Maintenance of Roads [ All you need to know]

Introduction to Road maintenance

Maintenance of roads is an intervention measure designed to arrest the deterioration of a road and to restore the service condition to the as-built state or, at least, very nearly so. The type and scale of the maintenance activity will depend on the type of pavement failure being considered.

Types of road maintenance

There are two types of road maintenance works:  routine and periodic maintenance

a. Routine Maintenance

This is the work that is performed as needed throughout the year and includes the day-to-day maintenance of the road. Routine maintenance activities are carried out independent of the level of traffic on the road.

If routine maintenance is neglected or not done properly, or money diverted to other maintenance categories, the condition of the road will quickly deteriorate.  The following activities listed in Table 9.1 are routine maintenance activities.

Paved Roads Unpaved Roads
Grass cuttingGrass Cutting
Pothole patching Pothole patching
Repair of depressions, ruts, corrugations Dry Grading without compaction
Edge Failure repairs Wet Grading with compaction
Crack sealing Spot improvement
Grading gravel and high shoulders Ditch cleaning
Refilling of shoulder drop-offsCulvert de-silting
Spot improvement Cleaning, repairing and repainting of signs
Ditch cleaning
Culvert de-silting
Cleaning, repairing and repainting of signs
Types of Routine Maintenance Activities

a. Periodic Maintenance

This is the work required only over a long period of time or once every few years to preserve the structural integrity of the road. 

If routine maintenance of roads is undertaken at the right time and effectively, periodic maintenance may become warranted after a very long time.

The table below contains the list of activities classified as periodic maintenance.

Paved Roads Unpaved Roads
Resealing Re-gravelling
Resurfacing Rehabilitation
Rehabilitation Upgrading
Types of Periodic maintenance Activities

Condition survey

In order to assess the maintenance needs of a road, it is necessary to undertake a condition survey.

The survey involves visual inspection of the condition of the pavement and the rating of the condition. The rating of the pavement condition is based on the pavement’s distress features such as cracks, potholes, fretting, spalling, raveling, pavement surface distortions, edge failure, patched up areas, etc.

The survey will include a description of the characteristics and attributes of the defects in terms of location, type, extent or severity level, position on the road, and spacing. 

The recognition of defect types and their severity is helpful in determining the degree to which the current condition of a road departs from the acceptable standard and in determining where and when an intervention activity may be needed and the maintenance activity for remedying the distress. 

For pavements that need structural strengthening, it is based on the condition survey that a structural evaluation or survey program may be drawn up for execution.

Maintenance management

In order that a network of roads will be effectively and efficiently maintained, information must be available to management regarding what maintenance activities need to be undertaken, where within the network, when and at what frequency.

This may be achieved by setting up a maintenance management system that has the following components.

  1. Road classification by traffic volume
  2. Network  referencing
  3. Network  inventory
  4. Maintenance rating system
  5. Inspections and reporting

Maintenance Rating System

Since the recognition of a defect, determination of the cause, and the prescription of a suitable remedy are all subjective, it may be possible for different people looking at the same defect to have different solution strategies.

This can lead to poor value for money when for example maintenance is undertaken at one place whilst the need is far greater at another. This calls for a maintenance rating system so that maintenance needs will be assessed objectively.

The rating system must have standards and warning levels of deterioration.  In addition, a system for assessing the road must be developed.

The road system must be divided into categories with an inventory made of each road’s width, length, drainage, signs, markings, etc.

The information about the condition of the road is then compared with set standards in order to assess the road.

This makes it possible to summarize the scale and cost of remedial works needed to return the road to an acceptable standard for its particular category.

Inspections and Reporting

Routine inspections should be carried out on all roads according to regular schedules in order to assess current maintenance needs and update road inventory.

In general, defects categorized according to priority are reported to help management

  • to produce schedules of inspections to be carried out and their timing
  • to produce estimates of maintenance resource requirements and cost
  • to produce schedules of regularly occurring maintenance to be carried out
  • to produce programmes of work
  • to monitor the effectiveness of maintenance   activities, standards, and strategies

The frequency of inspection may range from about 24 hours for urban principal roads, main shopping areas, residential streets to about 2 times per year for rural non-principal roads.

Maintenance activities

The following are the general procedures for some important maintenance activities:

Pot-hole Patching by Pfre-mix or Hot-mixed Asphaltic Concrete

Procedures:

  1. Mark out area to be patched at least 150mm from the edge of the pot-hole and within sound and undamaged pavement with paint. Include all failed areas within a square or rectangular area with at least two sides parallel to the direction of traffic flow.
  2. Cut along the lines marked on the pavement surface so that the cut sides are vertical and the bottom of the pot-hole is level and to a depth equal to:

the depth of the existing asphalt  pavement that has been overlaid but of which the overlay has failed

or

a minimum of 100-200 mm or at least equivalent to one and a half (1½) times the depth of existing pot-hole, ensuring the excavation is in sound insitu material.

