INTERNATIONAL ROAD MAINTENANCE HANDBOOK PRACTICAL GUIDELINES FOR RURAL ROAD MAINTENANCEVolume III of IVPaved roadsFinanced and coordinated by TRANSPORT RESEARCH LABORATORY Revised by R C Petts of Intech Associates, UK with the financial support of ODA under assignment toTRANSPORT RESEARCH LABORATORY, UKas a development of the UN ECA handbooks prepared by joint cooperation of the governments of FRANCE, GERMANY and the UNITED KINGDOM and first published in 1982. © WORLD COPYRIGHT RESERVED 1994 Extracts from the text may be reproduced provided the source is acknowledged as follows: PIARC Road Maintenance Handbook English version published byTransport Research Laboratory, UKISBN for complete set of 4 Volumes: 0 9521860 12 ISBN for Volume 111: 0 9521860 47 FOREWORDThe road transport network of any country playsa vital role in its economy, and the physical condition of its infrastructure is critical. Without adequate and timely maintenance, highways and rural roads alike inexorably deteriorate, leading to higher vehicle operating costs, increased numbers of accidents, and reduced reliability of transport services. When repair work can no longer be delayed it will often involve extensive rehabilitation, and even reconstruction, costing many times more than simpler maintenance treatment carried out earlier. The need to protect the existing network and keep it in good condition is paramount, often taking precedence over new investment. PIARC has been in the forefront in promoting this message and in drawing attention to the dangers of neglect. The matter has become increasingly important in recent years for all the highways of the world, but especially so for those in developing countries where there is constant pressure on slender budgets and, in many, an urgent need to cater for growing traffic loads and volumes. In the late 1970's, the aid ministries of France, the Federal Republic of Germany and the United Kingdom joined forces to produce a "Road Maintenance Handbook" for maintenance foremen and workers in Africa. Published in 1982 under the auspices of the Economic Commission for Africa, the three volumes - in French and English - soon became widely known and used. By the end of the decade their use had spread far beyond Africa, and their straightforward instructions were being used for training purposes as well as for FOREWORD continuedon-the-job guidance in many countries. The need toreprint provided the opportunity to review the contents in the light of experience and make them more suitable for the wider audience now commanded. PIARC's Committee on Technology Transfer and Development, formerly the Committee on Roads in Developing Regions, undertook to help with this review, which was generously funded by the UK Overseas Development Administration. A sub-committee was established, embracing the three original donor countries, other developed and developing countries, and the World Bank. Although much of the original text has been retained, the new handbooks incorporate more information on labour and tractor-based techniques, and on the development of manpower management and the all-important question of safety at work. The range of maintenance problems addressed has been extended to strengthen their international appeal. The past ten years have seen major reforms in the general thrust of maintenance policy and in its organisation, management and execution. These changes will continue, and PIARC will play its part along with other institutions in encouraging the process and pressing for further progress. Only a full appreciation of maintenance at the highest levels of policy-making and financial planning can ensure success. But these handbooks have a humbler task-to ensure that the men and women at the operational level are suitably skilled and trained and are using the appropriate tools and techniques, and have interest and motivation in their work. FOREWORD continuedPIARC has been proud to nurture this project tothe point where the new handbooks are available, but its involvement will reach far beyond that. It will provide the necessary international framework within which the handbooks can be translated and printed in many languages. Its worldwide membership of key figures in the national provision and management of highways will assist with their dissemination, ensuring that they find their way into the most appropriate hands in both the public and private sectors. Collectively, these hands will play a fundamental part in sustaining the vital asset which our roadway networks truly represent.Victor J Mahbub,President of CONTENTSFOREWORD ................……………………………iINTRODUCTION………………………… ….viiiPart A - GENERAL REPAIRS ………………… 11. THE TASK................................................................ 32. DEFECTS…………………………………………..…………………………………2.1DEFECTS2.2LIST OF DEFECTS 7 7 73. RESOURCES…………………………………..3.1PERSONNEL3.2PLANT AND TOOLS 3.3MATERIALS 3.4SIGNS AND SAFETYEQUIPMENT4. MAINTENANCE METHODS .........................4.1PRELIMINARY TASKS4.2TEMPORARY SIGNPOSTING 4.3EXECUTION OF THE WORK 4.4COMPLETION AND REMOVAL OF TEMPORARY SIGNS4.5WORK REPORT2727 29 33 373939 47 517781 CONTENTS CONTINUEDPart B - SURFACE DRESSING (MECHANISED) .....831. THE TASK .........................................................851.1 APPLICATION85 1.2 DIFFERENT TYPES OF SURFACEDRESSING2. DEFECTS2.1 DEFECTS 2.2 LIST OF DEFECTS 3. RESOURCES 3.1 PERSONNEL 105 3.2 PLANT AND TOOLS 3.3 MATERIALS 3.4 SIGNS AND SAFETY EQUIPMENT 4. MAINTENANCE METHODS 4.1 PRELIMINARY TASKS 4.2 TEMPORARY SIGNPOSTING 4.3 EXECUTION OF THE WORK 4.4 COMPLETION AND REMOVAL OF TEMPORARY SIGNPOSTING 4.5 WORK REPORT87898989 105107111 121125125 135141157163 CONTENTS CONTINUEDPart C - RESEALING OPTIONS ..............................165 1. THE OPTIONS .......................................………...167 2. LABOUR BASED SURFACE DRESSING ..…........169 2.1RESOURCES REQUIRED171 2.2HEATING THE BINDER (for cut back bitumen)175 2.3USING BITUMEN EMULSION177 2.4SETTING OUT THE WORK179 2.5APPLYING THE BINDER181 2.6APPLYING THE CHIPPINGS183 3. FOG SPRAY......................................................185 4.SLURRYSEAL................................................... 187 CONTENTS CONTINUEDPart D - THIN OVERLAYS ......................................1911. THE TASK ……………………………………………… 1.1APPLICATION 1.2DIFFERENT TYPES OF THIN OVERLAYS 2. DEFECTS ...........................................................……193 193197199 201 201 203 205 215 217 217 229 231 253 257 3. RESOURCES ...................……………….………... 3.1 PERSONNEL 3.2 PLANT AND TOOLS 3.3 MATERIALS 3.4 SIGNS AND SAFETY EQIPMENT 4. MAINTENANCE METHODS ..................…….. 4.1PRELIMINARY TASKS 4.2TEMPORARY SIGNPOSTING 4.3EXECUTION OF THE WORK 4.4COMPLETION AND REMOVAL OF TEMPORARY SIGNS4.5WORK REPORT INTRODUCTION THE HANDBOOKThis is a guide for the maintenance foreman orsupervisor assigned to bitumen or unpaved roads in tropical and moderate climates. The objective of the HANDBOOK is to assist him in all aspects of his work whether carried out by direct labour or by contract. Its pocket format enables the volume relevant to the day's work to be easily carried and consulted on site. The HANDBOOK should be his ready reference book. The text is concise and well illustrated. A quick reference should be all that is necessary. This HANDBOOK does not include a course of study or discuss underlying causes of defects. Inspections, material sources, specifications and testing are also outside its scope. Furthermore it is sufficient here to remind the foreman that his plant and vehicles should be well maintained without telling him how to do it. Even though the HANDBOOK is intended for use by the maintenance foreman, it will also be useful reading for the engineer or senior supervisor. This will make him more conscious of his duties towards the foreman and enable him to ensure that the maximum benefit is obtained from the HANDBOOK. Each supervisor must understand his responsibility and the part he has to play. The HANDBOOK can also be used in training centres. With the assistance of country-specific supplementary information, photographic slides, models, and other supporting material, it will be a valuable tool for the trainer and can be distributed to students. Road maintenance requires a range oforganisational and technical skills and the work on roads in use by traffic makes the work potentially hazardous to both the workmen and road users. It is therefore essential that appropriate formal and on the-job training is given to each category of personnel involved in road maintenance activities to achieve efficient and safe operations. The foreman usually has an important role in the initial and ongoing training of personnel. Roads are an enormous national investment and require maintenance to keep them in a satisfactory condition and ensure safe passage at an appropriate speed and with low road user costs. Late or insufficient maintenance will increase the ultimate repair costs and raise road user costs and inconvenience, and reduce safety. Road Maintenance is therefore an essential function and should be carried out on a timely basis. There is a diversity of maintenance activities, the class and type of the road, the cross section to be maintained, the defects recognised, and the resources available. However the general methods proposed here for each activity (with some exceptions) are given under the following headings:The taskDefects Resources Maintenancemethod Where appropriate options are shown for carryingout the work by:i) Heavy Equipment,ii) Tractor based methods, or iii) Labour based methods.The decision on which method to be used should bemade by the engineer or senior supervisor based on considerations of resources available, cost, policy etc. Maintenance operations are usually grouped in each country according to planning, organisational and funding arrangements. They can normally be categorised as either ROUTINE or PERIODIC. For the purposes of this HANDBOOK the following grouping is used. ROUTINE:Operations required to be carried out once or more per year on a section of road. These operations are typically small scale or simple, but widely dispersed, and require skilled or un-skilled manpower. The need for these can, to a degree, be estimated and planned and can sometimes be carried out on a regular basis. PERIODIC:Operations that are occasionally required on a section of road after a period of a number of years. They are normally large scale and require specialist equipment and skilled resources. These operations are costly and require specific identification and planning. In this handbook PERIODIC also includescertain improvement works such as thin bituminous overlays.From time to time urgent or emergency works ofany nature may be required and these are dealt with as the need arises. The HANDBOOK consists of 4 separate volumes: VOLUME I - MAINTENANCE OF ROADSIDE AREAS AND DRAINAGE PART A - List of Terms PART B - Works Management and Safety PART C - Roadside AreasPART D - Drainage General IndexVOLUME II - MAINTENANCE OF UNPAVED ROADSPART A - Grading PART B - Labour Based Reshaping PART C - Dragging PART D - Patching PART E - Regravelling (Mechanised) PART F - Regravelling (Labour and Tractors)VOLUME III - MAINTENANCE OF PAVED ROADSPART A - General Repairs PART B - Surface Dressing(Mechanised) PART C - Resealing Options PART D - Thin Overlays111 - xi VOLUME IV - MAINTENANCE OF STRUCTURESAND TRAFFIC CONTROL DEVICES PART A - Bridges PART B - Traffic ControlDevicesVOLUME IIIEach Part A, B, C, and D describes tasksconcerning exclusively paved roads*. Roads of that category have been given a surface course, generally containing bitumen or tar, because of their importance and their higher traffic. Maintenance of the paved surface has the following objectives: • To maintain the impermeability of the road surface, preventing water penetrating the surface or edge of the road pavement and weakening the pavement layers or foundation. • To retain or renew the road surface quality and therefore good riding and safety conditions.PART A - GENERAL REPAIRSGeneral repairs are routine maintenance tasks.Sometimes they are preliminary tasks, carried out before periodic maintenance operations. NOTE - Terms with an asterisk are defined in List of Terms (See Volume 1-Part A). PART B - SURFACE DRESSING (MECHANISED)Surface dressing is a periodic maintenance task. It is used to reseal the road surface and improve the riding quality/safety. Usually it is necessary to do generalrepairs before carrying out surface dressing.PART C - RESEALING OPTIONSMechanised surface dressing is the most common typeof periodic maintenance reseal. However in certain circumstances other techniques, such as Labour Based surface dressing, Fog spray or Slurry seal are moreappropriate.PART D - THIN OVERLAYSA thin overlay is a periodic maintenance task. It is usedto reseal the road surface, cover minor depressions or strengthen the road pavement. As with surface dressings, it is frequently necessary to do general repairs in preparation. An existing road surface that is cracked should not be overlaid without an investigationof the cause by the engineer.NOTE: In many countries women carry out roadmaintenance tasks and supervisory duties. The use of male descriptions and diagrams in this handbook is for convenience only. The guidelines are applicable whether the work is carried out or supervised by menor women.III - xm Part AGENERAL REPAIRS NOTE: SHOWN FOR DRIVING ON THE RIGHT PART A - GENERAL REPAIRS1. THE TASKGENERAL REPAIRS are normally a ROUTINEMAINTENANCE activity. However they are also carried out in advance of some PERIODIC MAINTENANCE operations.  