# ASTM E2840-11 (Reapproved 2015)

Designation: E2840 − 11 (Reapproved 2015)Standard Practice forPavement Condition Index Surveys for InterlockingConcrete Roads and Parking Lots1This standard is issued under the fixed designation E2840; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (´) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice is used to assess the condition of roads andparking lots surfaced with interlocking concrete pavementthrough visual surveys using the Pavement Condition Index(PCI) method of quantifying pavement condition.1.2 The PCI for roads and parking lots was developed by theU.S. Army Corps of Engineers (1, 2). It is further verified andadopted by DOD and APWA. This standard is an adaptation ofthe PCI method for interlocking concrete pavements.1.3 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.2. Terminology2.1 Definitions of Terms Specific to This Standard:2.1.1 additional sample, n—a sample unit inspected inaddition to the random sample units to include non represen-tative sample units in the determination of pavement conditionindex. This includes very poor or excellent samples that are nottypical of the section and sample units. If a sample unitcontaining an unusual distress is chosen at random, it should becounted as an additional sample and another random sampleunit should be chosen. If all sample units are inspected, thenthere are no additional samples.2.1.2 interlocking concrete pavement, n—discrete, hand-sized paving units with rectangular or dentated shapes manu-factured from concrete and conforming toASTM C 936. Eithertype of unit shape is placed in an interlocking pattern withvarious jointing and bedding materials over an unbound orbound base layer.2.1.3 pavement branch, n—a branch is an identifiable part ofthe pavement network that is a single entity and has a distinctfunction. For example, each roadway or parking area is aseparate branch of a pavement network.2.1.4 pavement condition index (PCI), n—a numerical rat-ing of the pavement condition that ranges from 0 to 100 with0 being the worst possible condition and 100 being the bestpossible condition.2.1.5 pavement condition rating, n—a verbal description ofpavement condition as a function of the PCI value that variesfrom “failed” to “excellent” as shown in Fig. 1.2.1.6 pavement distress, n—external indicators of pavementdeterioration caused by loading, environmental factors, con-struction deficiencies, or a combination thereof. Typical dis-tresses include depressions, damaged pavers, horizontal creepand faulting. Distress types and severity levels detailed inAppendix X1 must be used to obtain an accurate PCI value.2.1.7 pavement sample unit, n—a sample unit is a subdivi-sion of the pavement section. Each pavement section is dividedinto sample units for the purpose of pavement inspection. Thesample units for inspection shall be 2500 ft26 1000 ft2(225m26 90 m2).2.1.8 pavement section, n—a contiguous pavement areahaving uniform construction, maintenance, usage history, andcondition. A section should have the same traffic volume andload intensity.2.1.9 random sample, n—a sample unit of the pavementsection selected for inspection by random sampling techniques.3. Summary of Practice3.1 The pavement is divided into branches that are thendivided into sections. Each section is divided into sample units.The type and severity of pavement distress is assessed byvisual inspection of the pavement sample units. The quantity ofdistress is measured as described in Appendix X1 and Appen-dix X2. The distress data is used to calculate the PCI for eachsample unit. The PCI of a pavement section is determinedbased on the PCI of the inspected sample units within thesection.4. Significance and Use4.1 The PCI is a numerical indicator that rates the surfacecondition of the pavement. The PCI provides a measure of thepresent condition of the pavement based on the distressobserved on the surface of the pavement, which also indicates1This practice is under the jurisdiction of ASTM Committee E17 on Vehicle -Pavement Systems and is the direct responsibility of Subcommittee E17.42 onPavement Management and Data Needs.Current edition approved Sept. 1, 2015. Published December 2015. Originallyapproved in 2011 as E2840– 11. DOI: 10.1520/E2840–11R15Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1the structural integrity and surface operational condition (lo-calized roughness and safety). The PCI does not measurestructural capacity nor does it provide direct measurement ofskid resistance or roughness. It provides an objective andrational basis for determining maintenance and repair needsand priorities. Regular monitoring of the PCI is used toestablish the rate of pavement deterioration, which permitsearly identification of major rehabilitation needs. The PCI canalso provide feedback on pavement performance for