B Authors J N Buhan and H R Smiti PAWMENT PER~=CE AND DE~ECTION STUDIES ON MALAYSIAN ROADS by J N Buban and H R Smith This report describes a study of theperformance of nomally constructed road pavements in Peninsular Malaysia. Eight 1.6 km long lengths of road were selected for detailed Study . The quality and thickness of the pavement layers were examined, ‘the strengths of the stigrades were measured, and tie volfie and weight of the traffic transversing each site was monitored. The performance of the road pavements was assessed in terns of tie amount of cracking and rutting that developed in the road surface. In addition the deflection characteristics of the road pavements were monitored. Confirmation of pavement design recommendations A comparison of the pavement thicknesses of the eight road sites with TRRL and Shell pavement design recommendations 1’2~3 indicated tiat me pavements performed as would be predicted by the pavement design guides, tius confiming the applic~ility of these design recommendations in the Malysian environment. TWO of the sites received bituminous overlays of structurally significant thickness (greater than 50 mm) during the course of the study, and the others received thin maintenance overlays towards the end of the study. Only on one site was a sub-base provided and it is deduced that thf?lower part of the ‘crushed stone bases could have been replaced by lower grade and cheaper materials without reducing the lives of the pavements. The quality of the bitmir~ous surfacings was found to be generally low and it is concluded that higher quality but not necessarily thicker surfacings would have substantially increased the service lives of these pavements. Subgrade conditions Subgrade strengths were generally in excess of CBR 10 and stigrade densities were equal to, or higher, than the maximum dry density in the British Standard 2.5 kg (5.5 lb) rmer compaction test4. One hundred and ninety measurements of the,subgrade moisture content were made under the pavments at 73 different locations. More than half of these moisture contents were equal to or were drier than the optimm moistme content (OMC) of the s~bgrade soil given by the British Standard 2.5 kg (5.5 lb) rtier compaction test and three-quarters of them were drier than the OMC plus 2 per cent. The only places where subgrade moisture contents were wetter than this were where gross drainage deficiencies were apparent and free water was permitted to collect in the road bed. Deflection characteristics Histories of the deflection characteristics of the pavements were traced over an eleven-year period. These were related to the traffic passing over each site expressed in terms of the cumulative ntier of equivalent standard (82oo kgf) axles. It was found that it was inadvis~le to make deflection measuraents when pavement temperatures were less than 32°C because of the difficulty of establishing temperature/deflection relationships below this temperature. Pavement temperatures in Penisular Malaysia rarely fall below 30°C in daylight hours, and usually lie within the range 35°C to 450C. Deflection criterion curve ‘Deflection criterion curves’ 5 which relate ‘early life’ deflections to the stisequent traffic carrying capability of a pavement were developed for bitumen-macadam surfacings on crushed-stone bases in the Malaysian environment. Slightly different curves were obtained for the verge side and offside wheel tracks, a somewhat smaller early life deflection in tie verge side wheel track (as compared with tie offside wheel track) being required to ensure the sme pavement life. This is probably because moisture content changes in the subgrade and shoulder contribute to pavement deterioration more strongly at the edge of the road than near the road centre. Overlays The reduction in deflection effected by the laying of bitumen macadam overlays at two sites was monitored., Very scattered results were obtained at one site, no reduction in deflection being recorded at many points. At the other site more consistent results were obtained, but only about half the reduction in deflection was obtained as compared with the effect of hot-rolled asphalt overlays in Britain. This is probably mainly due to the higher pavement temperatures that commonly prevail in Malaysia, but the quality and density of bitwinous surfacing materials may also be factors. Conclusions The following conclusions can be drawn from this investigation:- 1. Current pavement design recommendations for flexible pavements set out in Road Notes 29 and 31 can be applied with confidence in environments similar to Mat of Malaysia. 2. Subgrade densities in Malaysia are commonly in excess of the maximum dry density of the British Standard 2.5 kg (5.5 lb) rammer compaction test, and subgrade moisture contents are unlikely to be more than two per cent wetter than the optimum moisture content given by this compaction test, except in very adverse drainage conditions. 3. Subgrade CBR values in Malaysia are commonly in excess of 10 per cent. 4. The use of sub-bases mder Malaysian pavements would be advantageous. 5.’ An early life deflection 60 x 10-2 -3 mm (25 X 10 in) on the 50 mm to 100 mm thick bitumen-macadam surfacings studied (overlying crushed-stone bases) indicates a life of 500 000 standard axles in the Malaysian environment. 6. Macadam-type bituminous overlays have markedly less effect in reducing pavement deflection in the Malaysian environment than denser mixes achieve in temperate climates. References 1. 2. 3. 4. 5. The operation with the Malaysian Public Works Department. It forms part of the progr~e undertaken for tie Ministry of Overseas Development, but any views expressed are not necessarily those of the Ministry. If this infwmation is insuffident for yow needs a copy of the full report, LR795, may be obtained on utitten request to the Te&nical Information md Libr~ Semites, Transport md Road Rese~ch Laboratmy, Old Wokinghm Rod, Crouthome, Berkshire. Crown Copyright. Extracts from the text may be reproduced, except for commercial purposes, provided the source is acknowledged. ROAD RESEARCH LABORATORY. A guide to the structtial design of flexible and rigid pavements for new roads. Department of the Environment, Road Note No 29. London, 1970 (HM Stationery Office) TWSPORT ~D ROAD ~SEARCH LABORATORY. A guide to the structural design of bitu- , minous-surfaced roads in tropical and sub-tropical countries. Department of the Enviro~ent, Road Note No 31. 3rd edition. London, 1977 (HM Stationery Office) . Shell 1963 Design charts for flexible pavements. London, 1965 (Shell International Petroleum Company) BRITISH STANDARDS INSTITUTION. British Standard 1377:1975. Methods of testing soils for civil engineering purposes. London, 1975 (Britis~ Standards Institution) . LISTER N W. Deflection criteria for flecible pavements. Department Gf the Environment, TRRL Report LR375. Crowthorne, 1972 (Transport and Road Research L*oratory). work described in this Digest was carried out by the Overseas Unit of TRM in co- TRANSPORT and ROAD RESEARCH LABORATORY Department of the Environment Department of Transport TRRL LABORATORY REPORT 795 PAVEMENT PERFORMANCE AND DEFLECTION STUDIES ON MALAYSIAN ROADS by J N Bulman and H R Smith The work described in this Report forms part of the programme carried out for the Ministry of Overseas Development, but any views expressed are not necessarily those of the Ministry Overseas Unit Transport and Road Research Laboratory Depatiment of the Environment Department of Transport CroWhorne, Berkshire 1977 ISSN 0305–1 293 CONTENTS Abstract Page 1 1. 