The term General Repairs covers all types of work on the road pavement*:  of a localised nature and of limited size. The OBJECT is to: improve the surface condition of the road improve the pavement* structure  prevent water penetrating the pavement structure General Repairs must be carried out in goodtime in order to prevent further deterioration resulting in danger to traffic and leading to disintegration of the pavement. General Repairs employ simple methods butcover a large range of small work operations.  Due to the materials, skill and safetyrequirements, this task is usually carried out by a mobile gang See List of Terms, Volume I PART A - GENERAL REPAIRS A particular General Repair technique isinvolved for each type of defect. This Part of the Handbook deals with the following techniques*:SANDINGLOCAL SEALING CRACK SEALING FILLING IN DEPRESSIONSSURFACE PATCHINGIn the case of surface repairs, use is made ofbituminous binders, sands and aggregates.In the case of repairs to the pavement structure,use is made of natural or crushed materials and sometimes of cold bituminous mixtures. Often when work is carried out on pavementGeneral Repairs, it is also necessary to repair defects on the shoulders* and side ditches when the pavement defect is due to them. This will help to prevent the problem recurring. e.g., - construction or cleaning out of ditches,- construction or cleaning of drainage outlets, - patching and reshaping of shoulders.* See List of Terms, Volume 1. PART A - GENERAL REPAIRS2. DEFECTS2.1 DEFECTSDefects can occur in:  The road surface (a)  wear of the surface layer of the road,  cracking of the surface layer,  fatting-up of binder to the road surface.  The pavement structure (b)  deformation, potholes.2.2 LIST OF DEFECTSInformation follows on the different types of defect with respect to:  Location: parts of the pavement where the defectusually appears, Main Causes of the defect, Development: consequences if maintenance is not rapidly carried out,  Remedies: usual repair treatments. PART A - GENERAL REPAIRSDEFECT: BLEEDING*LocationMay involve a part or the whole of the roadsurface.Main causes- too much binder, -unsuitable binder.Development, if neglected- the road surface becomes slippery when wet, -separation and break-away of surface layer under the action of traffic.Remedies- sanding (Page III - 51), -surface dressing (Page III – 83).See List of Terms, Volume I. PART A - GENERAL REPAIRSDEFECT: CRACKS(in the surface and in the pavement structure)Locationa.longitudinal: parallel to the centre line (often along the wheel tracks or along the edges of the surfacing). b.transverse: perpendicular to the road direction (across the whole or part of the cross-section). c.mesh cracking: intersecting cracks dividing the pavement surface into isolated elements of different sizes down to the small elements involved in crazing. Main Causes - poor quality materials, - poor workmanship, -insufficient pavement thickness for the traffic being carried, -shrinkage (see Note), -pavement age. NOTE:Shrinkage: cement treatment of road base results in areduction in volume after the cement has set and dried out. PART A - GENERAL REPAIRSDEFECT: CRACKS (Continued)Development, if neglected-a general or local destruction of the pavement. Remedies -surface cracking: local sealing (Page III - 53) or filling-in of the cracks (Page III - 57). -cracks in the pavement structure: local sealing (Page III - 53) or filling-in of the cracks (Page III - 57), and patching in cases of severe cracking (Page III - 71). NOTE:In the case of extensive cracking of the surface or the pavement structure (without rutting or deformation), surfacedressing will be necessary (see Part 8 or C). PART A - GENERAL REPAIRSDEFECT: RUTS AND DEPRESSIONSLocation-in the wheel tracks of vehicles (ruts), -local areas (depressions*). Main Causes -insufficient foundation or pavement strength for the traffic being carried, -inadequate stability of the bituminous* surfacing materials. Development, if neglected -if water is able to penetrate into the body of the pavement, then there will be a rapid increase in the degree of rutting often leading to cracking and breakup of the pavement. Remedies -slight rutting (less than 5 cm): filling in of the ruts and depressions (Page III - 63), -deep rutting: local restoration of the pavement structure (Page III - 71). *See List of Terms, Volume 1. P ART A - GENERAL REPAIRSDEFECT: EDGE SUBSIDENCE AND RUTTINGLocationUsually along the edges of the pavement where it borders unsealed shoulders. Main Causes - inadequate or badly maintained shoulder - penetration of water into the pavement structure or foundation and resulting loss of bearing strength, - poor drainage, - narrow carriageway. Development, if neglected -rapid during the rainy season leading to the disintegration of the edges of the pavement. Remedies -slight subsidence (less than 5 cm): filling in of ruts and depressions (Page III - 63) and restoration of shoulder (see Volume I), -deep subsidence: local restoration of the pavement structure (Page III - 71) and restoration of the shoulder (see Volume I), Also consider improvements to the drainage (see Volume I), or sealing of the shoulder (Part B or C) to help prevent the problem recurring. PART A - GENERAL REPAIRSDEFECT: EDGE DAMAGE(degradation of pavement structure)LocationAlong the edges of thepavement'`.Main Causes- wear of the shoulder* (formation of step), - action of water, - insufficient compaction of the edges of bituminous pavements,- road too narrow.Development, if neglected- rapid during the rainyseason.Remedies- local restoration of the pavement structure (Page III -71).*See List of Terms, Volume I. PART A - GENERAL REPAIRSDEFECT: LOCAL AGGREGATE LOSSLocationSmall areas or strips of the road surface. Main Causes - Loss of surface aggregate due to: insufficient binder due to faulty spray jet, - aggregate dirty when laid, - insufficient penetration of aggregate, - poor premix quality or workmanship. Development, if neglected - minor stripping/fretting/streaking'*. Remedies - surfacing patching (Page III - 67). *See List of Terms, Volume I. NOTE: For large areas of aggregate loss, surface dressing should be considered as a remedy (Part B or C). III - 23PART A - GENERAL REPAIRSDEFECT: POTHOLES(degradation of the pavement structure)LocationNo particular location but often in areas showing cracks, deformation or aggregate loss.* Main Causes -poor quality of material used for the construction of the pavement, - infiltration of water, - break away of material under the action of traffic, -final stage in the development of crazing* or of a depression*. Development, if neglected -progressive enlargement of the hole and formation of additional potholes. Remedies -local restoration of the pavement structure (Page III -71).*See List of Terms, Volume I. PART A - GENERAL REPAIRSDEFECT: SHOVING (defects in the surface or pavement structure) Location Usually on either side of the wheel tracks. The irregularities are usually associated with deformation and subsidence. Main Causes -ingress of water: reduced bearing capacity of the pavement, - materials: of poor quality, - workmanship: insufficient compaction, -traffic: passage of vehicles which are too heavy for the pavement structure. Development, if neglected - forcing up of weak materials as deformation occurs, -progressive disintegration of the pavement. Remedies -small irregularities: filling in of irregularities (Page III - 63), -large irregularities together with cracks: local restoration of the pavement structure (Page III - 71).III - 25 PART A - GENERAL REPAIRS3. RESOURCES3.1 PERSONNEL Work Force 1 foreman, 1 spray lance/bitumen operator,  2 to 4 workmen, 2 traffic controllers. Plant Operators and Drivers 1 patching vehicle* driver, 1 tipper/flat bed truck driver, 1 vibrating roller operator.OR 1 tractor driver, 1 vibrating plate operator. *If this vehicle is available.III - 27 PART A - GENERAL REPAIRS3.2 PLANT AND TOOLS Patching Vehicle*Specially equipped vehicle or towed equipmentfitted with a heated tank for the binder and a double hopper for the aggregates.ORIf, not available, a suitable means of heating(unless bitumen emulsion is used) and applying the bitumen are required. e.g. towed bitumenheater/distributor. Tipper/Flat Bed Truck, or Tractor and TrailerFor transporting the aggregates, small items of equipment and the personnel. If such a vehicle is not available a truck or tractor & trailer is used totransport: the personnel,  the equipment,  the aggregates,  binder in drums,  premixed materials (if used). PART A - GENERAL REPAIRS A small vibrating roller (or, if not available, avibrating plate compactor or hand rammers) for use in compacting the aggregates and other materials. The vibrating roller can be transported by mounting it on a special trailer which is towed by the truck. Otherwise ramps or a hoist are required to help load onto truck or trailer. Small items of equipment:-2 wheelbarrows, -4 shovels, -4 pickaxes, -2 hand rammers, -4 brooms, -2 watering cans, -2 squeegees, - bitumen thermometer. If bitumen emulsion is used 1 cold emulsion single drum sprayer.Tools and supplies-1 drum of diesel oil for use in cleaning the spray lance*, and other tools, -1 spare jet for the spray lance, -1 box of tools for use in dismantling the spray lance, -rags, -number of paint brushes, -1 metal bucket, -1 two-metre straight edge, -chalk for marking.*See List of Terms, Volume 1. III - 33PART A - GENERAL REPAIRS3.3 MATERIALSThe materials used consist of aggregates*, andbituminous binders* that are either applied separately or in the form of a bituminous mixture. Aggregates** The aggregates may be:  sand mixtures* ................................d/D (a) stone chippings* .............................d/D (b) natural gravel or crushed rock ........d/D (c)The materials should meet the gradingrequirements set by the engineer. The maximum size of aggregate varies according tothe type of work involved, normally: sanding ...............................Dmax = 5 mm surfacing .............................Dmax=10 mm base courses . …… Dmax =40 mm (Dmax = nominal maximum diameter)In addition to the grading it is also necessary tocheck the hardness and the cleanliness of these aggregates. These properties should be testedregularly according to the specifications.*See List of Terms, Volume 1. **For Aggregate abbreviations see Page III - III. III - 35PART A - GENERAL REPAIRS Bituminous binder*This can consist of:  a cold bitumen emulsion (a), a hot cut back bitumen (b).The bitumen is either applied to the road surfaceas a film or used in bituminous mixtures. Bitumen filmThe bituminous binder is applied with a spray bar/lance*, or by hand from a measuring container, to cover the surface and ensure that it will be impervious to water. The bitumen film is covered with stone chippings or aggregates to provide protection from traffic. Bituminous mixtures (c)The bituminous binder is used to bond the other materials together. Bitumen mixtures can consistof: bitumen emulsion slurries - applied immediatelyafter manufacture,  cold bitumen emulsion mixtures - manufactured in advance of their application,  hot fluxed or cut back bitumen mixtures (hot mix) applied immediately after manufacture.