validationor improvement of current pavement design and maintenanceprocedures.4.2 The PCI procedure for interlocking concrete pavementswas developed by surveying many sample units. Additionalverification of the accuracy and repeatability of the PCIprocedure for interlocking concrete pavements remains to beperformed.5. Apparatus5.1 Data Sheets, or other field recording instruments thatrecord the date, location, branch, section, sample unit size,distress types, severity levels, quantities, and names of survey-ors. Example data sheets are shown in Fig. 2 and Fig. 3.5.2 Hand Odometer Wheel, that reads to the nearest 0.1 ft(30 mm).5.3 Straightedge or String Line,10ft(3m).5.4 Scale, 12 in. (300 mm) that reads to 1/16 in. (1 mm).Anadditional 12 in. (300 mm) ruler or straightedge is needed tomeasure faulting.5.5 Layout Plan, for network to be inspected.6. Hazards6.1 Traffic is a hazard as inspectors may walk on thepavement to perform the condition survey.7. Sampling and Sample Units7.1 Identify branches of the pavement with different usessuch as roadways and parking on the network layout plan.7.2 Divide each branch into sections based on the pavementtype, construction history, traffic, and condition.7.3 Divide the pavement sections into sample units.7.4 Individual sample units to be inspected should bemarked or identified in a manner to allow inspectors andquality control personnel to easily locate them on the pavementsurface. Paint marks along the edge and sketches with locationsconnected to physical pavement features are acceptable. It isnecessary to be able to accurately relocate the sample units toallow verification of current distress data, to examine changesin condition with time of a particular sample unit, and to enablefuture inspections of the same sample unit if desired.7.5 Select the sample units to be inspected. The number ofsample units to be inspected may vary from the following: allof the sample units in the section, a number of sample units thatprovides a 95 % confidence level, or a lesser number.7.5.1 All sample units in the section may be inspected todetermine the average PCI of the section. This is usuallyprecluded for routine management purposes by availablemanpower, funds, and time. Total sampling, however, isdesirable for project analysis to help estimate maintenance andrepair quantities.7.5.2 The minimum number of sample units (n) that must besurveyed within a given section to obtain a statisticallyadequate estimate (95% confidence) of the PCI of the sectionis calculated using the following formula and rounding n to thenext highest whole number (see Eq 1).FIG. 1 Pavement Condition Index (PCI), Rating Scale, and Sug-gested ColorsE2840 − 11 (2015)2FIG. 2 Blank Interlocking Concrete Pavement Condition Index SheetE2840 − 11 (2015)3n 5 Ns2/~~e2/4!~N 2 1!1s2! (1)where:e = acceptable error in estimating the section PCI;commonly, e = 65 PCI points;s = standard deviation of the PCI from one sample unit toanother within the section. When performing the initialinspection the standard deviation is assumed to be 10 forinterlocking concrete pavements. This assumptionshould be checked as described below after PCI valuesare determined. For subsequent inspections, the standarddeviation from the preceding inspection should be usedto determine n; and,N = total number of sample units in the section.7.5.2.1 If obtaining the 95% confidence level is critical, theadequacy of the number of sample units surveyed must beconfirmed.The number of sample units was estimated based onan assumed standard deviation. Calculate the actual standarddeviation (s) as follows (see Eq 2):s 5S(i51n~PCIi2 PCIs!2/~n 2 1!D12(2)where:PCIi= PCI of surveyed sample units i,PCIs= PCI of section (mean PCI of surveyed sample units),andn = total number of sample units surveyed.FIG. 3 Completed Interlocking Concrete Pavement Condition Index SheetE2840 − 11 (2015)47.5.2.2 Calculate the revised minimum number of sampleunits (Eq 1) to be surveyed using the calculated standarddeviation (Eq 2). If the revised number of sample units to besurveyed is greater than the number of sample units alreadysurveyed, select and survey more random sample units. Thesesample units should be spaced evenly across the section.Repeat the process of checking the revised number of sampleunits and surveying more random sample units until the totalnumber of sample units surveyed equals or exceeds theminimum required sample units (n)inEq 1, using the actualtotal sample standard deviation.7.5.3 Once the number of sample units to be inspected hasbeen determined, compute the spacing interval of the unitsusing systematic random sampling. Samples are spaced equallythroughout the section with the first sample selected at random.The spacing interval (i) of the units to be sampled is calculatedby the following formula rounded to the next lowest wholenumber:I 