PAVEMENT CONDITION SURVEYS

1 PAVEMENT CONDITION SURVEYS5-1 PAVEMENT CONDITION Module ObjectivesThe objectives of this module are to enable participants to:n Understand the need for CONDITION Be familiar with the four basic types of CONDITION Acquaint participants with the different procedures and equipment Be aware of the purpose, advantage and disadvantage of different IntroductionIn the previous module, the inventory defined the network for which the pavementengineer is responsible. In this module, CONDITION SURVEYS are used to assess ordescribe the state of being, or readiness for use, of those elements being managed.

2 Ithas also been described as a means of determining the health of the CONDITION survey is the process of collecting data to determine the structural integrity,distresses, skid resistance, and overall riding quality of the PAVEMENT . Traditionally,maintenance or engineering personnel relied on experience and visual inspections toschedule maintenance. The problems with that technique are that experience isdifficult to transfer from one person to another and decisions made using similar dataoften vary considerably. CONDITION SURVEYS provide a rational and consistent method ofallocating limited monitoring the PAVEMENT CONDITION using the methods described here, an agencyshould be able to.

3 N Evaluate the current CONDITION of the Determine the rates of Project future Determine maintenance and rehabilitation Determine the costs of Prepare plans for Determine the effects of budget reductions and deferred Schedule future PAVEMENT maintenance Track performance of various PAVEMENT designs and are several methods available for defining the current CONDITION of a pavementsegment. Many of the PAVEMENT management systems (PMS) available use a specificmethod of collecting CONDITION data and defining states of PAVEMENT readiness orcondition.

4 Adopting a specific PMS will often require the adoption of specific datacollection so many decisions supported by the PMS are based on the CONDITION assessment,it is important to ensure that the data collected and used is accurate enough to providethe desired level of support. However, since the collection of CONDITION data is thePAVEMENT CONDITION SURVEYS5-2most expensive portion of maintaining the PMS, the cost must be matched to theresources and needs of the adopting published literature on CONDITION SURVEYS is extensive and exhaustive. Much of thepreviously published work, as well as past NHI courses, are summarized PMS courses were especially useful in compiling this module.

5 The focus ofthis module will be on new types of procedures and Collection MethodologiesCollecting CONDITION information is generally the most costly part of the initialimplementation of a PMS and of continued operation. CONDITION data can be collectedusing very expensive or relatively inexpensive methods. In general, the detail andaccuracy of data collection varies from very detailed for research activities to verygross for some network-level management systems. It is not necessary to have thesame detail at each level; however, it is important to use the same general definitions ateach level. It is not necessary to collect all of the data at each level.

6 Some measures,such as structural evaluation, may only be collected at the project-level. Othermeasures, such as surface friction, may only be used when a specific problem has different methods are available to collect each of these CONDITION measures. Themethods that are more costly are also usually more accurate, more precise, and have thegreatest resolution. Accuracy is the degree to which the method provides a true is the repeatability among multiple measurements. Resolution is the smallestincrement that can be measured. The precision, accuracy, and resolution neededdepend on the goals of the PAVEMENT management system and the funds available topay for the inspection services.

7 Some methods are more subjective than 1 and 3 describe many of the data collection methods and equipment insome detail. Reference 4 discusses many of the automated or semi-automatedprocedures for collecting and analyzing distress data. Reference 5 presents somecriteria that should be considered in selecting the data and collection types of SurveysAssessing the PAVEMENT CONDITION begins with collecting data. This data is theninterpreted to define the current state of readiness, or health of the PAVEMENT . Thereare generally four types of SURVEYS (1):n Distress Surveysn Structural Capacityn Roughness (ride quality)n Skid Resistance (surface friction)The basic purpose of a PAVEMENT is to provide a safe and smooth surface for thetravelling public.

8 The travelling public is primarily interested in this functionalcondition, which is primarily measured with roughness and surface friction. Theengineers and managers are interested in developing the most cost-effectivemaintenance and rehabilitation program. They are interested in an engineering analysisof the CONDITION , as well as the functional CONDITION . Distress SURVEYS and structuraltesting are normally used in the engineering CONDITION SURVEYS5-3 DISTRESS SURVEYS : Surface distress is damage observed on the PAVEMENT surface. Distresssurveys are performed to determine the type, severity, and quantity of surface information is often used to determine a PAVEMENT CONDITION index (PCI), whichhelps compute a rate of deterioration, and is often used to project future CONDITION (2).

9 Surface distress and the current or future PCI values are often used to help identify thetiming of maintenance and rehabilitation as well as funding needs in the PMS is the measure most used by maintenance personnel to determine what type ofmaintenance treatment is required and when maintenance is needed. It is typically themost important type of CONDITION CAPACITY: Structural capacity is the maximum load and number of repetitions apavement can carry before reaching some defined CONDITION . Structural analysis isnormally conducted at the project-level to determine the PAVEMENT load-carryingcapacity and the capacity needed to accommodate projected traffic.

10 Non-destructivedeflection testing of the PAVEMENT is a simple and reliable method to assist in makingthis evaluation; however, destructive testing such as coring and component analysistechniques may be used as well. PAVEMENT structural evaluation is important in theselection of treatments at the project-levelROUGHNESS (RIDE QUALITY): Roughness, or ride quality, is a measure of PAVEMENT surfacedistortion along a linear plane or an estimate of the ability of the PAVEMENT to provide acomfortable ride to the users. Roughness is often converted into an index such as thePresent Serviceability Index (PSI) or the International Roughness Index (IRI).