*See List of Terms, Volume I. PART A - GENERAL REPAIRS3.4 SIGNS AND SAFETY EQUIPMENT Advance Warning Signs The following signs are to be placed on the shoulder for both directions of traffic:  2 "Men Working" signs, 2 "End of Restriction" signs. Site Protection Equipment: 4-10 traffic cones, 2 reversible Safety EquipmentUse should be made of the following equipment for personnel and the different vehicles as far as possible:  yellow/orange shoulder belts for the foreman, the spray lance operator and the other workmen,  red and white striped marker boards attached to the patching vehicle, the truck or tractor and trailer. A fire extinguisher should be provided for each vehicle working with or near heated bitumen. TYPICAL WORKSHEETGENERAL REPAIRSWorksheet No: . . . . . . . . . . . . . . . . . . Date: . . . . . . . . . . . . . . . . . . . . . District: ................................................. Zone:......................................................Gang: Road No:. . . . . . . . . . . .from km ......................to km............ from km ......................to km............ from km ………………to km ………. TYPE OF REPAIR: Sanding Local sealing Crack sealingFilling in depressionsMATERIALS: Type of binder: . . . . . Aggregates: . . . . . . . . Bituminous mixtures: QUANTITIES REQUIRED: Binder: . . . . . . . . . . . …………………………………………………………kg Aggregates: . . . . . . . . ………………………………………………………..m3 Bituminous mixtures………………………………………………………… .m3STOCK POSITION & COMMENTS:……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………………Surface patching Base patching Resurfacing of shoulders III - 39PART A - GENERAL REPAIRS4. MAINTENANCE METHODS4.1 PRELIMINARY TASKSSuccessful results for General Repairs depend ongood preparation and organisation of the work. There are three preparation activities:1 Refer to the WorkSheetsThese sheets give the dates when work onthe road section concerned is to be carried out, the activities required, as well as information on the materials that are to be used. III - 41PART A - GENERAL REPAIRS2 Examine the section of road to be repaired The section of road to be repaired must be examined along its whole length in order to determine:  the types of defect to be repaired (Pages III - 7 to III - 25), the extent of the defects, and to  check the resources required. III - 43PART A - GENERAL REPAIRS3 Resource AvailabilityBefore the work starts it is necessary to ensure:  that all necessary personnel are available, that all items of equipment to be used are availableand in good condition,  that all small items of equipment, hand tools andthe necessary traffic signs are available, PART A - GENERAL REPAIRS that the required type and quantity ofbinder, as specified on the work sheet, isavailable, that the aggregate is available at thestorage locations specified on the worksheet. PART A - GENERAL REPAIRS4.2 TEMPORARY SIGNPOSTINGTraffic signs conforming to the regulations must becorrectly placed before starting any work. This is to ensure the safety:  of the road users,  of the personnel working on the site,  of the vehicles and equipment to be used on the site. PART A - GENERAL REPAIRSThe signs are: located on the shoulder on the side of theapproaching traffic, 100 m ahead of each end of the roadworks: 1 "Men Working" sign, located along the length of theroadworks: to 10 traffic cones, as required to clearlyseparate the traffic from the roadworks. located on the shoulder on the side of thedeparting traffic, at each end of the site:  1 "End of Restriction" sign. NOTE: In busy traffic 2 men must be assigned to direct the traffic in alternate directions past the roadworks.III - 49 III - 51PART A - GENERAL REPAIRS4.3 EXECUTION OF THE WORKSANDINGSanding is the treatment to be used where theroad surface is bleeding*, coarse sand up to 5 mm should be used where possible. Two activities, which may need to be repeated, are involved in the treatment: 1The sand is scattered by shovel over the affected surfaces from a truck or trailer (a). 2The sand is then spread out with a broom so that the surface is evenly covered (b).* See List of Terms, Volume 1. PART A - GENERAL REPAIRSLOCAL SEALINGThis treatment is used to repair cracks (Page III -11). It is also employed as the final treatment in the case of any local repair to the road (Page III - 71).The treatment is applied in four stages:1 Sweep the area (a)This is carried out by hand. The road surfacemust be clean and dry following this operation.2 Mark out the area to be sealed (b)The surfacing that is to be covered is outlined in chalk. PART A - GENERAL REPAIRS3 Distribution of the binder (c)The binder is distributed over the surface using aspray lance'` or a watering can at the following rates:1.5 kg/M2 for bitumen emulsion, 1 kg/m 2 for cut back bitumen. 1 kg/m 2 for cut back bitumen.It is important not to overheat the cut backbitumen or cationic emulsion as this will affect its durability. A thermometer should be used to check the temperature during heating (see Page III - 143). Anionic emulsion does not normally require heating. Smoking should not be allowed when handling cut back bitumen.4 Distribution of the aggregate (d)The aggregate is scattered by shovel from the truck ortrailer. The material used is:  coarse sand up to 5 mm, when dealing with cracks,  chippings (such as 6-10 mm size) for local surfacing repairs. The whole of the surface must be covered. *See List of Terms, Volume 1. NOTE: When chippings are applied, they must be compacted with thesmall roller. PART A - GENERAL REPAIRSCRACK SEALINGThis is an alternative treatment used to repair cracks(Page III - 11). Treatment of closely spaced cracks The cracks are filled in with a bituminous slurry in four steps: 1 Sweep the area (a) This is carried out by hand. The road surface must be clean and dry following this operation.2 Mark out the area to be repaired (b)The area to be repaired is outlined with chalk. PART A - GENERAL REPAIRS3 Production of the slurry (c)The slurry is produced by mixing bitumenemulsion with coarse sand, up to 5 mm, in a wheel barrow in the following proportions:  sand 20 litres emulsion 6 litresThe emulsion does not normally require heating.However the emulsion drums will require rolling to thoroughly mix the contents before use.4 Spreading the slurry (d)This is carried out with a squeegee*. Thematerial must be spread out in a thin layer, approximately 5 mm thick, over the whole of the marked out area. The slurry must be allowed to dry completely before allowing traffic to passover the repair.*See List of Terms, Volume I PART A - GENERAL REPAIRSCRACK SEALING (Continued)Treatment of Isolated CracksIn these cases the cracks are filled in with a hot cutback bitumen.1 Sweeping the area (a)The crack to be filled must be clean following thisoperation.2 Heating the binderDo not overheat the cut back bitumen as this willaffect its durability. Use a bitumen thermometer to check the temperature during heating (see Page III -143).3 Distribution of the binder(b)This is carried out using a spray lance orwatering can to follow the line of the crack. The nozzle of the spray lance or the spout of the watering can must be held close to the road surface. The width of spread should be kept as small as possible.4 Distribution of the sand(c)Coarse sand is scattered over the strip of binderusing a shovel. PART A - GENERAL REPAIRSFILLING IN DEPRESSIONSThis treatment is applied to deal with subsidence(Page III - 15) and surface irregularities due to shoving (Page III - 25). The depressions are filled with a cold mix asphalt* prepared in advance and stored at the depot. The repair is carried out in six steps:1 Sweep the area (a)The depressions must be swept out by hand. Thesurface of the depression must be clean and dry.2 Mark out the area to be repaired (b)The surface area of the depression that is to be filled in must be outlined with chalk.Remove any high spots with a pick axe.3 Obtain the cold mix(c)* See List of Terms, Volume I. PART A - GENERAL REPAIRS4 Application of a tack coat (d)Hot cut back bitumen is applied with a spraylance or watering can at a rate of about 0.5 kg/m2. Do not overheat the cut back bitumen as this will affect its durability. Use a bitumen thermometer to check the temperature duringheating.5 Fill in the depression (e)The cold mix is placed within the marked outlineusing a rake and leaving an excess thickness of about one third of the depth of the depression in order to allow for compaction.6 Compaction of the material (f)The material is compacted thoroughly using thesmall vibrating roller, plate or a rammer, until the level is 3 mm proud of the surrounding surface.7 ResealingThe repair must be sealed to prevent penetrationof water (Page III - 53). PART A - GENERAL REPAIRSSURFACING PATCHINGThis treatment is used to repair local aggregate loss(Page III - 21) and is carried out in the followingsteps:1 Sweep the areaThe area must be swept out by hand. The surfacemust be clean and dry.2 Mark out the area to be repairedThe surfacing that is to be repaired is outlined inchalk.OPTION 1: SEALUse cold emulsion or hot cut back bitumen to sealthe area to be repaired and provide a tack coat atthe following rates: 1.5 kg/m2 for bitumen emulsion kg/m2 for cut back bitumen.Apply the chippings (such as 6-10 mm size) andensure a complete coverage. Lightly roll the chippings into the bitumen using a roller or vehicle tyres. PART A - GENERAL REPAIRSOPTION 2: PREMIXA hot cut back bitumen is applied to the area of therepair with a spray lance or watering can, at a rate of about 0.5 kg/m2 to form a tack coat. Spread fine cold mix (made from material up to 5 mm size) evenly over the area and compact it level with the surrounding surface using the small vibrating roller or plate, or a rammer. PART A - GENERAL REPAIRSBASE PATCHINGThis is the treatment that is used to repair: mesh cracking (Page III - 11),  ruts and depressions (Page III - 15),  edge subsidence and rutting (Page III -17),  edge surface failure (Page III - 19),  potholes (Page III - 23),  shoving (Page III - 25).Four steps are involved:1Marking out the area to be repairedThe area to be treated is marked out with chalk by drawing a rectangle around the defects. PART A - GENERAL REPAIRS2 Excavation of the area to be repairedIt is necessaryto: remove all material from within themarked out area of the road surface, increase the depth of the hole until firm, drymaterial is found and then trim the walls of the hole so that they are vertical. If water or excessive moisture is present, then arrangements must be made to drain it away from the pavement foundation.  trim the bottom of the hole such that it isflat, horizontal and free from loose material then compact it.III - 73 PART A - GENERAL REPAIRS3Backfilling the holeThe hole is filled with a selected well gradedmaterial brought to the site in a truck or trailer. This material can consist of:  a material of the same quality as that of the base layer that is to be repaired, or a cold mix asphalt*.The material is placed in the hole and compacted inone or more layers of regular thickness depending on the depth involved. The last layer, prior to compaction, must have an excess thickness of about 1/5 the depth of the final layer, in order toallow for settlement on compaction.Compaction is continued depending on the size ofthe excavation, using the vibrating roller, plate compactor or with a yammer, until the surface islevel.4ResealingThe repair must be sealed to prevent penetration ofwater (Page III - 53).