5 N/n (3)where:N = total number of sample units in the section, andn = number of sample units to be inspected.The first sample unit to be inspected is selected at randomfrom sample units 1 through I. The sample units within asection that are successive increments of the interval i after thefirst randomly selected unit also are inspected.7.6 A reduced sampling rate than the above mentioned 95%confidence level can be used based on the condition surveyobjective. The following table provides an example used bysome agencies for selecting the number of sample units to beinspected for other than project analysis:Given Survey1 to 5 sample units 1 sample unit6 to 10 sample units 2 sample units11 to 15 sample units 3 sample units16 to 40 sample units 4 sample unitsover 40 sample units 10%7.7 Additional sample units only are to be inspected whennon-representative distresses are observed. The location ofthese sample units is determined during the survey by theinspector.8. Inspection Procedure8.1 The definitions and guidelines for quantifying distressesfor PCI determination are given in Appendix X1. Using thistest method, inspectors should identify distress types accu-rately 95% of the time. Linear measurements should beconsidered accurate when they are within 10% if remeasured,and area measurements should be considered accurate whenthey are within 20% if remeasured. Distress severities that onedetermines based on ride quality are considered subjective.8.2 Individually inspect each sample unit chosen. Sketch thesample unit, including orientation. Record the branch andsection number and the number and type of the sample unit(random or additional). Record the sample unit size measuredwith the hand odometer. Conduct the distress inspection bywalking over the sample unit being surveyed, measuring thequantity of each severity level of every distress type present,and recording the data. Each distress must correspond in typeand severity to that described in Appendix X1. The method ofmeasurement is included with each distress description. Thisprocedure should be repeated for each sample unit to beinspected. An example of a blank Interlocking ConcretePavement Condition Survey Data Sheet for Sample Unit isincluded in Fig. 1 and a completed data sheet is shown in Fig.2.9. Calculation of PCI9.1 Add up the total quantity of each distress type at eachseverity level, and record them in the “Total Severities”section. The units for the quantities may be either in square feet(square meters), linear feet (meters), or number of occurrences,depending on the distress type.9.2 Divide the total quantity of each distress type at eachseverity level by the total area of the sample unit and multiplyby 100 to obtain the percent density of each distress type andseverity.9.3 Determine the deduct value (DV) for each distress typeand severity level combination from the distress deduct valuecurves in Appendix X3.9.4 Determine the maximum corrected deduct value (CDV).The following procedure must be used to determine themaximum CDV.9.4.1 If none or only one individual deduct value is greaterthan two, the total value is used in place of the maximum CDVin determining the PCI; otherwise, maximum CDV must bedetermined as follows.9.4.2 List the individual deduct values in descending order.Determine the allowable number of deducts, m, using thefollowing formula (see Eq 4):m 5 11~9/98!~100 2 HDV! #10 (4)where:m = allowable number of deducts including fractions(must be ≤ 10),HDV = highest individual deduct value.9.4.3 The number of individual deduct values is reduced tothe m largest deduct values, including the fractional part. If lessthan m deduct values are available, all of the deduct values areused.9.4.4 Determine maximum CDV iteratively.9.4.4.1 Determine total deduct value by summing individualdeduct values. The total deduct value is obtained by adding theindividual deduct values.9.4.4.2 Determine q as the number of deducts with a valuegreater than 2.0.9.4.4.3 Determine the CDV from total deduct value and qby looking up the appropriate correction curve (Appendix X3).9.4.4.4 Reduce the smallest individual deduct value greaterthan 2.0 to 2.0 and repeat until q = 1. The maximum CDV isthe largest of the CDVs.9.5 Calculate PCI by subtracting the maximum CDV from100: PCI = 100 - max CDV.E2840 − 11 (2015)510. Determination of Section PCI10.1 If every sample unit is surveyed then the PCI of thesection is the average of the PCIs of the sample units. Ifadditional sample units are surveyed then a weighted averageis used as follows:PCIS5 ~N 2 A!~PCIR!/N1A~PCIA!/N (5)where:PCIS= weighted PCI of the section,N = total number of sample units in the section,A = number of additional sample units,PCIR= mean PCI of randomly selected sample units, andPCIA= mean PCI of additional selected sample units.10.2 Determine the overall condition ratin