2. 3. 4. 5. 6. 7. 8. htroduction DetdsoftheroadsitesStudies 2.1 hcationsofthesites 2.2 Subgraaesodsandcfimaticconditions me measurementsandtestsmaae 3.1 Thestanaaraofconstruction oftheroads 3.2 Testsonthepavementandsubgradernaterids 3.3 Deflection tests 3.4 Pavementconditionmeasurements 3.5 Trafficcounts Discussion 4.1 Theperformanceofthepvementsstudied 4.2 Thepavementdeflection characteristics tinclusions Achowledgements Wferences Appen@ 1 1 2 2 2 2 2 4 4 9 9 9 9 18 20 20 36 @ CROWNCOPYWGHT 1977 Extracts from the text my be reproduced, except for commercial purposes, provided the source is acknowledged PAVEMENT PERFORMANCE AND DEFLECTION STUDIES ON MALAYSIAN ROADS ~ttisaregivenoftheperformanceovera periodofelevenyearsof normafly-constructed roadpavementsinMalaysia.Currentpavementdesignrecommendationsarecomparedwiththethicknessandqurdity ofthepavementsstudied.hvementdeflection characteristics are relatedtoperformanceundertraffic, anddeflection-criterion curves aregivenfofroadswithcrusher-run basesandbitumen-macadam surfacings intheMalaysianenvironment.Itwasfoundthattypical Mrdaysianbituminousoverlaysreducedeflections lesthanmightbe expectedfromexperiencegainedelsewhere.Inspiteofthehighrainf~ inthecountryandthepermeablepavementconstruction employed, itwasfoundthatsubgrademoisturecontentsarerarelymorethan2 per centwetterthantheoptimummoisturecontentintheBritishStandard 2.5kgrammercompactiontestandtheyareusuafiysignificantly drier thanthis.Itisconcludedthatthepavementdesignrecommendations forflexible pavementssetoutinRoadNotes29and31canbeappfied withconfidenceinenvironmentssitiartothatofMalaysia,andthat theuseofsub-basesinMalaysiawouldbeadvantageous. 1. INTRODUCTION Theperformanceofnordy-constmctedroadpavementsinMalaysiahasbeenstudiedovera pefiodof elevenyearsandcurrentpavementdesignrecommendations havebeencomparedwiththethicknessandqtity ofthepavementsinrelation tothetrafficcarriedandsubgradestrength. Theuseofdeflection bearnslformonitoringtheconditionofroadpavementshasbecomeincreasin~y popularinrecentyears,andinseveralcountriesdeflection techniqueshavebecomeanintegral partofthe highwaymaintenanceprocess23’4. ‘ lnothers,deflection measurementsareusedforpavementdesign purposes5’6. Thedeflection characteristics oftypicalMalaysianroadpavementshavebeenstudiedtodeterminewhethertheyaredifferent fromthoseoftypicalroadpavementsintemperateclimates. Mostoftheexperienceoftheuseofdeflection techniquesinhighwayengineering hm beeniicqutied in temperatecfimatesandthepurposeoftheMalaysianstudywastoinvestigate whetheranydifferences in approacharenecessaryinhottropicalclimates.h particular, itwasdesiredtofmdoutwhethertileearlyEfetransient deflection ofaroadpavementunderastandardwheelloadcorrelated withthesubsequent ‘Efe’ofthepavementashasbeendemonstratedelsewhere 78‘ . IntheUnitedKngdom long-termstudiesof thedeflection characteristics ofroadpavementsg‘10haveenabled‘deflection criterion curves’tobederivedl1 whichprovidethehighwayengineerwithatechniqueforpredicting thefuturetraffic-carrying capacityof 1 efisting pavements.Thisisparticularly usefulfordesigningroadstrengthening measures. A co~perativeresearchprogrammewascommencedinPeninsular Malaysiain1964by theMalaysian PubficWorksDepartment(JabatanKerjaRaya)andateamfromthe~ TransportandRoadResearch hboratory.Fufl-timestudieswereundertakenintheperiod19641967,andintermittent pavement performanceandtrafficsurveys have been undertaken subsequently. Eight road sites were studied in detafl, 12,13,14 and to study 10ng- each site being used both to check current pavement design recommendations term deflection characteristics. h addition during the course of the study different methods of undertaking deflection surveyswithdeflection beamswereinvestigated 5,andseveralotherpardelstudieswereundertakenwhichhavebeenreportedseparately 16,17,18,19,20,21. 2. DETAILS OF THE ROAD SITES STUDIED 2.1 Locations of the sites Deflection andperformancestudieswerecarriedouton eight1.6km (1mfle)longsectionsofnormaUyconstructed road.Thelocations oftheroadsitesareshown in Figure 1. Where possible the sites were located on recently-constructed roads on the more heady trafficked routes in the country. Sevenoftheeightlengths of road had pavements consisting of crushed stone bases with bitumenmacadam surfacings. This is the form of construction most commonly used for main roads in Malaysia. The eighth road site had a pavement consisting of a cement-stabfised sand base with a sand-bitumen surfacing. Ttis form of construction is uncommon in Malaysia. 2.2 Subgrade soils and climatic conditions Descriptions of the subgrade sofls at each site are given in Table 1. Seven of the sites were located on hi~y-weathered granite or weathered sandstone:shde, these SOUSbeing typical of the greater part of the surface area of the Wlay peninsula. One site waslocated on a sand ridge resulting from an ancient beach line. M the sitesexperienceheavyrainfall andhightemperatures. Table2 givesrainfa~data22coUected atstationsadjacenttotheroadsites.Maximum dafiytemperatures arevirtuflyconstantthroughoutthe yearatW sites,remainingatabout32°or33°C(89°to92°F). 3. THE MEASUREMENTS AND TESTS MADE 3.1 The standard of construction of the roads During thecourseofthestudyaseriesoftestpitsandinspection holeswasdugateachroadsiteto establish thequafityandthicknessofthepavementlayers. At each site, four 50 cm by 50 cm (20 in by 20 in) test pits were dug through the pavement and measurements were made of the in-situ density of the subgrade using the sand replacement method2’3. The strength of the subgrade was also assessedat these points by means of in-situ CBRand cone penetrometer tests. The thickness of each pavement layer was noted and samples of the pavement materials and the subgrade were taken for testing in the bboratory. 2 TABLE 1 Dettisofsitesinvestigated Site No 1 2 3 4 5 6 7 8 bcation Route 1. Trolak, 60 d (96.6 km) south of Ipoh Route 2. Sungei Way new fiage 7 rrd (1 1.3 km) west of Kuala hmpur Route 2. Subang Airprt approach road 13 d (20.9 km) west of Kuala ~mpur Route 2. Batu Tiga 16 d (25.8 km) west of Kuda hmpur Route 2. Hang 19 d (30.6 km) west of Kuda kmpur Route 1. Southern Approach 6 ti (9.7 km) south of Kuda hmpur Route 1. Sungei Dua 54 d (86.9 km) south of Seremban Route 3. Kuda Rompin-fidau 94d(151.3 km) south of Kuantan Submade materials Sedimentary, varying fithological types: mostly salty shales Granitic sofl plus some sandy tin mine tatigs Weathered granite Qrboniferous shales, sandy shales and sandstone Sod derived from deeply weathered rocks, mostly shty shales with hard ferruginous gravel bands Weathered granite Sedimentary, varyingfithological types mostlysaltyshales @aternaW dune sand Pavement type Two-course bitumen-macadam surfacing on crushed granite base Two-course bitumen-macadam on crushed timestone base Singe-course bitumen-macadam on crushed hmestone base Two-course bitumen-macadam on crushed hmestone base Two-course bitumen-macadam on crushed timestone base Sin~e-course dense bitumenmacadam on crushed granite base Sin~e-course bitumen-macadam on crushed granite base Bitumen-sand mti on cementstabdised sand base Dateopened to traffic February 1965 1956 December 1964 1961 June 1964 October 1964 1962 1963 TABLE 2 Rainfddatafrommeteorological stationsadjacenttotheroadsites Station Tanjong Mrdim Kuda hmpur Port Swettenham Segamat Tampin Mersing Kajang hnual average tot~ rtinfd in. 120.6 94.9 90.6 78.4 80.4 111.1 93.8 mm. 306.4 240.9 230.2 199.1 204.2 282.2 238.1 Average range montMy totals in. 6.3–14.7 4.0–1 1.0 4.3– 9.9 4.1–10.9 4.2– 9.5 5:4–20.3 4.0–10.9 mm. 15.9–37.4 10.2–27.9 10.2–25.2 10.5–27.7 10.6–24. 