*See List of Terms, Volume I. PART A - GENERAL REPAIRS4.4 COMPLETION AND REMOVAL OF TEMPORARYSIGNS On completing the repairs and before removing the traffic signs which protect the site, the following activities must be carried out: remove all excavated material from the road, sweep all aggregate from the edges of therepairs, sand all areas where too much binder hasbeen applied. In the days following completion of the work, all areas where the binder has migrated to the road surface must also be sanded again. NOTE: SHOWN FOR DRIVING ON THE RIGHT PART A - GENERAL REPAIRS On completion of the repairs and finishing thework, park the vehicles on the shoulder. The two men who have been responsible for directing the traffic will remove the traffic signs and load them on the truck in the followingorder: the traffic cones(a), the two "End of Restriction"  signs, the two "Men Working" signs (b). TYPICAL WORK REPORTGENERALREPAIRSWork Report No: . . . . . . . . . . . . . . . . . Date: . . . . . . . . . . . . . . . . . . District:……………………………………………………………………. Zone: ......................……………….. Road No:. . . . . . . . . .Gang: ..……from km ...................to km………………… from km ...................to km……………….. from km ...................to km………………..TYPE OF REPAIR:Sanding Surface patching Local sealing Base patching Crack sealingResurfacing of shoulders Filling in depressions MATERIALS USED: Type of binder: . . . . …………………………………………………… Aggregates: . . . . . . . ………………………………………………….Bituminous mixtures: . …………………………………………………QUANTITIES USED: Binder: ..................................................................................................kg Aggregates: ........................................................................................m3 Bituminous mixtures: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . m 3COMMENTS:……………………………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………….Foreman .....................................................Date:………………………. PART A - GENERAL REPAIRS4.5 WORK REPORTThis report must be filled in each day detailing:  the work carried out,  the resources used. Part BSURFACE DRESSING(mechanised) PART B - SURFACE DRESSING (mechanised)1. THE TASKSURFACE DRESSING is normally a PERIODICMAINTENANCE activity.1.1 APPLICATION A surface dressing can be used for dealing with alarge road surface area where:  the surface is extensively worn, the surface has become permeable or cracked allowing water to penetrate the base and cause deterioration,  there is inadequate surface texture so that skid resistance is reduced, It will usually be necessary to carry out somepatching work before proceeding with this operation, particularly where there is base damage, subsidence, potholes, etc.  The surface dressing is generally applied over the complete width of the pavement (although in some cases, over only a half width) and over lengths of road ranging from a few hundred metres to several kilometres.  With good planning and organisation, this work can achieve high outputs.  Surface dressing must be applied only in dry weather.  Surface dressing will not correct depressions, and deformation of the road pavement or severe cracking. PART B - SURFACE DRESSING (mechanised)1.2 DIFFERENT TYPES OF SURFACE DRESSINGA distinction is made between:  Single surface dressing (a):  1 layer of bituminous binder, 1 layer of chippings. Double dressing (b): 2 layers of bituminous binder, each covered witha layer of chippings. Graded seal (c): 1 layer of bituminous binder, followed by either: 2 layers of chippings of different compatible sizes e.g. 10/14 and 4/6, the second layer serving to fill the gaps between the larger first stones and completely cover the road surface, or 1 layer of graded aggregate or gravel with stonegraded over a wide size range (e.g. 3 to 17 mm). Sandwich seal 1 layer of chippings (e.g. 10/14), 1 layer of bituminous binder, 2nd layer of chippings (e.g. 4/6).This seal is suitable for existing surfaces withextensive bleeding. III - 87 PART B - SURFACE DRESSING (mechanised)2. DEFECTS2.1 DEFECTSDefects treated by surface dressing are usuallythose involving large areas of the road surface:  wear of the surface layer, permeable surface, migration of binder to the surface.The use of a surface dressing can sometimesprevent any increase in the deformation of the pavement structure (preventive treatment).2.2 LIST OF DEFECTSInformation follows on the different types of defectwith respect to:  Location: parts of the pavement where the defect usually appears, Main causes of the defect, Development: consequences if maintenance isnot rapidly carried out,  Remedies: usual repair treatment. PART B - SURFACE DRESSING (mechanisedDEFECT: BLEEDING*LocationMay involve part or the whole of the roadMain causes too much binder, unsuitable binder.Development, if neglected separation and breakaway of surface layer under the action of traffic,Remedies sanding (see Page III - 51),  surface dressing.*See List of Terms, Volume I. PART B - SURFACE DRESSING (mechanised)DEFECT: CRACKS(in the surface and the body of the pavement)Locationa) longitudinal: parallel to the centre line (often along the wheel tracks or along the edges of the road). b) transverse: perpendicular to the road direction (across the whole or part of the cross-section). c) mesh cracks: intersecting cracks dividing the pavement surface into isolated elements of different sizes down to the small elements involved in crazing. Main causes  poor quality materials,  poor workmanship,  insufficient pavement thickness for the traffic being carried,  shrinkage (see Note),  pavement age. NOTE:Shrinkage: cement treatment of road base results in a reduction in volume after the cement has set. PART B - SURFACE DRESSING (mechanise)Development, if neglected a general or local disintegration of the pavement. Remedies -surface cracking: application of a surface dressing, -severe cracks in the pavement structure: patching (Page III - 71) followed by the application of thesurface dressing. PART B - SURFACE DRESSING (mechanised)DEFECT: GLAZING*LocationThe pavement surface ingeneral.Main causes wear but no removal of the surface chippings (a),  embedment of the chippings into the base (b). Development, if neglected -continued wear of the chippings resulting in the pavement surface becoming more and more slippery, particularly when wet. Remedies  application of a surface dressing,  application of a thin bituminous overlay (see Part D).*See List of Terms, Volume 1. PART B - SURFACE DRESSING (mechanised)DEFECT: LOSS OF SURFACE AGGREGATE(Stripping/fretting)*Location On surface dressing or premix surfacing. Usually in wheel tracks. Main causes Breakaway of surface aggregate or seal due to:  poor adhesion of the surface dressing to the base,  aggregate dirty when laid,  insufficient penetration of aggregate,  poor premix quality or workmanship,  insufficient or erratic distribution of binder. Development, if neglected - progressive break-away of chippings resulting in the surfacing becoming more slippery, more permeable, or worn out by traffic. Remedies  application of a surface dressing, or, - application of a thin bituminous overlay (see Part D).* See List of Terms, Volume I. PART B - SURFACE DRESSING (mechanised)DEFECT: STREAKING*LocationParallel to the centre line and extending over appreciable lengths. Main cause  faulty operation of the spraying equipment applying the surface dressing, giving rise to streaks of insufficient binder. Development, if neglected -the surface will become more permeable and potholes or deformation will probably occur. Remedies  application of a surface dressing,  application of a thin bituminous overlay (see Part D).*See List of Terms, Volume I. PART B - SURFACE DRESSING (mechanised)DEFECT: DEFORMATIONLocationVarious forms of local settlement of the pavement, usually along the wheel tracks, or along the edges of the road. Main Causes  insufficient strength of the pavement structure or foundation,  inadequate stability of the surface layer (bituminous mixture). Development, if neglected  rapid increase in the settlement during the rainy season and a break up of the pavement if water penetrates thebase.RemediesSlight subsidence:  application of a surface dressing as apreventive measure.Appreciable subsidence: patching (Page III - 71) followed by theapplication of a surface dressing or a thinoverlay (see Part D).NOTE:A slurry seal (Part C) can be applied in place of a surfacedressing when the subsidence is not excessive. PART B - SURFACE DRESSING (mechanised)3. RESOURCES3.1 PERSONNEL Working Force  1 foreman, 1 overseer,  1 spray bar operator,  1 attendant for aggregate trucks,  2 - 4 chip spreading labourers,  2 traffic controllers. Plant Operators and Drivers 1 mechanical broom operator, 1 bitumen distributor driver,  or 4 aggregate truck drivers,  2 roller operators,  1 loader operator (for the loading of chippings),  1 truck driver,  1 light vehicle driver. III - 107PART B - SURFACE DRESSING (mechanised)3.2 PLANT AND TOOLS 1 mechanical broom, 1 bitumen distributor of 5,000 to 8,000 litrescapacity, with working thermometer, 3 or 4 aggregate trucks each of 5 to 6 m 3capacity and fitted with tailgate gritters*,  2 rubber tyred rollers with tyres inflated to apressure of 6 kg/cm 2 , 1 wheeledloader, 1 lightvehicle, 1 tippertruckNOTE: If a self propelled chipping spreader is available, the aggregate trucks will not require tailgate gritters.See List of Terms, Volume PART B - SURFACE DRESSING (mechanised) Test Equipment calibration tray and test equipment formeasuring bitumen rate of spread. Small Items of Equipment 2-4 shovels, brooms,  2 rakes,  2 pickaxes,  2 wheelbarrows. Tools and Supplies rolls of strong paper (at least 50 cm wide), 1 drum of diesel oil to clean the spray bar and tools,  a number of spare spray bar jets,  1 box of tools for use in dismantling the spray bar jets and adjusting the chipping equipment,  oil drums cut along their axis to collect bitumen during testing of spray bar,  box of rags,  paint brushes,  metal buckets,  chalk or paint for marking,  stringlines,  half drums for testing spray bar jets. PART B - SURFACE DRESSING (mechanised)3.3 MATERIALSThe materials required for surface dressingusually consist of:  one or several types of aggregate" (chippings),  a bituminous binder*. AggregatesAggregates are obtained from approvedsources and the material has usually been crushed. It is normally delivered to the work site as a uniformly graded material where: d: is the size of the smallest particles in millimetres,D: is the size of the largest particles, again inThe most commonly employed d/D gradings areas follows:4/6 - 6/10 - 10/14Sometimes a "graded seal" is used by makingtwo applications of aggregate of two different sizes, or one application of a continuously graded aggregate.*See List of Terms, Volume 1. PART B - SURFACE DRESSING (mechanised) lAggregates to be used for surface dressing must conform to thespecifications and:  have a given grading (as specified on the work sheet) (a),  be of a suitable shape, preferably cubical (b),  be strong enough so that they will not crush under traffic, (c),  be sufficiently clean. Dirty or dusty aggregate will not adhere to the bitumen, (d). If aggregates are dusty they should be: washed, or lightly sprayed with diesel, creosote orkerosene before use (pretreating). This will promote bonding with the bitumen. The pretreating can be achieved by mixing at the stockpile, by spraying on a belt conveyor or byusing a concrete mixer. III - 115PART B - SURFACE DRESSING (mechanised)Use is made of:  a single uniformly graded aggregate in thecase of a single surface dressing (e), or  two uniformly graded aggregates in the caseof a double surface dressing, or  a single surface dressing with two layers of chippings (f), or  a single continuously graded aggregate in thecase of a "graded seal" (g),NOTE:The grading classification of the aggregate and the shape, strength and cleanliness of the aggregate particles will be the subjects of laboratory tests poor to making use of the material. PART B - SURFACE DRESSING (mechanised) Bituminous Binders* Different types of bituminous binder are available: penetration grade bitumens (a),  cut back bitumens (b),  bitumen emulsions (c).These three different types of binder are classified in thelaboratory in terms of:  the penetration in the case of the penetration grade bitumens (d),  the viscosity in the case of the cut back bitumens (e),  the bitumen content and breaking speed in the case of the emulsions (f). These classifications are determined by carrying out tests illustrated opposite. * See List of Terms, VolumeNOTE. The type of border