  1. Remove loose and failed material, and ensure dust is swept or blown out of the excavated hole.
  2. Compact the bottom of the pot-hole prior to placing base material to ensure soundness and flatness of the base
  3. Back-fill hole in layers with approved base material not exceeding 150mm depth of loose-fill and compact ensuring uniformity of compaction over the whole area
  4. Compact base material using suitable tampers or compaction equipment, starting around the edges and working into the centre of the pothole and ensuring that all edges and corners are compacted uniformly and in acceptable layer thickness up to the bottom of the nominated depth of pre-mix or hot-mixed asphaltic concrete to be laid
  5. Apply Emulsion at a Nominated Application Rate to all vertical faces and to the base of the pot-hole and allow to break.
  6. Wait until the emulsion breaks by turning from brown to black before adding asphaltic concrete mix.

Note:  Place the asphaltic concrete mix in holes in layers of 30mm for Pre-mix asphaltic concrete and two and a half  (2½) times the nominal size of the chippings used to manufacture the Hot-mixed asphaltic concrete

7. Compact with suitable compaction equipment, with an emphasis on all corners and edges. Always compact from the outside of the patch to the centre.

8. Repeat for each subsequent layer of asphaltic concrete mix placed until the final layer is laid loose 25mm higher than the existing pavement

9. Rake and tamp any excess mix back from the existing pavement to the edge joint of the patch making a vertical face of 45° and rake the top of the patch to a uniform level surface.

10. Firstly, compact only the outer 100mm of the patch around the whole perimeter to ensure that the joint matches the existing pavement and that correct sealing of the joints occur.

11. Continue compacting towards the centre of the patch until the whole patch is uniformly compacted without any depressions and allowing for the finished patch to be approximately 12mm above the existing pavement to accommodate for base subsidence.

12. Seal the edges of the patch with emulsion, spraying 50mm onto the old pavement and 50mm onto the new patch and seal with 5mm chippings (aggregates) to waterproof the joint

13. Clean up and remove all spoil and waste materials from the site..

Quality of Work:

  • All cutting, backfilling, and Asphaltic Concreting of pot-hole patches to be completed on the same day that the areas were worked on.
  • Ensure successive base layers are compacted around all edges and corners and that the base finishes at the nominated depth that the patch is to be filled with asphaltic concrete
  • Ensure that the finished level of the asphaltic Concrete patched pot-hole matches the line and grade of existing pavement, allowing the finished patch to be approximately 12mm above the existing pavement to accommodate for base subsidence
  • Ensure that the finished Patch has a uniform texture with good skid resistance and that the finished patch drains satisfactorily to the road shoulders.
Repair of Depressions, Ruts, Shoving and Corrugations

Procedures:

  1. Determine and mark out with paint the area to be repaired, by using a string-line or a 4-meter straight edge, laid on the pavement surface at the original grade on either side of the depression, rut, shoving or corrugation and at least 150mm from the outer limits of the failure within sound and undamaged pavement.
  2. Cut along the lines marked on the pavement surface to form a rectangle, so that the cut sides are vertical and to a depth of 300mm and finishing in sound material with the bottom of the failure flat and level. 
  3. Remove loose and failed material, and ensure dust is swept or blown out of the excavated hole.
  4. Compact the bottom of the excavated failure prior to placing base material to ensure soundness and flatness of the base
  5. Back-fill hole in layers with approved base material not exceeding 150mm depth of loose fill and compact ensuring uniformity of compaction over the whole area
  6. Compact base material using suitable tampers or compaction equipment, starting around the edges and working into the centre of the failure and ensuring that all edges and corners are compacted uniformly and in acceptable layer thickness up to:

a. Line and grade of the existing pavement if the patch is to be Bituminous Surface Dressed, allowing the finished patch to be approximately 12mm above the existing pavement to accommodate for base subsidence

Or

b. The bottom of the nominated depth of Asphaltic Concrete to be laid.

Bituminous Surface Dressing of Repaired Depression, Rut, Shoving or Corrugation

7. Apply Cut-back AC-10 Bitumen or Emulsion at a Nominated Application Rate

8. Spread Chippings (aggregates) of 14mm or 10mm as nominated in a single and uniform layer.

9. Roll or tamp chippings with suitable compaction equipment, ensuring chippings are not crushed.

Note: For Multiple Surface Treatment, apply a second coat of Cut-back AC-10 or Emulsion at the Nominated Application Rate & apply a second layer of 10mm or 7mm chipping as nominated in a single uniform layer and roll or tamp.

Pre-mixed or Hot-mixed Asphaltic Concrete of Repaired Depression, Rut, Shoving or Corrugation

10. Apply Emulsion at a Nominated Application Rate, to all vertical faces and to the base of the pot-hole and allow to break.

11. Wait until the emulsion breaks by turning from brown to black before adding Asphaltic mix.

Note:  Place the asphaltic concrete mix in holes in layers of 30mm for Pre-mix and two and a half  (2½) times the nominal size of the chippings used to manufacture the Hot-mixed asphaltic concrete

12. Compact with suitable compaction equipment, with an emphasis on all corners and edges. Always compact from the outside of the patch to the centre.