1 13.8–51.6 10.2–27.7 No. ofyears ofobservations 38 69 17 33 46 32 58 Adjacent to* road sites Nos 1“ 2,3,4,6 5,4 7 7 8 6 * seeTable1forlocationofSites h additiontothetestpits,approximately tensmaflerholesweredugateachroadsiteadjacenttothe deflection test points. The same measurements of the pavement structure were made in these smder holes as in the pits, except that in-situ densities were not measured. The results of the pavement thickness investigations and the subgrade measurements are summarised in Table 3. 3.2 Tests on the pavement and subgrade materials Samples of the bituminous surfacing materials were analysed to determine the bitumen contents and the aggregate gradings. The results are given in Table 4. h addition, checks were made of the penetrations of the binder recovered from sin~e samples from each site and the results of these tests are dso included in Table 4. Samples of the crushed-stone bases were taken and their gradings were determined. A hmited number of aggregate impact tests 24 were carried out on the recovered material. The grading results and the impact test resdts are given in Table 5. Samples of the subgrade sofls were taken for moisture content tests, and the standard classification tests23 were carried out on most of the samples. Compaction tests23 were carried out on the b~ samples obtained from the larger test pits. The results of the tests on the subgrade sofls are summarised in Table 3. 3.3 Deflection tests Nflection measurements were made in both vergeside and offside wheelpaths at approximately twenty chainages on each road site over a period of eleven years. The test points were referenced to permanent markers in the road verge so that the tests could be repeated at precisely the same points in successiveyears. The standard TRRL dynamic method of making deflection beam measurements was used. This employs a 6350 kg (14,000 lb) afle load. (See Appen&x 1.) 4 TABLE 3 Pavement thickness and subgrade data* Site No. 1 2 3 4 5 6 7 8 Thickness of bituminous surfacing mm 96 (20) 110(13) 72 (17) 102 (17) 86 (17) 106 (14) 47 (16) 44 (20) Thickness of base mm (BLOCKS) (BLOCKS) 166 (20) 166 (13) 329 (17) 238 (17) 266 (17) 306 (14) 273 (16) 213 (20) Thickness of sand blanket mm o (20) o (13) 13(17) o (17) o (17) 29 (14) O(16) o (20) 1965/67 Subgrade Surface Mean in-situ CBR Per cent 19 (8) 40 (8) 31 (16) 26 (10) 23 (7) 11 (7) 6 (8) 54 (8) Range Per cent 9–32 12–90 14–48 11–42 13–30 10–12 l–lo 28 – 87 Mean moisture content Per cent 19.7 14.2 18.6 14.3 19.0 17.0 29.9 19.8 1965/67 At Depth of 150 mm Mean in-situ CBR Per cent 14 ~4) 16 (3) 30 (6) 15 (3) Range per cent 17 (5) 6 (7) 45 (3) 12–16 12–21 — 18–45 12–17 12–23 1–17 30 – 55 Mean moisture content Per cent 18.2 19.6 14.2 25.1 19.5 35.9 19.8 1971 Top 100 mm of Subgrade Mean in-situ CBR Per cent 14 (8) 14t (5) 13+(7) 17+ (9) 15+(6) 9 (8) Range Per cent 7–15+ 7–18+ — 9–18t 15–18t 12–18t 5–18 Mean moisture content Per cent 20.2 17.9 — 17.6 19.3 16.2 23.3 (CB#e~~~d tith MEXE penetroIn-situ Dry Density (1965/67) k~m3 1890 (8) 1858 (8) 1746 (8) 1938 (8) 1730 (8) 1762 (8) 1490 (8) 1698 (8) @Moisture content Per c~t 18.3 (8) 15.2 (8) 18.3 (8) 13.5 (8) 20.2 (8) 18.3 (8) 32.6 (8) 20.8 (8) Density relative to British Standard Per cent 104 102 105 104 106 103 96 105 Compaction British Standard Compaction per cent Optimum moisture content 17.4 15.3 19.7 14.5 23.0 18.3 25.9 19.3 Subgrade plasticity index Per cent o–22 17 – 30 29 – 43 O–25 15–40 16–24 9–36 O(8) TABLE 3 (continued) Site No. 1 2 3 4 5 6 7 8 Grading of Subgrade Mterial Gravel Per cent 18(11) 11(11) o (4) 3 (14) 23 (16) 5 (12) 24 (17) O(8) Sand Per cent 35(11) 51 (11) 44 (4) 43 (14) 26 (16) 44 (12) 12(17) 65 (8) Sdt Per cent } 47(11) } 58(11) 12 (4) ~ay kr cent 44 (4) } 54 (14) } 51 (16) } 51 (12) } 64 (17) } 35 (8) Average values for each site are given in the table and the number of separate measurements that were made at each site are shown in brackets Wtimum CBR measurable is 18 depending upon sofltype TABLE 4 bboratory test results of samples of bituminous surfacing materials 1 2 4 5 6 7 Binder/ Wearing* NewOverlay Binder Wearing Binder Wearin[ New Overla~Binder Wearing Binder Wearing ., in. mm. 1~ 38.1 1 25.4 a 4 19.1 $ 12.7 a 8 9.5 ~ 6.4 ~ 3.2 No. 7 2.4 No. 14 1.2 No. 25 0.6 No. 52 0.3 No. 100 0.15 No. 200 0.07 No. &mples \ 100 100 95–loo 77–92 ~ 61–81 .2 36—63 & 2 ‘- g 18—41 2 – 10–23 7–16 — 3–7 15 93–1OC — 54–82 43–63 — 22–41 — 13–28 — 8–18 7–15 — 5–9 9O–1OC 72–85 51–68 34–50 — 13–20 — 9–16 — 6–1 1 5–lo — 2–6 100 82–96 72–85 51–70 — 3144 21–32 16–25 — 9–14 7–11 — 4–7 100 97–loo 86–loo 66–81 — 3149 — 14–26 — 6–12 5–9 4–6 3_4 100 95–10( 71–89 — 33–51 — 14–27 — 6–14 5–9 — 4–8 100 74–89 48–68 — 37–56 — 2846 25–39 21–23 12–16 5–8 3–6 100 95–97 — 74–83 59 — — 32–36 21–25 — 7–9 100 91–97 — 56–71 — 3344 — 20–28 16–21 12–15 8–13 100 85–97 — 58–69 — 36–42 — 21–26 15–19 — 8–11 5 3.5–4.0 7 5 5 100 98–99 — 69–75 46–55 41 –50 — 24–32 16–22 11–16 7–lo 100 96–98 — 65–72 — 4146 28–33 21–31 14–17 10.-13 7–lo 2 1.5–4.6 52 2 0 5 2.0–4.2 — — — 6 3.1–5.0 35 4 8 6 1.3–2.9 — — — 7 2.04.5 5 4 8 4 5.0–5.5 48 4 0 7 2.4–3.9 — — — 6 3.14.0 — — — 4 4.1–5.0 35 6 2 8 3.5–5.0 13 6 9 Bitumen Content percent 2.4–4.1 Bitumen Recovery PEN 21 at 25°C No. of &mples combined 11 Age of %mpling Years 5 * 1 byer 4 ,,,,,,,.,,,,,,,, ,,, ,,, ,,, ,,, ,,, ,,, ,,, ,., ,,, ,, ,,, TABLE 5 Results of impact vahre tests and gradings of samples recovered from the crushed-stone bases SiteNo. 11 2 13141516 7 8 Base Mterid SpecificGravity A~egate ImpactValue No.ofTests Granite Gratite 19.9–28.5 2 Sand-Cement 2.75 — — 2.70–2.75 19.6–20.8 3 19.5–20.5 4 18.2–21.3 3 18.8–24.5 4 19.3–23.8 4 — — BSSieveSize II in. mm. II 100–95 90–80 75–58 63–48 36–20 28–14 100 ‘88–80 62–54 36–27 28–1 8 24–1 7 17–12 12–6 8–4 100–89” 87–74 71–55 50–30 27–15 20–1 1 13–6 9–5 7–4 100–95 89–74 72–44 50–22 30–12 23–9 16–6 124 9–3 100–95 82–75 56+8 38–29 29–23 24–1 8 13–10 1o–7 7–5 100–85 87–67 7340 55–21 39–12 29–9 17–6 124 94 100–67 76–55 56’40 40–24 29–18 23–15 14–8 104 6–3 — — — — — — — — w — 7 10 10 9 10 12 1- When deflection tests were being made the temperature of the pavement 40 mm (1.6 in) below the surface was measured with a mercury-in-~ass thermometer inserted into an ofl-ffled hole driven into the road surfacing. The measured deflection wasthen corrected to its equivalent value at 35°C by use of tempemture/deflection relationships established for the different sites asindicated in Figure 2. &ch test was repeated and if the second reading differed by more than 4 x 10-2m (2.0 x 10-3 in) from the frost, a third and sometimes a fourth test was made untfi two readings were obtained with not more than 4.x 10-2mm (2.0 x 10-3in) difference between them. Summaries of the deflections measuredateachoftheeightsitesoverelevenyearsaregivenin Table6. 3.4 Pavement condition measurements At each of the deflection test points measurements were made of the transverse deformation in the wheelpaths and the amount of cracking of the road surface each time the deflection measurements were made. The deformation in the wheelpaths wasrecorded asthe rut-depth measured beneath a ~!m (6 ft 6 in) long straight-edge laid transversely to the axis of the road. The amount of cracking at the test points was recorded as the length of visible crack per unit area. A simple rating system for recording transverse deformation and cracking was devised (as is shown in Table 7). The deformation and cracking indices were assigned numerical valuesranging from one to five. h this way an overa~ rating for each site can be obtained by adding together the values applicable to each deflection test point. These overd condition ratings are shown in Table 6. The relation between pavement condition and deflection can be plotted against traffic as a ‘deflection history’ chart. Deflection history charts were prepared for M the sites and Figures 3 and 4 show typical charts for Sites 1 and 5. Site 1 was a site with very variable structural characteristics and Site 5 is typical of the more consistent sites. Figure 5 givesthe key to the symbols used to record pavement condition in the deflection history charts. 