to be used is determined as a function the road temperature  the climate (dry or wet weather)  the heating facilities available,  the type of aggregate to be used PART B - SURFACE DRESSING (mechanised)Successful surface dressing depends on thedegree to which the binder adheres to the aggregate (good bonding characteristics). The binder and aggregates must be selected according to the results of a laboratory study aimed at establishing the suitability of the aggregates and the binder for surface dressing. In some cases an additive may be mixed with thebinder to improve bonding.If on site it is found that the binder does not adherewell to the aggregate (poor bonding characteristics),then it will be necessary to: stopwork, inform the responsible person collect samples of the binder and aggregate foruse in carrying out further laboratory tests. PART B - SURFACE DRESSING (mechanise3.4 SIGNS AND SAFETY EQUIPMENT Advance Warning Signs (a) The following signs are to be placed on the shoulder for both directions of traffic:  2 "Men Working" signs, 2 "Road Narrows" signs, (one each hand),  2 "Loose Chippings" signs,  2 "No Overtaking" signs, 2 "Speed Limit" signs (50 km/hr). Site Protection Equipment(b)The following signs are to be erected on theroad to define the boundary of the roadworks:  2 "Lane Closed" barriers with "End of Roadworks" written on the reverse side,  100 traffic cones per kilometre length ofroadworks, 2 reversible "Stop/Go"signs.NOTE: When the surface dressing is to be applied m one pass over the full width of the road, it will be necessary to desert the traffic and to make use of the warning and diversion signs shown opposite (c). PART B - SURFACE DRESSING(mechanised End of Restriction Signs (d)The following signs are to be placed on theshoulder for each direction of traffic: 2 "End of Restriction" signs. Safety Equipment (e)Use is to be made of the following equipment forpersonnel and vehicles:  yellow shoulder belts for each of the traffic control operators located at the beginning and end of the roadworks, and all workmen,  signs marked with alternate red and white diagonal strips for mounting on the vehicles,  if possible, a triangular sign fitted with three flashing lights for mounting on the roof of the light vehicle. A fire extinguisher should be provided for each vehicle working with or near heated bitumen. TYPICAL WORKSHEETSURFACE DRESSINGWorksheet No:…………….. District: . . . . . . . . . Zone:. Road No:.............. Section: from km: . . . . . . . . Type ofDate:.................................................................Gang:from: ...........................to:to km:. . . . . . . . . . . in . . . . . . m widthRates of spread:1 st layer . . . . . . kg/m2................................................................................2nd layer...............kg/m2Type of aggregate: 1st layer . . . . . . . . . . . . . . . 2nd layer . . . . . . . . . . .Rates of spread (I/m2): 1st layer . . . . . . . . . . .Binder . . . . . . . . . . . tQuantities required: Aggregate .......................m3 Of Aggregate .....................................................m3 of Stocks: Binder: .....................t Aggregate:................m3.................................m3...................................... 2nd layer III - 125PART B - SURFACE DRESSING (mechanised)4. MAINTENANCE METHODS4.1 PRELIMINARY TASKSTo achieve successful results it is essential toproperly plan, prepare and organise surfaceThere are four preparationactivities:1 Refer to the Work SheetThis contains all the information needed to plan andorganise the work. PART B - SURFACE DRESSING (mechanised)2EquipmentCheckOne week before work is to start, a check should bemade to ensure: that all items of equipment to be used are in goodcondition, that arrangements have been made for providingthe vehicles with fuel,  that arrangements have been made for carrying out maintenance work on the equipment,  that all personnel are available (Page III - 105), III - 129PART B - SURFACE DRESSING (mechanised) that all hand tools and traffic signs areavailable, that arrangements have been made for the supplyof the binder and aggregate, and that the quality and quantity of these materials and the locations where they are to be stored are as specified on the work sheet,  that all bitumen heating equipment andpumps are available. III - 131PART B - SURFACE DRESSING (mechanised)3 Check that the Preparatory Work has been carriedout The success of the surface dressing depends on the proper preparation of the existing surface. This preparation is carried out by the General Repairs gang. A week before work is to start it is necessary to ensure:  that all potholes have been repaired (see Part A),  that the edges of the road have been repaired (see Part A),  that the existing surface is clean and free of dirt, or other debris that would affect the bond of the new surface dressing (clean if necessary). PART B - SURFACE DRESSING (mechanised)4Organise the WorkThe day before work starts, the foreman  inspect the condition of the existing surface for the last time to ensure that it is clean, that it has been properly repaired and that the edges of the road where they join onto the shoulder are properly defined,  assess likelihood of good  send the mechanical broom and the rollers to the site and locate them off the road, if possible, to protect both the road users and the equipment. PART B - SURFACE DRESSING (mechanised)4.2 TEMPORARY SIGNPOSTINGTraffic signs conforming to the regulations must be correctly placed before starting any work. This isto ensure the safety: of the road  of the personnel working on the site,  of the vehicles and equipment to be used on the site. The traffic signs must be  ahead of the worksite (in both traffic directions) to give advance warning of danger,  along the length of the roadworks to protect the site from traffic when it is not possible to build a diversion,  at the end of the roadworks as an indication that there is no further restriction. III - 137PART B - SURFACE DRESSING (mechanisedTraffic signs will consist of: Ahead of the Roadworks (for both directions oftraffic), on the shoulder on the side of the approaching traffic:  "Men Working", "Loose Chippings",  "Road Narrows",  "No Overtaking",  "Speed Limit" (50 km/hr). On the half-width of road where work istaking place, at each end of the works:  1 traffic barrier, 1 man controlling successive flows of traffic in alternate directions. Along the length of the roadworks: traffic cones.On long works sections intermediate trafficcontrollers may be required to transfer "Stop/Go" instructions. Alternatively portable traffic lights or hand radio sets should be used. III - 139PART B - SURFACE DRESSING (mechanised) At the end of the roadworks (for both directions oftraffic).  on the shoulder on the side of the departing traffican: "End of Speed Restriction" sign should be placed 50 metres beyond the traffic barrier. PART B - SURFACE DRESSING (mechanised)4.3 EXECUTION OF THE WORKA surface dressing is usually applied to half the width of the road at a time. There are seven steps: 1. Sweep the complete road surface where the binder is to be applied so that it is perfectly clean(a).2. Mark out the road surfaceA string-line is run along the edge of the carriageway where work starts to ensure good alignment of the edge of the surface dressing (b). 3. Check and adjust the binder distributor Off the road:  check the temperature of the binder (Refer to thechart on Page III - 143, or other guidelines).  check that all the spray bar jets are operating properly (c). Use split oil drums to collect binder. III -143PART B - SURFACE DRESSING (mechanised)Spraying temperatures forbindersCUTBACK GRADES (US ASPHALT INSTITUTE)WHIRLING SPRAY JETSSLOT JETSMIN °CMAX °CMIN °CMAX °CMC 3050604050RC/MC 7065805570RCIMC 250951158090RC/MC 800115135105115RC/MC 3000 135150120130PENETRATION GRADES400/500 160 170140150280/320 165 175150160180/200 170 19015516580/100 180 200165175NOTE:Because of the inflammable nature of the solvent used in RC- type cutbacks, application temperatures for RC grades shouldbe restricted to the lower pails of the ranges given above.Attention is also drawn to the need to extinguish flames and prohibit smoking when heating, pumping or spraying all cutbacks. Fire extinguishers should always be readily at hand. III - 145PART B - SURFACE DRESSING (mechanised) On the road: adjust the height "h" of the spray bar soeach point of the road is sprayed by binder from three separate jets,  adjust the angle of the spray bar so that it isparallel to the road surface to obtain a good transverse distribution of the binder (d), adjust the width covered by the spray bar sothat 1/3 of the spray coming from the last jet on the spray bar overlaps the centre line of the road. This will ensure that the correct amount of binder will be deposited along the centre of the road following the second pass of the binder distributor (e). Carry out a rate of spread test for the bitumendistributor and provide a driver's chart (rate of spread calibration).  The second pass of the distributor on the other lanemust take place in the same direction. PART B - SURFACE DRESSING (mechanised)4Place strips of strong paper in position toensure regular transverse joints at the beginning and end of each pass of the distributor. The length "L" of each pass will be determined by the number and capacity of the gritting lorries (see the typical values given in the table shown opposite).5Distribute the binderThe binder must only be applied to a completelydry surface (application of surface dressing during the rainy season should therefore be avoided if possible). PART B - SURFACE DRESSING (mechanised) position the distributor 10 to 15 metres from thebeginning of the surface that is to be treated and line it up with the marked outer edge of the road (f), advise the driver of the speed at which he is to check gates on the gritting lorries.The distribution of the binder can now start providingthat the gritting lorries and the roller are ready for immediate operation. NOTE:This should be obtained from the driver's chart or alternativelyfrom the technician responsible. III - 151PART B - SURFACE DRESSING (mechanised)The distributor jets are opened over the first strip ofpaper and closed over the strip at the end of the run (g). A test of the rate of spread of bitumen should be carried out during the spraying operation. No person or vehicle must be allowed onto the surface sprayed with binder.6Distribute the AggregateThe aggregate is distributed by driving thegritting trucks backwards (h) as follows:  for the first half-width of the road, aggregateis spread over the binder leaving a 20 cm strip uncovered along the centre line (i), PART B - SURFACE DRESSING (mechanised) for the second half-width of the road,aggregate is spread over the remaining width of the binder including the strip left un-covered. Any adjustments to gritting width are made by opening or closing the appropriate tailgate flaps. If the sprayed width is wider than the full truck gritting width, then a second gritting truck must followimmediately covering the rest of the binder.The distribution of the chippings is startedimmediately after the application of the binder such that the distance between the binder distributor and the gritting truck never exceeds 75 metres (preferably 30 metres).Following the initial passage of the gritting truck,check that the complete surface has been covered with aggregate adding additional stone by hand if necessary, and then: -use brooms to sweep back any aggregate that may have fallen onto the uncovered strip of binder or beyond the edge of the road (j), -remove the strong paper laid at the beginning and end of the road section being treated (k). PART B - SURFACE DRESSING (mechanised)7Roll the DressingRolling is carried out using two rollers runningbackwards and forwards at a distance of at least 50 metres from the gritting trucks at speeds of not more than 8 km/hr. A number of passes (usually 5) of the rollers should be made over the complete surface. When the rolling has been completed, providing itdoes not rain, the treated section of road is openedTo do this remove: the traffic barrier, the traffic cones, using vehicle with headlights to warn oncoming traffic and to protect workmen. If traffic discipline is poor, convoy vehicles can beused to restrict speed for the first 2 hours.IMPORTANT NOTE: At the end of the day, the surface dressing must be completed over the whole width of the road section. All spraying equipment and tools must be thoroughly cleaned at the end of the day Spray bars and nozzles should be flushed out with diesel. PART B - SURFACE DRESSING (mechanised)4.4COMPLETION AND REMOVAL OFTEMPORARY SIGNPOSTING The road is left open to traffic at the end of the day leaving the following signs in place at the ends ofthe treated section of road: "50 km/hr Speed Limit" sign, "Loose Chippings" sign. III - 159PART B - SURFACE DRESSING(mechanised)Finishing work is carried out during the weekfollowing the application of the surface dressing.There are four activities required:1 Place the traffic signs in position The following traffic signs must be placed on the shoulder for both directions of traffic:  "Men Working", "Loose Chippings",  "No Overtaking",  "50 km/hr SpeedLimit",At the end of theroadworks, "End of Speed Restriction".If traffic is heavy, barriers, cones and traffic controlshould also be used. III - 161PART B - SURFACE DRESSING (mechanised)2 Remove excess material as soon as possibleExcess chippings are removed by sweeping lightly by hand or with a mechanical broom. If left on the roadthey can damage vehicles and shatter windscreens.3 Sand any areas where bleeding* has occurredThis is done by throwing coarse sand over the affectedareas (Page III - 51).4 Remove the traffic signsAll traffic signs are removed on completing the finalwork.