavement managers need to select the rating method that most suits their needs so that the agency can be successful in implementing and maintaining a sustainable pavement management program.  

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    Nathan Kebede P.E., M.ASCE
    Pavement Engineer
    Chicago IL
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    Original Message


  • 4.  RE: Pavement Serviceability Index

    Posted 03-30-2017 11:42 AM

    I think the biggest conundrum is subjectivity.  Even if the same person rates segments, there will be differences in time of day, freeze/thaw sensitivity based on elevation, roadway section thickness and cracking depths (plus bottom up cracking), rutting, deflections, polymers used in the asphalt, etc.  Objective automated road analysis with gpr, laser, deflection, friction measurements etc. at highway speeds is hugely cost effective in terms of a system-wide approach - to determine if sealing to replenish oxidized material (hugely cost effective in terms of pavement longevity) or what other maintenance procedures are appropriate.  Recent research has shown that the paradigm of "yes, sbs polymers make roads last longer, but eventually they break down" is incorrect - proper rejuvenation of the asphalt itself shows the sbs is undamaged (but that's a different story...).  The key is objective analysis through high speed automated surveys which can, at the same time, do inventory analyses as well.



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    Stephen Hemphill P.E., M.ASCE
    Semi-Retired
    Rio Rancho NM
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    Original Message


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