3,5 Traffic counts tie-day (12-hour) counts of the numbers of commercial vehiclestraversing the sites were made at intervals of one or two years during the course of the study. These were supplemented by one-day and seven-day sixteen-hour counts undertaken by Jabatan Ke~a Rya (Pubfic Works Department) as part of a regular national traffic census. Using Udde’s equivalency factors 25 and the results of de load surveys undertaken in Malaysia19, the numbers of commercial veticles traversing the sites have been expressed in ‘ terms of the cumulative number of equivalent 8200kgf(18000 lb~ standard sties that have passed over the sites (in one direction) since they were f~st opened to traffic. (Table 8.) 4. DISCUSSION 4.1 The ~rformance of the pvements studied Six of the eight pavements studied required maintenance overlays afier periods ranging from six to ten years. Two of these sites (sites 1 and 4) were given bituminous overlays thick enough to add significantly to their structural value (ie greater than 50 mm), afier six years’ and ten years’ service. Site 3 received its 9 A o Site No. . TABLE 6 Summaryofthepavementconditionandthedeflections recorded (corrected for temperature) at the eight sites May 1965 20 42 40 0 118 59 T 28 28 0 41 22 Jovembe] 1964 Octobe] 1965 November 1966 ~ebruary 1967 June 1967 November 1968 Apd 1971 July 1971 20 40 40 0 88 40 Overlaid January 1973 May 1975 Date of Testing 20 45 123 5 99 52 20 41 123 0 83 37 20 42 85 0 74 35 % Overbid No. of test points Surfacecondition } $~, rating ‘c No.ofpatchedpoints Meandeflection x 10-2rnm Standarddeviationx 10-2mm tirnments 20 44 40 0 242 126 20 43 40 0 94 54 21 45 42 0 31 10 20 43 57 0 97 54 20 46 58 0 106 52 20 54 90 0 98 49 1 14 28 28 0 40 17 14 30 28 0 45 22 14 29 33 0 45 19 14 29 31 4* 51 28 *Overbid 14 29 34 10* 43 25 *Overlaic No. of test points Surface condition } ‘~, rating ‘c No. of patched points Mean deflection x 10-2mm Standard deviation x 10-2mm @mments 14 29 28 0 50 21 2 Re-rdigned 21 43 48 0 31 9 21 42 42 0 30 10 1w WRG’ Course No.of test points } Surfacecondition ‘D’ rating 6> c No.ofpatchedpoints Meandeflection x 10-2mm Standarddeviationx 10-2mrn timments 21 42 42 0 46 17 21 42 42 0 20 9 21 47 42 0 28 9 21 43 42 0 32 7 21 42 47 0 36 7 3 4 ,,, ., 20 40 40 0 55 14 Overlaid 20 40 41 0 50 11 20 41 41 0 34 11 20 70 40 0 48 17 20 68 40 2 64 16 20 39 34 13 65 16 Patching No. of test points Surface condition } ‘D, rating <3 c No. of patched points Mean deflection x 10-2mm Standard deviation x 10-2mm timments 20 53 40 0 55 23 20 54 40 0 ,49 19 20 57 40 0 50 17 . . TABLE 6 (continued) ,— Site No. 5 6 Date of Testing Novembe 1964 May Octobe] 1965 1965 22 42 36 8 42 29 16 32 32 0 69 22 20 45 40 0 64 35 28 — — o ~~ 14 November 1966 Februaq 1967 June November 1967 1968 Apd I July 1971 1971 January 1973 May 1975 20+ 41 111 O* 28 10 *Resurfaced June No. oftestpoints } Surfacecondition ‘U rating ‘c No.ofpatchedpoints Meandeflection x 10-2mm Standarddeviationx 10-2mm timments 22 51 46 0 49 22 45 22 22 45 50 52 48 2 * 37 36 17 14 *Remainde Overlaid 22 50 56 0 33 17 22 46 86 0 36 14 16 34 48 0 57 20 44 * 32 17 Part *Overlaid 34 No. of test points Surface condition ‘~ rating } ‘c No. of patched points Mean deflection x 10-2mrn Standard deviation x 10-2mm timments 16 23 32 0 75 27 16 35 31 1 64 24 16 16 36 30 48 41 1 9 63 68 20 21 16 34 36 0 67 14 ~verkid 14t 29 45 0 51 22 No. oftestpoints } Surface condition ‘D rating ‘c No. of patched points Mean deflection x 102mm Standard deviation x 10-2mm bmrnents 20 44 “40 o 80 35 20 49 42 0 76 56 20 20 48 50 42 47 0 0 84 73 56 41 20 48 63 0 98 70 20 48 62 * 82 43 ~1AOverlaid Overlaid No. of test points } Surface condition ‘D’ rating ‘c No. of patched points Mearl -2 de?lecP,er,x 10 w,rn Standard deviation x 10-2mm timments 28 56 64 0 ~? 9 28 56 74 0 46 16 28 56 83 0 As 18 28 56 87 0 56 29 28 62 92 0 6A 30 28 58 114 0 78 29 Overlaid t 2 points lost due to reconstruction work Note. A surface condition rating of greater than 4 x (No. of test points per site) for either cracking or deformation indicates that the pavement is in a critical condition TABLE 7 ~assification of road surface condition Transverse deformation under a 2m (6.5ft) lC ~assification hdex D2 D3 D4 (regarded as ‘fafle& in ~) D5 (suggested faflure criteria for main roads in Wlaysia) ;straight-edge Deformation hSS than 10mm (3/8in) 10mm (3/8in) to 1Sm (9/16in) 15mm (9/16in)to 20mm(13/16in) 20mm(13/16in) to 25mm(lin) Greater than 25mrn (1 in) Degree of cracking (visible cracks) —.. ~assification Index cl C2 C3 C4 C5 CrackIength/unit area Nfl Notgreater than lm/m2 Greater than 1m/m2 but not greater than 2m/m2 Greater than 2m/m2 but not greater than 5m/m2 Greater than 5m/m2 (ravetig & pothotig imminent, immediate maintenance required) 12 Site 1 2 3 4 5 %te of Opening of Road October 1964 1956 1 December 1964 1961 June 1964 TABLE 8 fitimated cumdative number of standard sties that have traversed the sites (in one direction) Date of kflection Test NOV 64 Apr 65 NOV 65 Feb 67 my 67 NOV 6% Mr71 Jan73 DC 64 June 65 Nov 66 June 67 .Oct68 Apr 71 Jan 73 Dec 64 Aug 65 Feb 67 June 67 Ott 68 Apr 71 Jan 73 Dec 64 June 65 Nov 66 July 67 Ott 68 Apr71 - Jan 73 WC 64 ‘-June65 Nov 66 July 67 Nov 68 Apr 71 Jan 73 ~st.of tire. No. of CVSsince openingof road (x 106) 0.01 0.05 0.09 0.24 0.27 0.46 0.81 1.20 2.82 3.07 3.89 4.18 5.05 6.87 8.50 0.00 0.03 0.11 0.18 0.22 0.43 0.67 1.42 1.67 . — 2.46 2.75 3.54 5.39 6.97 0.23 0.47 1.18 1.57 2.33 4.60 6.18 fit. of tire. No. of Std. Mes since opening of road (x 106) <0.01 0.02 0.04 0.10 0.11 0.19 0.33 0.49 1.16 1.26 1.59 1.71 2.07 2.82 3.49 0.00 0.01 0.05 0.07 0.09 0.18 0.27 0.58 0.68 1.01 1.13 1.45 2.21 2.86 0.09 0.19 0.48 0.64 0.96 1.89 2.53 13 TABLE 8 (continued) Site 6 7 8 DateofOpening ofRoad October 1964 1962 1963 Dateof Deflection Tc NOV64 May 65 Jan67 July67 Nov68 Apr71 Jan74 Jan 65 July 65 Jan 67 my 67 Nov 68 Apr71 Jan 73 Jan 65 Jul 65 &t 66 Mar 67 Nov 68 Apr71 Jan 73 Est. of tire. No. of Ws sin openingofroad(x106) 0.03 0.11 0.27 0.50 0.87 1.81 2.67 0.13 0.17 0.28 0.29 0.43 0.68 0.91 < 0.01 0.01 0.09 0.10 0.18 0.27 0.37 Est. of Cum. No. of Std. Mes since opening of road (x 106) 0.01 0.05 0.11 0.21 0.36 0.74 1.09 0.05 0.06 0.11 0.12 0.18 0.28 0.37 <0.01 <0.01 0.04 0.04 0.07 0.11 0.15 14 ffist wearing course after approximately eight years’ service, but it is tightly trafficked. Site 8 was overlaid after approximately thirteen years. This is typical of the performance of most of the new main road construction undertaken in western Mlaysia in the nineteen sixties and compares favorably with.the service fives achieved with flexible road surfacings in other tropicrd countries. ~ the pavements can be said to have performed satisfactory in that they have carried the traffic loads imposed on them for more than ten yetis without suffering significant structural faflure and the two pavements that received substantial overlays had thinner pavements in