*See List of Terms, Volume I. TYPICAL WORK REPORTSURFACE DRESSINGWork Report No: . . . . . . . . . . . . . . . . . Date: . . . . . . . . . . . . . District:........... .......……………... Road No:.............……….Section: . . . . . . . . . . . from km . . . . . . . . . to km . . . . . . . . .. .AGGREGATE STOCKPILE:Location: . . . . . . . . . . . . . . . . . . . . . Haul Distance: . . . . . . . SURFACE DRESSING: Length: . . . . . . . . . . . . WORKING TIME: from: ..........to: .......……………Width:.................Area:………………..Reasons for stoppages: . . . . .. . . .WEATHER: SunnyCloudy Rain 0 CHIPPINGS: 2 - 6mm / 4 - 6mm / 6 - 10mm / 10 - 14mm/ . . Sources of Supply: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BINDER: Type: ..................Viscosity: Temperature: On arrival: ..........Source: .. . . . On emptying tank: . . . . . . . .. . .WORK: Single seal / Double seal / Double Chipping LayerRate of Spread:BinderRate of Spread:Chippingsistlayer ....................2nd layer . . . . . . . . . . 1 st layer . . . . 2ndlayer .................... (Separate manpower and equipment reports) COMMENTS:Foreman:......................................Date:...................kg/m2kg/m2 .... I/m2. . I/m2 PART B - SURFACE DRESSING (mechanised)4.5 WORK REPORT The report must be filled in each day, detailing: the work carried out, the resources used. III - 165Part CRESEALINGOPTIONS III - 167PART C - RESEALING OPTIONS1. THE OPTIONSMechanised SURFACE DRESSING, described inPart B, is the most common type of treatment for the PERIODIC MAINTENANCE reseal of a bituminous pavement. However, in certain circumstances the maintenanceneeds or available resources make other resealThese optionsare: LABOUR BASED SURFACE DRESSING FOG SPRAY* SLURRY SEAL*Although the planning, procedures and safetyrequirements for these alternative treatments are similar to those for SURFACE DRESSING, this Part of the Handbook describes the principal differences. For all common arrangements, such as traffic andsafety measures, refer to Part B.*See List of Terms, Volume I. PART C - RESEALING OPTION:2. LABOUR BASED SURFACE DRESSINGIn remote locations, for limited areas (such as shoulders)or when the specialist equipment is too expensive or is not available, surface dressing may be carried out by labour based methods. The quality of work will be just as good as by mechanised methods if the works are properly managed. Labour based surface dressing may be carried out using bitumen emulsion or cut back bitumen. Materials specifications are the same as for mechanised surface dressing. The activities that need particular attention are:  heating and temperature control of the bitumen when cut back bitumen is used.  applying the bitumen at the correct rate of spread.  complete coverage of the binder by the chippings before the binder cools/breaks.Up to 800 m2 per day of labour based surfacedressing can be achieved by one crew. PART C - RESEALING OPTIONS2.1 RESOURCES REQUIRED Personnel 1 foreman, 1 bitumen heater operator,  1 - 2 bitumen layers/spray lance operators,  squeegee operators,  drivers,  2 traffic controllers,  4-6 workmen. Plant and Tools 1 bitumen heater and towing/carrying vehicle, 1 spray lance if available,  1 truck for transporting aggregates,  1 light vehicle for supervision and general duties,  1 bitumen thermometer. PART C - RESEALING OPTIONS Small Items of Equipment 2 wheel barrows, shovels,  pickaxes,  2 rakes,  brooms,  watering cans or other bitumen dispensers,  squeegees. Tools and Supplies 1 drum of diesel oil for use in cleaningthe tools and equipment,  rags,  number of paint brushes,  2 metal buckets,  chalk, or paint for marking,  stringlines. PART C - RESEALING OPTIONS2.2 HEATING THE BINDER(for cut back bitumen)The binder will normally be delivered to site indrums. It should be decanted into a suitable bitumen heater which may be: towed, static, or  vehicle mounted.The heating may be carried out by: diesel burners, wood,  coal or other fuel.If necessary the specified amount of dieselshould be added to achieve the required viscosity of cutback. Care must be taken to ensure that the materials:  are well mixed,  are not overheated.It is IMPORTANT to use a bitumen thermometer.Bitumen application temperature ranges are shown on Page III - 143. PART C - RESEALING OPTIONS2.3 USING BITUMEN EMULSIONIf bitumen emulsion is used as the binder it will notnormally require heating*. Emulsions consist of bitumen droplets mixed with water in such a way that, when applied, the water evaporates leaving the bitumen to "break" and to perform as a normal penetration grade. The choice of emulsions should be made with regard to the type of stone being used and reference to the suppliers. It should be noted that bitumen emulsions have a limited storage life. They should normally be used within 6 months of purchase. Drums should be rolled to mix the contents thoroughly before use.*Cationic emulsion will need to be heated PART C - RESEALING OPTIONS2.4 SETTING OUT THE WORKRobust containers, such as watering cans, must beused for carrying and applying the hot cut back or emulsion to the road surface. Each container must have a fixed volume mark of known quantity. The area of road to be covered by one container can be calculated using the specified rate of spread of binder. To achieve the length of road to be covered by one container divide the volume by the width of road to be sealed and the rate of spread. Using stringlines, mark the cleaned area of the road surface with chalk for each container of binder. III - 181PART C - RESEALING OPTIONS2.5 APPLYING THE BINDERWhen the binder has reached the requiredtemperature it is poured into the containers and carefully carried to the placement site*. Emulsions will normally be used directly from the drums after thorough mixing. The binder is poured over the marked area as evenly as possible. The squeegees are used immediately to ensure even distribution. The personnel handling hot bitumen must be supplied with protective clothing and footwear. If a hand lance is available this may be used to apply the binder. However practice and skill are required to evenly apply the correct amount of binder. *Beware of the build up of cold bitumen on the inside of thecontainers. III – 183PART C - RESEALING OPTIONS2.6 APPLYING THE CHIPPINGSThe chippings should be applied as soon aspossible after the binder is distributed.This may be done by: spreading the chippings by hand from stockpilespreviously placed on the road shoulder,  casting the chippings by hand from the rear of a truck reversing slowly over the previously laid stone. Care must be taken to ensure as complete a coverage as possible without over applying chippings. Workmen can follow up with a wheel barrow to top up areas where the chippings are spread too thinly. The finished work is carefully rolled with the empty chipping truck as soon as the chippings are spread. PART C - RESEALING OPTIONS3. FOG SPRAYA fog spray is a very light film of binder which issprayed onto a "dry" or "hungry" road surface to bind together and hold in place stone particles that otherwise would be picked off by traffic. Typically a fog spray is used to help retain chippings on a new surface dressing that may be poorly held for some reason, or to enrich the surface of an old and lean bituminous surface. The binder used is normally a bitumen emulsion, which should be sprayed at a rate of 0.7 to 0.9 kg/m2 (for a 60 percent emulsion), to achieve a residual bitumen application of 0.4 to 0.6 kg/m 2 . Where "pick up" of the binder by vehicle tyres is likely to occur, the surface may be blinded with a light sprinkling of fine sand or crusher dust. PART C - RESEALING OPTION:4. SLURRY SEALIn this process a fine, graded, aggregate is mixed atambient temperature with water, dope (an additive) and a bitumen emulsion, having a relatively high bitumen content. Some cement is also usually added. The mixture is applied to the road surface as a free- flowing slurry in a layer 5 mm to 10 mm thick. The mixture penetrates and seals surface voids and cracks very effectively; hence the process is particularly well suited to the maintenance of old bitumen surfaces. Slurry seals may not resist reflection cracking in asphalt concrete surfacing. When the emulsion "breaks" an impermeable bitumenrich surface results. The skid resistance of such a surface can be rather low and hence slurry seals are often used as a second treatment on top of a single surface dressing. In this way the tops of the chippings will penetrate through the slurry seal and provide skid resistance. The slurry holds the chippings very securely and provides a durable,impervious and non-skid surface. Slurry seal machine; (diagrammatic) PART C - RESEALING OPTIONSThe aggregates used in slurry seals are normallynot greater than 6 mm in size but some specifications include material up to 10 mm in size. Slurry seals can be made with simple, slow breaking, (stable) anionic emulsions in a static mixing plant (such as a cement mixer) and then spread on the road by hand or by simple drag spreaders. However, the normal technique is to use mechanised mixer/spreader units which enable faster breaking cationic emulsions to be used. These units are self-propelled and have storage capacity for the bitumen emulsion, the aggregate, the cement and water. One machine can spread approximately 8,000 m2 of slurry seal per day. When spread the slurry needs little, if any, compaction and on a busy road, traffic compaction alone will suffice once the emulsion has "broken". On lightly trafficked roads a pneumatic-tyred roller should be used. In heavy traffic, where the road cannot be closed for long, chemical agents may be incorporated in the slurry to control the "break" of the emulsion so that traffic can pass over the new slurry seal within 20 to 30 minutes of laying. Mechanised slurry sealing is normally carried out by a specialist contractor. The Road Authority should set a specification for slurry seal mixing and laying. Part DTHIN OVERLAYS III - 193PART D - THIN OVERLAYS1. THE TASKOVERLAYING is normally a PERIODICMAINTENANCE or IMPROVEMENT activity.1.1 APPLICATION Thin overlays applied over large areas can beused to:  fill small surface deformations which areuncomfortable and dangerous to traffic,  improve insufficient surface texture which is dangerous for traffic,  seal permeable surfaces which allow water to penetrate the base and causedeterioration. They are usually more durable than surfacedressings.  Overlays are usually applied to important roads with heavy traffic and high speeds.  When deformation is severe, the overlay work must be preceded by the levelling of depressions and ruts, and repairs to potholes (Volume III, Part A).  This work may also be accompanied by the restoration of shoulders and ditches (see Volume I).  Overlays must be applied during dry weather. III – 195PART D - THIN OVERLAYS Thin overlays must NOT be applied to aseverely cracked pavement without a detailed pavement investigation.  Thick overlays (more than 5 cm) which add substantially to the strength of the pavement, require detailed investigation and design, and are outside the scope of this Handbook. However many of the guidelines are also applicable to thick overlays.NOTE: Overlay works are normally carried out by contract PART D - THIN OVERLAYS1.2 DIFFERENT TYPES OF THIN OVERLAY Overlays always consist of hot plant mixed bitumen coated aggregate and a bituminous binder.Thin overlay types are:(Aggregate size):0/50/6 to 0/12 0/6 to 0/12bituminous mortarsbituminous macadams bituminous concretes They are spread by a paving machine in a singlelayer of maximum thickness:  cm for bituminous mortars, cm for bituminous macadams and bituminous (asphaltic) concretes.  Plant mixes are sometimes known as asphalts*.*See List of Terms, Volume 1. PART D - THIN OVERLAYS2. DEFECTSDefects requiring thin overlay treatment generally involvefairly large areas. These defects can concern:  the surface:  wear (glazing*, cracking*, streaking*)  surfacing failure (cracking),  excess binder (bleeding the pavement structure:- minor deformation (0 - 10 mm).*See List of Terms, Volume I. PART D - THIN OVERLAYS3. RESOURCES3.1 PERSONNEL Site Work 1 foreman, 1 overseer for traffic control,  1 overseer for the works,  1 spray bar operator,  1 payer attendant,  2 traffic controllers,  2 labourers for spreading,  2 labourers for finishing. Plant Operators and Drivers 1 mechanical broom operator, 1 bitumen distributor driver,  1 payer operator,  1 steel wheel roller operator,  1 rubber tyred roller operator,  1 driver for each tipper truck,  1 night watchman,  1 light vehicle driver. PART D-THIN OVERLAYS3.2 PLANT AND TOOLS 1 mechanical broom, 1 binder distributor with working thermometer,  1 payer/finisher,  1 rubber tyred roller,  1 steel wheeled roller (6 to 8 tonnes),  tipper trucks as necessary to keep payer supplied,  1 light vehicle,  bitumen thermometer for premix material.  small items of equipment (see Part B, Page III - 109), hand tools and supplies (see Part B, Page III -109).  tarpaulins to cover premix material during transportto the site.III - 203 PART D - THIN OVERLAYS3.3 MATERIALSIt is important to be aware of the:  materials used for producing the plant mix,  different types of plant mix,  binder content,  materials required for the application.III - 205 PART D - THIN OVERLAYSMATERIALS USED FOR PRODUCING THE PLANT MIXThese are: aggregates constituting the "mineralframework", bituminousbinder.Aggregates (fines, sands, stone) Fines (or fillers) (a) mineral powders from soundrock. A fraction of the fines can consist of cement or lime in certain cases. Sands (b): fine (dune, sea, river or pit sand), coarse (most often from crushing). Stone (c) crushed hard rock sieved to conform toa grading in the following range: retained on a 2, 4 or 6 mm sieve and passing an 8, 10 or 12 mm sieve.Bituminous binderA penetration grade bitumen (d): usually one of80/100, 60/70 or 40/50. 60/70 bitumen is usually preferred however 80/100 is more commonlyavailable.III - 207 PART D - THIN OVERLAYSDIFFERENT TYPES OF PLANT MIXThere are three broad classes ofmixes: bituminous mortars  bituminous macadams  bituminous concretes(a) (b) (c)Bituminous mortars consist of a mixture of: fines (or fillers), one or more sands, bituminous binder.Bituminous macadams and bituminous concretecomprise in addition, one or more sizes of stone.Bituminous concretes are surfacings of the highestquality and meeting the strictest specifications.NOTES: The thickness of the overlay must not be less than 2.5 cm, and should be at least 1.5 times the maximum stone size.  Bituminous macadams may be either dense or open mixtures III - 209 P =PART D -THIN OVERLAYSBINDER CONTENTThe binder content of the plant mix is given by weight of bitumen x 100 total weight of mix This varies for each mix type with: § the fines content, § the grading.Binder contents are given below:Type of Plant MixBinder Content "p" bituminous mortar (a) 6 - 10 bituminous macadam: (b) dense4 - 7 Open4 - 5 bituminous concrete: (b) 5 - 8 TACK COAT BINDERCLASS (p.lll -117)TYPICAL RATES OF SPREADCUT BACK50/100 - 150/200BITUMEN400/600 - 1001250- MEDIUMCURING0.1 kg/m2- RAPIDTOCURING 0.4 kg/m2COAL TARRT4 TO RT9BITUMEN65 TO 70EMULSION PART D - THIN OVERLAYSMATERIALS REQUIRED FOR THE APPLICATION Tack Coat(a)The binder to be employed may consist of: a rapid or medium cut back bitumen (hot),  a tar (hot),  a rapid breaking bitumen emulsion (hot or cold)". The amount of binder to be used depends on the condition of the surface. The main types of binder together with the average rates of spread are listed in the table opposite.  Plant Mix(b)*Cationic emulsion will need to be heated. III – 215PART D - THIN OVERLAYS3.4 SIGNS AND SAFETY EQUIPMENTApply the recommendations of Part B (Pages III - 121 and III - 123) with the following amendment:  Traffic Control Equipment (the "Loose Chippings" sign is not needed for this operation). TYPICAL WORKSHEETTHINOVERLAYSWorksheet No: . . . . . . District: . . .PREPARATORY WORK:Potholes LIDepressions .........................Date:. . to km: . . . . . . width . . . . . . . mEdge damage 0TACK COAT:Border: . . . . . . . . . . . . . . . . Rate of spread: . . . . . . . . . . . . . . . kg/m2OVERLAY:Binder: .................................................. Aggregate:............................................... Coverage: ...........................................................................................kg/m2 Nominal thickness: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . cmMinimum laying temperature: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . °CLOCATION OF MIXING PLANT:Haul distance: . . . . . . . . . . TRANSPORT: . . . . . . . . . . .................time:.....................trucks: III - 217PART D - THIN OVERLAYS4. MAINTENANCE METHODSIt is essential to properly plan, prepare andorganise overlay activities to achieve successfulresults.4.1 PRELIMINARY TASKSThere are four preparation activities: 1 Refer to the Work SheetThis contains all the information needed to plan andorganise the work. III - 219PART D - THIN OVERLAYS2Equipment CheckOne week before start of the work a checkshould be made to ensure: that all the equipment required is available andin good working order, that arrangements have been made for fuelfor the equipment, and its maintenance,  that all personnel are available (Page III - 201), III - 221PART D-THIN OVERLAYS that hand tools and traffic signs areavailable, that there is sufficient transport for the premixed materials, to ensure a continuous layingoperation. PART D-THIN OVERLAY3 Check that the preparatory work has been properly carried out The success of the thin overlay depends on the preparation of the existing surface by the routine maintenance gang (see Part A).One week before the overlay the following must bechecked:  that all potholes have been repaired (see Part A),  that road edges have been repaired (see Part A).  that the existing surface is clean and free of dirt, orother debris that would affect the bond of the new surfacing (clean it if necessary).III - 223 PART D - THIN OVERLAYS4 Organise the WorkThe day before work starts the foreman must: inspect the condition of the existing surface for the last time to ensure that it is clean and has been properly repaired.  assess the likelihood of good weather. check with the person in charge of the mixingplant that he will be able to supply the site and check the timetable for the start and end of the mixing operation.  check the route that will be used by the supplytrucks between the mixing plant and the site and note the probable time for the journey.III - 225 PART D - THIN OVERLAYS send to the site: the mechanical broom, the payer finisher,  the rubber tyred roller,  the steel wheeled roller (and ensure a water supply for it), signs and safety equipment. arrange a night watchman for the equipment thatis left overnight and ensure that correct traffic signs are erected to safeguard any equipment left on the road. Equipment can be left:  off the road (a) - this is preferable as it issafer for both the road users and the equipment,  at the roadside (b), ONLY if proper warning signs are provided (Page III - 229).III - 227 PART D-THIN OVERLAYS4.2 TEMPORARY SIGNPOSTINGTraffic signs conforming to the regulations mustbe correctly placed before starting any work. This is to ensure the safety: of the roadusers, of the personnel working on the site,  of the vehicles and equipment to be used onThe traffic signs must be located: ahead of the worksite (in both traffic directions)to give advance warning of danger,  along the length of the roadworks to protect the site from traffic when it is not possible to build a diversion,  at the end of the roadworks as an indication thatthere is no further restriction.Details of signs to be used and their locations aregiven in Part B, Pages III - 136 to 139. The "Loose Chippings" signs are not required. Flashing warning lights must be used if any part ofthe carriageway is closed off overnight.III - 229 III - 231PART D - THIN OVERLAYS4.3 EXECUTION OF THE WORKOverlays are generally laid over half the width of thecarriageway at a time.There are eight steps:1 Sweep the SurfaceSo that it is perfectly clean before laying the tackcoat.2 Mark the CarriagewayA stringline is run along the edge of the carriagewaywhere work starts to ensure good alignment of the edge of the tack coat. PART D-THIN OVERLAYS3 Apply the Tack CoatMaking sure that the carriageway is dry, use thedistributor to spray half the width of the road observing all the precautions and provisions described on Pages III - 141 to 151. Working from the rate of spread specified in the work sheet, inform the distributor driver of the speed to be observed. If a vehicle mounted bitumen distributor is not available the tack coat may be applied by hand asdescribed in Part C.NOTE:The overlay material should not be placed too soon after the tack coat, as this will prevent the break of the emulsion orevaporation of the cutting agent in the cut back.Traffic must not be allowed to dove on the tack coat.III - 233 PART D - THIN OVERLAYS4 Set up the guide system for the paverThe payer works with its adjusting screws set so that the material can be placed in a layer of constant thickness. It follows the stringline at the edge of the first half of the carriageway. 