relation to traffic and subgrade strength than is recommended in any widely-used pavement design guide. However, when the amount of traffic traversing the sites istaken into consideration, big differences can be distinguished between the relative performance of the different pavements and the durabtity of the surfacings proves to be considerably less than would be expected of hot-mix bituminous surfacings in Britain. It is useful to examine the reasons for these differences in performance. Thetotal pavementhicknessoftheeightroadsitesarebroadysimflartotherecommendationsgiven bytheTransportandRoadResearchtiboratory12~13,andtheSheUDesignCharts14fora fifteenyeardesign fifeatthetrafficlevelsexperienced. Table9 comparesthepavementhicknessmeasuredatthesiteswiththese recommendations. Precisecomparisonsmay bemisleadngbecauseofthediffering criteria forpavement faflurethatareimphcitbothinthedifferent pavementdesignmethodsandinnormalhighwayen@eering practicein~aysia. Forexample,inWlaysiacrackingofbituminoussurfacings isthecommonestform offtiure(seeTable6)andhighdegreesofcrackingaretolerated beforeoverlaying, wtistinBritain deformationismuch moresignificant asamode offaflureofbitutioussurfacedroads.Nevertheless, wtist precisecomparisonsbetweentheperformanceoftheWlaysianpavementsandthepavementdesi[precommendationsshouldnotbemade,generalcomparisonsareuseful.Generdyspeakingthethicknessofbituminous surfacing andbasefoundatthestudysiteswasequalto,orgreaterthanthatwhichisrecommended,butwhen theabsenceofthesub-baseistakenintoaccounthetotalthicknessofpavementprovidedisofmuch the sameorderasisrecommended,exceptperhapsforsites1and4 whicharesignificantly thinner.Theeffect ofthepracticeofomittingsub-basesin~laysiaisthustousehighquatitycrushedstonemateriallower downinthepavementstructure thanisnormallyfeltnecessaryelsewhere.Thefacthatsubgradestrengths arerelatively highwouldfavourtheuseofsub-basessincematerialtsub-baselevelisrelatively fi[~tlystressedon strongsubgrades.ltwould,therefore, appearthateconomiescouldbemadeifcheaperlowergradematerials wereusedforsub-basesinplaceofthelowerpartofthecrushedstonebase.Possible materials forsubbasescouldbedecomposedrockandquarryoverburden, thesandproducedasawaste productinthetinminingindustry, lateritic gravels, andpossiblyimestabfisedsofl. Since the differences in pavement performance between the sites cannot be attributed primady to differences in pavement thickness in relation to the traffic and subgrade strength, it is Mely that differences in the qufity of the pavement materials are responsible. Examination of the bituminous surfacing analyses (Table 4) and the grading results of the crushed stone bases (Table 5) indicates that there are large differences between sites in the qualities of the surfacing materials, but that the base materials, although poorly graded, are much the same on afl sites. This is supported by visual observations of the quality of the surfacings whichrangefromfineclose-textured bitumenmacadamon somesites(sites2,6andpartof 5)toverycoarseopen-textured macadamsonothers(1,4,7andpartof5).Itisnotablethatthesites withthedensersurfacings haveperformedbetter(atmuch heaviertraffic levels)thanthosewiththecoarse open-textured surfacings. Itwasdsoobservedthatdensification ofthesurfacings inthewheeltrackswas common,evenwiththeclose-textured mixes.~st thisistobeexpectedtosomeextentwithmixesof 15 t — + — t — t — ****+ this type, it is dso Wely that the degree of initial compaction is sometimes deficient, probably as a restit of the laying temperature being too low. men diggingthe test pits it was found that adhesion between the bitutious layers and between the surfacing and the base was very low or non-existent, and water was frequently found between layers. This indicates the high degree of permeabfity of the surfacings, one consequence of which is the rate at which the binder hardens. Table 4 shows that the binder in the older open-textured surfacings was found to be very hard, wtist the binder of the denser mixes on sites 2 and 6 had hardened much less. Thusthe evidence is that the overti performance of sites 1 to 7 wotid have been much improved if they had been sealed by surface dressings or surfaced with higher qufity dense bituminous surfacings. Such mixes require the avdabfity of plentiful supplies of non-plastic sand-sized material. This could be reatiy obtained in many parts of Malaysiaby washing and screening the tin-mining waste that occurs widely. The performance of site 8, which has a cement-stabfised base and a bitumen-sand surfacing, must be mnsidered separately from the other seven sites since its mode of deterioration, block-cracking, is different from the cracking (accomptied by deformation) that occurs in the crushed stone bases. Transverse cracks at re~ar spacings appeared in the surfacing of this road soon after it was constructed. This is a very mmmon feature in roads of this type and it need not necessarily give any cause for concern if the pavement is buflt on a freely draining sand subgrade such as exists at site 8. It has been shown that given reasonably adequate curing, the spacing, and hence to a large extent the size, of these characteristic transverse cracks is governed dy by the tensfle strength of the stabfised sofl at the time when the pavement is ftit trafficked26 At site 8 after the transverse cracks had first appeared, there was very fittle further kcrease in cracking and virtuafly no transverse deformation for several years (see Table 6). After about four years’ service however, the amount of cracking began to grow slowly under the traffic and after nine years it reached the stage where strengthening of the pavement was required. Figure 6 shows the extent of cracking adjacent to six of the deflection test points after four years of trafficking, and Figure 7 shows the crack arrangement six years later. h relation to its thickness, the subgrade strength, and the amount of traffic carried, this pavement performed less we~ than pavement design recommendations would indicate. This may have been partly due to the brittle sand-bitumen surfacing that reatiy reflected cracks in the base and which wore aw~y in the wheel tracks untfl the base was exposed. Neverthelessthe growth in cracking that occurred at rekitively low values of traffic was unexpected and may have been due to unrecorded heavy traffic using th(; road for certain periods when timber was being extracted from new areas served by the road. An examinationoftheresultsofthetestsmadeonthesubgradesoilsunderlyingdltheroadsites (seeTable3)showsthatforsevenoftheeightsitesthesubgradedensities were equal to or higher than the British Standard maximum dry density in the 2.5 kg (5.5 lb) rammer compaction test23. Since dl but one of the sites were relatively recently constructed at the time when the in-situ subgrade density measurements were made, it is u~ely that traffic compaction would have contributed very much to the density of the subgrades. Hence it can be concluded that it is reasonable to base pavement designsin Malaysia on the strength of the subgrade sofl assessedat the British Standard 2.5 kg rammer test maximum dry density. 