5 Prepare the equipmentThe payer is set up to spread the plant mix overhalf the width of the carriageway. The paver finisher:Check the screed plate* to ensure it is clean toavoid defects in the surfacing. It must also be heated so that the material does not stick at the start of spreading, *See List of Terms, Volume I.III - 235 PART D-THIN OVERLAYSadjust the height of the screed plate by placingspacer blocks of thickness "e",ensure that the hopper* of the payer is clean, dryand contains no cold material.6 Placing the mixIn the case of rain, work must be stopped.When the tipper trucks are backing onto the paver, care must be taken that they do not bump it,*See List of Terms, Volume1.III - 237 PART D - THIN OVERLAYSensure that the material is not spilled whilst thehopper is being filled,place the truck's gear lever in neutral so that it canbe pushed by the payer until its body is empty,ensure that in addition to the tipper truck supplyingthe payer, the next truck is waiting so that the payer can work continuously.When an emulsion tack coat is used the mix mustnot be laid before the emulsion breaks.III - 239 BINDER(°C)MINIMUMPLACING TEMPERATUREBITUMEN 80/100125BITUMEN 60/70130BITUMEN 40/50135 III - 241PART D - THIN OVERLAYSThe temperature of mix:The table opposite shows the minimum temperature ofthe mix (in the hopper) when it is laid.Check mat thickness:Check the thickness of the uncompacted matregularly with a probe and adjust the payer screedplates if necessary.7CompactionInitial compaction is carried out with the rubbertyred roller (see Note Page III - 247). Using this machine it is important to:  check that the tyres are clean to avoid picking up the asphalt from the surface (a),  check the tyre pressures which must all be thesame and equal to 6 kg/cm2 when warm (b). PART D - THIN OVERLAYSFor good compaction, the roller must: work as close to the payer as possible,  be operated with its driven wheels closest to the paver.Make parallel passes beginning: for the first half of the carriageway at the edge (a),  for the second half of the carriageway at the centreline (b).Each compacted strip must partially overlap thepreceding one.III - 243 PART D - THIN OVERLAYSAt the end of a pass, speed is gradually reduced sothat the roller can reverse without jerking.The second stage of compaction, is carried out with a6-8 tonne steel wheel roller (see Note Page III - 247). When using this machine:  check that the rollers are clean to avoid marking the surface (a),  Insure that the spray system contains water and is in working order (b).For good compaction, the roller must work: as close as possible to the rubber tyred roller,III - 245 PART D - THIN OVERLAYS make parallel passes beginning:for the first half of the carriageway at the edge (a),for the second half of the carriageway at the centre line (b).At the end of each pass, speed is gradually reducedso that the roller can reverse without jerking. Compaction must be completed before the materialcools too much.NOTE:For each roller, the number of passes needed depends on the type of material and the thickness of the layer. the number will be determined by the engineer. However all traces left by the rubber tyred roller must be removed by the steel wheel roller. Compaction trials should be carved out at the start of each overlay job. III- 247 PART D - THIN OVERLAYS8 JointingJoints should be made with care. A joint willaffect: the impermeability of the surface, the durability of the overlay,  the finished appearance and roughness of the road. The longitudinal joint The correct procedure is asfollows: spread the material on the second half of thecarriageway while the material on the first half is still hot,  rake back in a straight line any excessmaterial spilled on the first half of the road when laying material on the second half,  compact the second half of thecarriageway covering the whole joint area.III - 249 III - 251 PART D-THIN OVERLAYS The transverse joint*The correct procedure is asfollows: remove a strip of compacted materialabout 1 metre wide with a neat verticalcut, before restarting work, place a block ofequal thickness to the amount of compaction settlement between the screed plate and the compacted surface,  compact the joint over a length of 30-40cm with the steel wheeled roller, workingbackwards.9 Checks the transverse slope is checked using astraight edge and spirit level,  the other material tests should be carriedout by the laboratory technicians. * See List of Terms, Volume I. PART D - THIN OVERLAYS4.4COMPLETION AND REMOVAL OFTEMPORARY SIGNS As soon as the overlay has been completed.There are two activities required:1 Clean the work areaEach day before moving the traffic signs, it isnecessary to remove all excess material left overafter making the transverse joints.2 Provide RampsWhere the overlay will be used by traffic betweenworkdays, temporary ramps must be provided at the end of each day's work. This is done by tapering out the overlay mat over a distance of 10-20 cm. These ramps must be cut back to a transverse joint (see Page III -250) before work restarts. At the completion of the works, the overlay must be smoothly run into the existing road surface byexcavating the existing surface and replacing it withIII - 253 PART D - THIN OVERLAYS At the end of each day, the road is opened totraffic, but the following signs must be retained at the ends of the new section:  "Men Working" sign,  "50 km/hr Speed Limit" sign,  "End of Restriction" sign. When all work has finished, the road is opened totraffic without restriction. All the signs are then removed in the following order:  the traffic barriers,  the traffic cones, using vehicle with headlights to warn oncoming traffic and to protect workmen,  the two "End of Restriction" signs,  the two "Speed Limit" signs,  the two "Road Narrows" signs,  the two "No Overtaking" signs,  the two "Men Working" signs.III - 255 TYPICAL WORK REPORTTHIN OVERLAYSWork Report No: . . . . . . . . . . . . . . . . District: . . . . . .Date: ..................... ..................................................Road No: .tokm:.................... TACK COAT: Binder: ..................................................Total Area: . . . . . . . . . . . . . . . m x . . . . . . . . . . . m = . . . . .Quantity used: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Rate of spread:PLANT MIX: Type: ........... Total area: . . . . . . . . . . . . . . . m x . . . . . . . . . . . m = . . . . . Quantity used: ...................................... Rate of spread:WEATHER:Sunny 0Cloudy El Rain El(Separate manpower and equipment reports)COMMENTS:Foreman:................................................Date:........................ m2 tonnes kg/m2 ... m2 tonnes kg/m2 PART D - THIN OVERLAYS4.5 WORK REPORTThe report must be filled in each day by the foreman detailing: § the work carried out, § the resources used.III - 257 III - 258 Notes and SketchesIII - 259 User of this Handbook:NAME……………………………………………ADDRESS………………………………………………………………………………………………………………………………………………………………………………………………………DATE……………………………………………III - 260 III - 261ACKNOW LEDGEMENTSThe contents of this handbook draw on many sources,past and present, and it would be impossible to acknowledge them all individually. Much of the material is an updating of the UN/ECA Maintenance Handbook for Africa, compiled by experts from France, Germany and the United Kingdom, and published in 1982. Its three volumes encapsulated the broad experience of highway engineers, maintenance managers, consultants and researchers from many different countries. The present revision was undertaken by Mr R.C. Petts of Intech Associates, in close association with the Overseas Centre of the Transport Research Laboratory. The work was funded by the UK Overseas Development Administration and supported and guided by a subcommittee drawn from the PIARC Committee on Technology Transfer and Development (C3). It benefited from the collective wisdom of that committee and the countries represented within it. These included Australia, Algeria, Belgium, Brazil, Burkino Faso, France, Germany, India, Italy, Morocco, Poland, Portugal, Senegal, Spain, Turkey, the United States of America, the United Kingdom and the World Bank. On behalf of the subcommittee I would like to record our sincere thanks to all those who contributed, in whatever way, to the production of this second version of the Maintenance Handbook and to making it more valuable to a wider international audience. I am sure it will fulfil its intended purpose of strengthening the capabilities of maintenance workforces and giving them a stronger sense of professional pride in the vital work they are doing. ACKNOWLEDGEMENTS continuedAny revision of this kind is an ongoing process, andcomments or suggestions for further improvements should be made known to the PIARC Central Office at 27 rue Guenegaud, 75006, PARIS, France.Fax: +33 (1) 46 33 84 60. J. Stuart YerrelChairman, Subcommittee C3-6dIII - 262 WHAT IS PIARC?Founded in 1909 following the 1St International RoadCongress held m Pans in 1908, the Permanent International Association of Road Congresses (PIARC) is the oldest of the international associations concerned with roads and road engineering. The general aim of the Association is to improve international cooperation and to foster progress in.  the formulation of road transport policies,  the planning, construction, improvement and maintenance of roads,  the operation and management of road systems, within the context of wider policies towards transport.To achieve these aims PIARC: organises a World Road Congress every four yearsand various technically oriented events,  creates and co-ordinates Committees,  publishes a number of documents including a periodical bulletin. It is assisted in its task by National Committees. PIARC is a non political and non-profit association. It was granted consultative status, category II, to the Economic and Social Council of the United Nations m 1970. The official languages of PIARC are French and English There are several categories of members: Governments, regional authorities, public bodies, collective members and individual members. As of 1 January 1994, PIARC has 72 member Governments and 2,100 members m 100 countries. PIARC has strong links with several regional organisations and is in favour of networking between countries dealing with similar questions. PIARC may help to create and/or develop such networks.III - 263 PIARC Committees and Working Groups are composedof engineers and experts appointed by member countries They act on a continuous basis between each Congress and participate m international meetings dealing with subjects within their competence. On average they hold two plenary meetings a year. As of 1 January 1994, Committees and Working Groups gather approximately 700 engineers and experts from 40 countries. Thirteen Committees and four Working Groups are active (period 1991 -1995). COMMITTEESC1 - Technical Committee on Surface Characteristics C3- Committee on Technological Exchanges and Development C4- Committee on Interurban Roads C5 - Committee on Road Tunnels C6- Committee on Road Management C7- Technical Committee on Concrete Roads C8 - Technical Committee on Flexible Roads C9 - Economic and Finance Committee C10 - Committee on Urban Areas C11 - Committee on Road Budges C12 - Technical Committee on Earthworks, Drainage, Subgrade C13 - Committee on Road Safety C14 - Committee on the Environment WORKING GROUPSG1- PIARC Winter Road CongressG2- Natural Disaster Reduction G3- Modern Traffic Control and ManagementG4- Heavy Freight Vehicle Issues PIARC PUBLICATIONS - Committees and WorkingGroups publish synthetic documents, recommendations and state of the art. These documents, intended for decision makers, design and field engineers and researchers, are based on wide international consensus. CONGRESS DOCUMENTS - The documentspublished on the occasion of World Road Congresses are an invaluable source of information and experts agree on the fact that they are most interesting and unique.PERIODICAL BULLETIN "Routes/Roads" - TheAssociation Bulletin was issued for the first time in 1911. It features comprehensive files on road matters in various countries, articles written by members of Committees and Working Groups and news of interest to the world road community. Its issues of a hundred pages are published three to four times a year.TECHNICAL DICTIONARY OF ROAD TERMS ANDLEXICON -The first edition of the DICTIONARY was issued in 1931. The sixth edition (French/English) was published in 1990. The Dictionary is published with the financial support of UNESCO and is translated into eighteen languages: Arabic, Chinese, Croatian, Czech, Danish, Dutch, German, Greek, Hungarian, Italian, Japanese, Lithuanian, Polish, Portuguese, Romanian, Russian, Spanish and Slovak. The Lexicon contains over 12,000 expressions in English and French and is also available on computer disk. All these documents are published in French andEnglish. PIARC publications catalogue is free ofcharge and can be ordered through:ANRTP32, rue du March commun Centre de Gros - Case postale 1220 44082 NANTES Cedex 03 (FRANCE) Fax: +33 40 50 13 64III - 265 WHERE TO ORDER THE HANDBOOK The English version of Volume I:Maintenance of Roadside Areas and Drainage Volume II:Maintenance of Unpaved Roads Volume III:Maintenance of Paved Roads Volume IV:Maintenance of Structures and Traffic Control Devices may be ordered from: Transport Research Laboratory Crowthorne, Berkshire RG11 6AU United Kingdom The Road Maintenance Handbook is also being published in French, Spanish and Portuguese. Other languages are under consideration. For more details, please contact PIARC Central Office - 27 Rue Guenegaud, 75006, PARIS, France. Fax: +33 (1) 46 33 84 60.Panted by:- Borough Press (Wiltshire) Ltd, SN2 6YW, UKIII - 266