17 tie hundred and ninety measurements of the subgrade moisture content were made under the pavements at 73 different chainages (the results are summarised in Table 3). More than half,of these moisture mntents were equal to or drier than the optimum moisture content (OMC) of the subgrade soflin the British Standard 2.5 kg (5.5 lb) rammer compaction test, and three-quarters of them were drier than the OMCplus 2 per cent. The ody places where subgr2de moisture contents were wetter than this were where gross drainage deficiencies were apparent and free water was aflowed to coflect in the road bed. The subgrade drainage characteristics of the eight sites were representative of the great majority of roads in Penninsdar Waysia; hence it can be concluded that if reasonable provision is made to drain off any water that may coflect at subgrade level, pavement designsfor most road situations in Makysia can be based on a subgrade strength assessedat the optimum moisture content in the British Standard compaction test plus 2 per cent. Ody when high water tables occur need higher subgrade moisture contents be assumed. It should be noted from Table 3 that virtudy aflthe in-situ subgrade CBR’Sthat were measured were greater than CBR 10, and most were greater than CBR 15. Ordy on site 7, which had two very poorly drained areas, were significantly lower subgrade CBR’Sencountered. 4.2 The pavement deflection charaderistics From the beginning of the study it wasthe intention to trace the deflection characteristics of the pavements, so asto bufld up deflection histories which could be related to the pavement performance. Desirably, deflection measurements and performance ratings would have been made on aflthe sites from the time when they were fust constructed, so that the effect of the magnitude of the ‘standard early fife deflections,11 on the subsequent performance history of the pavement could be traced. The ‘standard early life deflection’ of a point on the road is defined by tister in his stuties in the United Kngdom as being the mean of up to five springtime deflection measurements made early in the tife of a road, each measurement being corrected to a standard temperature of 20°C. (In the United ~gdom roads are weakest in.the spring.) Deflections measured during the compaction phase of the road pavement, which normally occurs over the first 12 ta 18 months of trafficking, are not included in this average. h Waysia it was not possible to adopt precisely the same standard early fife deflection because: i)thestandardtemperatureadoptedwas35°C ii)thetimescaleofthestudywasshorteranditwasnecessarytoestabfish areferencedeflection overa periodofnotmuchlongerthanayear.TypicWythreeorfourdeflection measurementstakenatapproximately fourmonthintervrds wereaveragedtogivetherequiredreference, deflection. Furthermore it was considered appropriate in Malaysiato include deflections measured during the mmpaction phase since on some sites these were much higher than would norm~y be found in the United Hngdom, and they persisted at a high levellong enough to affect the subsequent fife of the bituminous surfacing. Because of the differences between the early fife deflections as determined in the United ~gdom studies and those adopted in Malaysiathe term ‘standard reference deflection’ has been used in the Malaysian studies. When the study was started in Mrdaysia,it was not possible to find many completely new pavements and some of the sites were selected on lengths of road that were two or three years old, and in one case on a road eight years old. By combining the results from sites with the same type of construction, it has been possible to derive a deflection criterion curve of the type produced by fisterl 1 for bitumen macadam surfacings on crushed stone bases in the Malaysian environment. It was not possible, however, to use the 18 twooldest sites for this purpose (sites 2 and 4) because their previous performance history was too uncertain. %ghtly different curves were obtained for the vergeside and offside wheel tracks, a somewhat lower standard reference deflection being required in the vergeside wheel track than in the offside wheel track to ensure the same pavement tife (see Figures 8 and 9). me reason for this is probably that moisture content changes in the subgrade and shoulder, contribute to pavement deterioration more stron~y at the edges of the road than near the centre. It W beseenfromFigures8and9 thatthecriterion curvesareplottedody toatrafficlevelof 400000equivalent standardafles(inonedirection). Itwouldhavebeendesirable tohavecontinuedthe performancestudiestohigherlevelsofcumulativetrafficbut400000 standardtiesrepresenteightyears oftrafficking atthesitesconcerned,whichwasthelongestperiodavailable beforemaintenance; programmed requiredthesitestobeoverlaid. kvementtemperatures prevtinginMalaysianecessitated theadoptionofahigherstandardtemperaturefordeflection measurementsthanisusedinBritain. ~though the Malaysian pavement temperatures rarely exceed 50°C, they are dso rarely lessthan 30°C in dayfight hours. It was found convenient to adopt a standard temperature of 35°C to which deflections measured at other temperatures were corrected using temperature/deflection relationships of the type shown in Figure 2. It was found that below 32°C, the stiffness of the pavement increased significantly more per degree drop in temperature than above 32°C, but because of the difficulty in establishing a clear rehtionship at these low temperatures (for Waysia), it is recommended that deflection surveys are ody carried out when the pavement temperature is greater than 32°C. In many countrieswitha markedseasonalvariation inctimate,itisnecessa~whenstudyingthe deflection historyofaroad,totakeaccountofthechangeh strengthofthepavementhatoccursasa resultofseasonalmoisturechangesinthesubgrade.On noneofthesitesstudiedinMalaysiahowever, wasanyseasonalvariation indeflection characteristics detected.~us “becauseoftherelatively uniform distribution ofrainfdthroughouttheyearthatisexperienced onthewestcoastsites,andontheeast mastsite(site8)wheredistinct wetanddryseasonsareexperienced, thestrengthofthesandsubgrade wasinsensitive tomoisturecontentchanges. It was not possible to develop a deflection criterion curve for the sand-cement pavement (site 8) because the early deflection history of this site was unknown, and its deflection characteristics were probably more influenced in the beginning by the regularly spaced shrinkage cracking, rather than by traffic-induced cracking. k Figure 10, the deflection curves derived from the Malaysian sites are shown together with some derived in the United Mngdom for roughly sitiar types of construction. Direct comparisons lsannot be made because of the different pavement assessment procedures, the different modes of faflure, the different cfimates and the different standard temperatures to which deflections are referenced. Nevertheless the much lower curve for the Malaysian bitumen macadam surfacings must partly reflect the lC)Wfatigue hfe of these materials in the ~aysian climate, susceptible asthey are to weathering of the binder. It is probable that much longer surfacing fife, and hence pavement life, could be achieved in Malaysiaif denser 27 yet more flexible mixes of the gapgraded type were used. Modified hot ro~ed asphalt , such as has been used successfully in %uth Mrica 28,29 , would be a very suitable mix to use for road surfacings in Malaysia. 19 Sites 1 and4 wereoverlaidwithsubstantial thicknesses ofbituminouspremix(varyingbetween40 mm and125mm thick)duringthelaterstagesofthestudy.Deflection surveyswereundertaken~ediately beforeoverlaying andthreemonthsafterwards, todeterminetheeffectoftheoverlaysinreducingthe deflectionsfthepavements.Figures11and12showtheresultsobtained.On site1,veryscattered resdtswereobtained,noreductionideflection beingmeasuredatmany points.Thismay havebeendue toinadequatecompactionoftherelatively thickoverlaylaidatthisiteandtononelasticdeformationf theoverkyduringsubsequentdeflection measurements.Deflection measurementsmadeoveralonger periodoftimeaftertheoverlaywaslaid,wouldprobablyexhibitlessscatterduetothecompactiveeffect ofthetrafficandthehardeningofthebitumenintheoverlay.Theoverlayon Site4 producedlessscattered deflection results, butinbothcases,itisapparentthattheoverlayshadmuch lesseffectinreducingdeflections thanhotro~edasphaltoverlaysdoinBritain30. ~s isclearlyduetothehighertemperatures t@t prevafi inWaysia andthetypeofoverlaymaterials thatwereused. 5. CONCLUSIONS The fo~owing conclusions can be drawn from this investigation: 1. 2, 3. 4. 5. 6. tirent pavement design recommendations for flexible pavements set out in Road Notes 29 and 31 can be appfied with confidence in environments sitiar to that of Malaysia, and it is probable that the application of the Road Note 29 recommendations would result in some degree of over-design, given the difference that exists between the definitions of ‘pavement faflure’ in ~ and Malaysia. Subgrade densities in Malaysiaare commody in excess of the maximum dry density of the British Standard 2.5 kg (5.5 lb) rammer compaction test, and subgrade moisture contents are ufikely to be more than two per cent wetter than the optimum moisture content given by this compaction test, except in very adverse drainage conditions.’ Subgrade CBRvalues in Malaysiaare comordy in excess of 10 per cent. The use of sub-bases under Malaysian pavements wodd be advantageous. A early fife deflection 60x 10-2rnm (25 x 10-3in) on the 50 mm to 100 mm thick bitumen-macadam surfacings studied (overlying crushed-stone bases) indicates a fife of 500000 standard afles in the Waysian environment. Macadam-type bituminous overhys have markedly less effect in reducing pavement deflection in the Maysian environment than denser mixes achieve in temperate chmates. 6. ACKNOWLEDGEMENTS The work described in this report was carried out by the OverseasUnit of TRRL. The authors are indebted to the Malaysian Director-General of Public Works, Tan Sri Mahfoz bin Wfid, and his predecessors, who gavetheir invrduable support to the study. Thanks are also due to the many members of the Wbhc Works Department staff who cooperated in this investigation. 20 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 7. REFERENCES ~GHWAY RESEARCH BOARD. The WASHORoad Test. Part 1. Design, construction and testing procedures. Highwy Research Board Spectil Report No 18. Washington, DC 1953 (National Research @uncfl). MORGAN,J R and A J SCALA. Deflections in flexible pavements. Journal of the Australian Road Research Board. Vol 2, No 5 September, 1965. Australian Road Research Board, Melbourne, 1965. DEHLEN, G L An investigation of flexure cractig on a major highway. Boc. lnt. Gn$ Stictural Design Asphalt Pavements, Ann Arbor, USA, 1962. Ann Arbor, 1963 (University of Michigan). MILLARD, R Sand N W LISTER The assessment of maintenance needs for road pavements. Roe. Znstn. Civ. Engrs, 1971,48 (Feb), 223–244. CANADIAN GOOD ROADS ASSOCIATION. A guide to the structural design of flexible and rigid pavements in Gnada. Gnadian Good Roads Association Pavement Design and Evaluation Committee. Ottawa, 1965 (Gnadian Good Roads Association). BEATON, J L, E ZUBE and R FORSYTH. Field apphcation of the resfience design procedure for flexible pavements. fioc. 2nd Znt. &nj Structural Design of Asphalt Pavements, Ann Arbor, USA, 1967. Ann Arbor, 1968 (University of Michigan). ~GHWAY wSEARCH BOARD: The AASHO Road Test. Report 7. SU~W Report. Highwy Research Board Special Report No 61 G, Washington, DC, 1962 (National Research Councfl). HVEEM,F N. Pavement deflections and fatigue fdures. Highway Resmrch Board Bulletin No 114. Washington, DC, 1955 (Highway Research Board). LEE, A R and D CRONEY. British fu~-scale pavement design experiments. fioc. Znt. Conf Structural Design of Asphalt Pavements, Ann Arbor, USA, 1962. Ann Arbor, 1963 (University of Michigan). SALT, G F. Recent fufl-scde flexible pavement design experiments in Britah. Roe. 2nd Znt. Conf Structural Design of Asphalt Pavements, Ann Arbor, USA, 1967. Ann Arbor, 1968 (University of Mchigan). USTER, N W. Deflection criteria for flexible pavements. Department of the Environment, TML Report LR 375. Crowthorne, 1972 (Transport and Road Research hboratory). ROAD RESEARCH LABORATORY. A guide to the structural design of flexible and rigid pavements for new roads. Deprtment of the Environment, Road Note No 29. bndon, 1970 (H M Stationery Office). TRANSPORT AND ROAD RESEARCH LABORATORY. A guide to the structural design of bituminous-surfaced roads in tropical and sub-tropical countries. Department of the Environment, Road Note No 31. 3rd edition. hndon, 1977 (H M Stationery Office). 21 14. SheU1963 Design Charts for Hexible Pavements. hndon, 1965 (Shefl International Petroleum Company). 15. SMJTH,HR. A deflection survey technique for pavement evrduation in developing countries. Department of the Environment, TML Report LR 525. Crowthorne, 1973 (Transport and Road Research bboratory). 16. B~MAN, J N and H R SMITH. A fufl-scaJepavement-design experiment h MaJaysia– construction and fust four years’ performance. Department of the Environment, TRRL Report LR 507. Crowthorne, 1972 (Transport and Road Research hboratory). 17. BULMAN,J N. A survey of road cuttings in Western MaJaysia. Presented at the Southeast Asian Re#onaJ Conference on Sod Engineering 2&29 ApriJ 1967, Bangkok. 18. BULMAN,J N. hvestigations into roadbuflting practice in the tropics: a study of the compction of earthworks at the new international airport for Kuda Lumpur, Malaysia. Ministry of ~ansport, RRL ReportLR115, Crowthorne, 1967 (Road Research Laboratory). 19. ELLIS, C I. Me-1oad distribution on roads overseas. Survey on roads in West MaJaysia1967. Ministry of Dansport, RRL Report LR 187, Crowthome, 1968 (Road Research Laboratory). 20. LAWRANCE,C J. Terrain evaluation in West Waysia. Part I. Terrain classification and survey methods. Department of the Environment, TRRL Report LR 506, Crowthorne, 1972 (Transport and Road Research Laboratory). 21. BEAVEN,P J, C J LAWRANCEand D NEWILL A study of terrain evaluation in West MaJaysia for road lo~tion and design. Presented to the Fourth Asian RegionaJConference on Sofl Mechanics and Foundation Engineering July, 1971, Bangkok, Thafland. 22. MALAYSIANMETEOROLOGICAL.SERVICE. MonthJy abstracts of Meteorological Observations. Kuala Lumpur. (Malaysian Meteorological Service). 23. BMTISH STANDARDSINSTITUTION. British Standard 1377:1975. Methods of testing soflsfor citi engineering purposes. hndon, 1975 (British Standards Institution). 24. B~TISH STANDARDS INSTITUTION. British Standard812: 1960. Methods for sampJing and testing of mineral aggregates, sands and fflers. hndon, 1967 (British Standards Institution). 25. HDDLE, WJ. Apphcation of AASHO Road Test results to the design of fletible pavement structures. hoc. Int. &nJ on Structural Design of Asphalt Pavements, Ann Arbor, USA, 1962, Ann Arbor, 1963 (University of Michigan). 26. BOFINGER, HE. The behaviour of sofl-cement pavements with special referenw to the problem of cracking. tioc. 4th Asian Regional Conference on Soil Mecknics and Foun&tion Engineering, Bangkok, Thadand, 1971. 22 27. BNTISH STANDARDSINSTITUTION. British Standard 594:1973. Rofled asphalt (hot process) for roads and other paved areas. bndon, 1973 (British Standards Institution). 28. HUGO,F. A critical review of asp~t paving mixes in current use with proposals for a new mix. 1st Onf on Asphalt Pavements for Southern Africa. Pretoria, 1969 (National Institute for Road Research). 29. GROTH, P J. Overlay design. 1st Conf on Asphalt Pavements for Southern Africa. Prt:toria, 1969 (National Institute for Road Research). 30. LISTER, N W. Deflection criteria for flexible pavements and the design of overlays. Boc. ~ird Int. &nfi on the Structural Desi@ of Asphalt Pavements, held in London, 1972. Ann Arbor,1972 (University ofMchigan). 23 100 102 104 F . 3 CHINA SEA I Penang . . SINGAPORE ‘~ ‘i’e o 100 200 300 km Fi~ 1 TRUNK ROADS AND TEST SITE LOCATIONS IN WEST MALAYSIA I 360, p 340 - 32o 300 - 28o ~ 14 130 120 m: I I x 140. - j .=5 u 120 - =~ s 100 - 80 - 60 - 50[- 40 * 30, - 20 - -’ o I o 0 sectionon full ~caje experiment (I 6) 40 o 0 0 9 6 Site7 I 0- /: n ● u ● ., Sjte4 <4 0 I 4“ o~ I 25 1 I 30 35 40: ,J 45 Surfacing temperature (OC) 50 I I I I I I Fig. 2 TEMPERATURE/DEFLECTION RELATIONSHIPS x 190 170 150 130 110 90 70 50 30 10 180 130 80 70 60 w: x 50 c = 40 30 20 10 0 I 1 “ 1 I I 1 I I I 1 1963 .1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 I 1 1 1 1 1 1 1 I 0 0.020.04 0.100.11 0.19 0.33 0.49 Cumulative standard axles (x 106) 00.050.09 0.240.27 0.46 0.81 1.20 Cumulative commercial vehicles (x 106 ) Fig 3 DEFLECTION HISTORY CHART FOR SITE 1 10 t 60 50 40 30 20 10 0 2 \ 02 2 2 2 3 3 43 9 4 I I I 1 1 1 I I I I 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1 I I I I I I 0.09 0.19 0.48 0.64 0.96 1.89 2.53 Cumulative standard axles (x 106) 1 1 1 1 1 I I 0.23 0.47 1.18 1:57 2.33 4.60 6.18 Cumulative commercial vehicles (x 106 ) Fig 4 DEFLECTION HISTORY CHART FOR SITE 5 “ CRITICAL FAILED 1 2 3 4 5 P D 1 0 ● ❑ ❑ m 2 0 e ❑ ❑ ■ 3 ● ● ❑ ❑ ■ 4 ❑ ❑ ❑ ❑ ■ 5 ■ ❑ ■ ❑ ■ P ❑ IC – Cracking D – Deformation P – Patching Fig 5 SYMBOLS USED FOR RECORDING PAVEMENT CONDITION ON DEFLECTION HISTORY CHARTS (Fi@ 3 and 4) 1+% 00 L f ( x ( ( x- - . . . J . ( x: ( x1 - , b x- ‘–; -.. . . . ‘( . I L , o 0 0 11 I 1 I 1 I t 1 I 111111,1,11111 1 1 1 1 1 1 11111 1 1 1 1 1 I 1 o 0 00 0. 11111 1 1 1 I I 1,,,,1,,,,1, 1 1 1 11111 1 I f I 1 I I (~-o1 x u!) 80 60 40 30 20 10 200 180 160 140 120 100 80 60 40 30 20 — Offside wheel track \ \“ \ \ Alconbury Hill (29) Verge side wheel track \ \ \ \ Boroughbridge (29) Alconbury Hill { 100mm bitumen macadam on wet mix slag Boroughbridge { 100mm hot rolled asphalt on crushed limestone on sand (C.B. R. > 15) I 1 I I -- 0.02 0.05 0.10 0.5 1.0 5.0 Cumulative standard axles (x 106 ) Fig. 10 COMPARISON OF SOME DEFLECTION CRITERIA CURVES DEVELOPED IN THE UNITED KlNG90M/W!TH THOSE FROM F!VE SITES !N WEST MALAYSIA ““ 70 60 50 40 30 20 10 180 160 - 140 120 - 100 - 80 - 60 - Overlay thickness o 0- 50mm 0 50- 75mm A 75- 100mm A 100- 125mm o 0 00 ● % 40 - 20 40 60 80 100 120 140 160 180 (mmx 10-2) 1 1 1 I I I I 10 20 30 40 50 60 70 Deflection before overlay (in x 10 ‘3) Fig. 11 SITE 1 REDUCTION IN DEFLECTION ACHIEVED BY ADDING AN OVERLAY 30 2C 10 90 80 70 60 50 40 30 20 / o ● ● A A A -- 62-75mrn / A 20 30 40 50 60 70 80 90 (mm x 10-2) 10 20 30 Deflection before overlay (in x 10-3) Fig. 12 SITE 4 REDUCTION IN DEFLECTION ACHIEVED BY ADDING AN OVERLAY 8. APPENDIX 1 STANDARD TRANSPORT AND ROAD RESEARCH LABOWTORY METHODOF MKING DEFLECTION BEAMMEASUREMENTS 1. had a 5-ton lorry (or simflar) fitted with twin rear wheels to give a load of 6350 kg (14 000 lb) on the rear afle (ie 3175 kg or 7000 lb on each pair of twin rear wheels). 2. hflatethe rear tyres to 585 kN/m2 (85 lb/sq in). Recommended tyre size 7.50x 20 with spacing of 45 mm (1%inches) between the dud wheels. 3. Mark a pointon the road at which the deflection is to be measured, and position the lorry so that the rear wheels are 1%m (4 ft) behind the marked point. 4. hsert the deflection beam between the twin rear wheels untfl its measuring shoe rests on the marked pint on the road. If required insert a second beam in a simflar way between the other pair of twin rear wheels. 5. It is helpful in positioning the lorry and aligning the beams paraflelto the lorry axis if a pointer is fixed to the lorry 1%m (4 ft) in front of each pair of twin rear wheels. 6. ~eck the beam pivot arms for free movement, adjust the footscrews if necessary, and zero the did gaugesw~st gently tapp~g the frame of the beam. 7. Record the did gauge reading. (Either zero or some small positive or negative reading.) 8. ~st the lorry is driven slowly forward to a point at least 3 m (1Oft) in front of the shoes of the beams, the frame of the beam should be tapped gently and the maximum and find did gauge readings noted. Qre must be taken to ensure that a wheel does not touch a beam. 9. For each beam calculate the transient deflection of the road surface by adding the difference between the first and maximum did gauge readings to the difference between the maximum and fmd did gauge readings. 36 (1574) Dd443233 1,500 9/77 HPLtd So’ton G1915 PRINTED IN ENGLMD ABSTRACT Pavement performance anddeflection studies on Malaysian roads: JNBULMANand HRSMITH: Department of the Environment Department of Transport, TRRL Laboratory Report 795: Crowthorne, 1977 (Transport and Road Research Laboratory). Details are given of the performance over a period of eleven years of normally-constructed road pavements in Malaysia. Current pavementdesign recommendations are compared with the thickness and quality of the pavements studied. Pavement deflection characteristics are related to performance under traffic, and deflection-criterion curves are given for roads with crusher-run bases and bitumenmacadam surfacings in the Malaysian environment. It was found that typical Malaysian bituminous overlays reduced deflections less than might be expected from experience gained elsewhere. In spite of the high rainfall in the country and the permeable pavement construction employed, it was found that subgrade moisture contents are rarely more than 2 per cent wetter than the optimum moisture content in the British Standard 2.5 kg rammer compaction test and they are usually significantly drier than this. It is concluded that the pavement design recommendations for flexible pavements set out in Road Notes 29 and 31 can be applied with confidence in environments similar to that of Malaysia, and that the use of sub-bases in Malaysia would be advantageous. ISSN 0305–1 293 ABSTRACT Pavement performance and deflection studies on Malaysian roads: J N BULMAN and H R SMITH: Department of the Environment Department of Transport, TRRL Laboratory Report 795: Crowthorne, 1977 (Transport and Road Research Laboratory). Details are given of the performance over a period of eleven years of normally-constructed road pavements in Malaysia. Current pavementdesign recommendations are compared with the thickness and quality of the pavements studied. Pavement deflection characteristics are related to performance under traffic, and deflection-criterion curves are given for roads with crusher-run bases and bitumenmacadam surfacings in the Malaysian environment. It was found that typical Malaysian bituminous overlays reduced deflections less than might be expected from experience gained elsewhere. In spite of the high rainfall in the country and the permeable pavement construction employed, it was found that subgrade moisture contents are rarely more than 2 per cent wetter than the optimum moisture content in the British Standard 2.5 kg rammer compaction test and they are usually significantly drier than this. It is concluded that the pavement design recommendations for flexible pavements set out in Road Notes 29 and 31 can be applied with confidence in environments similar to that of Malaysia, and that the use of sub-bases in Malaysia would be advantageous. ISSN 0305– 1293