13. Repeat for each subsequent layer of asphaltic mixture placed until the final layer is laid loose 25mm higher than the existing pavement

14. Rake and tamp all the mix back from the existing pavement to the edge joint of the patch making a vertical face of 45° and rake the top of the patch to a uniform flat surface.

15. Firstly, compact only the outer 100mm of the patch around the whole perimeter to ensure that the joint matches the existing pavement and that correct sealing of the joints occur.

16. Continue compacting in towards the centre of the patch until the whole failure is uniformly compacted without any depressions.

17. Seal the edges of the patch with emulsion, spraying 50mm onto the old pavement and 50mm onto the new patch and seal with 5mm chippings to waterproof the joint.

18. Compact with suitable compaction equipment, with an emphasis on all corners and edges. Always compact from the outside of the patch to the centre.

19. Repeat for each subsequent layer of asphaltic mixture placed until the final layer is laid loose 25mm higher than the existing pavement

20. Rake and tamp all the mix back from the existing pavement to the edge joint of the patch making a vertical face of 45° and rake the top of the patch to a uniform flat surface.

21. Firstly, compact only the outer 100mm of the patch around the whole perimeter to ensure that the joint matches the existing pavement and that correct sealing of the joints occur.

22. Continue compacting in towards the centre of the patch until the whole failure is uniformly compacted without any depressions.

23. Seal the edges of the patch with emulsion, spraying 50mm onto the old pavement, and 50mm onto the new patch and seal with 5mm chippings to waterproof the joint. Clean up and remove all spoil and waste materials from the site.

Quality of Work:

  • All cutting, backfilling and Bitumen Surface Dressing or Asphaltic Concreting of failures to be completed on the same day that the areas were worked on.

Bituminous Surface Dressing of Repaired Depression, Rut or Corrugation

  • Ensure finished base work of the patched pot-hole matches the line and grade of existing pavement and allow the finished patch to be approximately 12mm above the existing pavement to accommodate for base subsidence
  • Ensure that the finished Patch has a matt texture with good skid resistance
  • Ensure work site is left in a clean and safe condition with no loose aggregate on pavement surface and adhering to environmental requirements
  • Ensure the finished patch drains satisfactorily to the road shoulders

Pre-mixed or Hot-mixed Asphaltic Concrete Repaired Depression, Rut Shoving or Corrugation

  • Ensure successive base layers are compacted around all edges and corners and that the base finishes at the nominated depth that the patch is to be filled with asphaltic concrete
  • Ensure the finished level of the Asphaltic Concrete patched pot-hole matches the line and grade of existing pavement and allow the finished patch to be approximately 12mm above the existing pavement to accommodate for base subsidence
  • Ensure that the finished Patch has a uniform texture with good skid resistance and that the finished patch drains satisfactorily to the road shoulders
  • Ensure work site is left in a clean and safe condition with no waste asphaltic concrete mix on the pavement surface, and adhering to environmental requirements
  • Monitor road for reoccurring depressions, ruts, shoving and corrugation and report on their performance on a regular basis
Maintenance of roads

Procedures:

1. Determine and mark out with paint the area to be repaired, by using a string-line or a 4-meter straight edge, laid on the pavement surface parallel to the defined road edge and 300mm from the outer limits of the failure within sound and undamaged pavement.

2. Cut along the lines marked on the pavement surface to form a rectangle, so that the cut sides are vertical and to a depth of 300mm and finishing in sound material with the bottom of the failure flat and level. 

3. Remove loose and failed material, and ensure dust is swept or blown out of the excavated hole.

4. Compact the bottom of the excavated failure prior to placing base material to ensure soundness and flatness of the base

5. Back-fill hole in layers with approved base material not exceeding 150mm depth of loose-fill and compact ensuring uniformity of compaction over the whole area

6. Compact base material using suitable tampers or compaction equipment, starting around the edges and working into the centre of the failure and ensuring that all edges and corners are compacted uniformly and in acceptable layer thickness up to:

1. Line and level of the existing pavement if the patch is to be Bituminous Surface Dressed, allow the finished patch to be approximately 12mm above the existing pavement to accommodate for base subsidence

Or

2. To the bottom of the nominated depth of Asphaltic Concrete to be laid

Bituminous Surface Dressing of Edge Failure

7. Apply Cut-back AC-10 Bitumen or Emulsion at a Nominated Application Rate

8. Spread Chippings (aggregates) of 14mm or 10mm as nominated in a single and uniform layer.

9. Roll or tamp chippings with suitable compaction equipment, ensuring chippings are not crushed.

Note: For Multiple Surface Treatment, apply a second coat of Cut-back AC-10 or Emulsion at a the Nominated Application Rate & apply a second layer of 10mm or 7mm chipping as nominated in a single uniform layer and roll or tamp.

Pre-mixed or Hot-mixed Asphaltic Concrete  of Edge Failure

10. Apply Emulsion at a Nominated Application Rate, to all vertical faces and to the base of the compacted pot-hole and allow to break.

Wait until the emulsion breaks by turning from brown to black before adding Asphaltic mix.

Quality of Work:

  • All cutting, backfilling and Bitumen Surface Dressing or Asphaltic Concreting  of failures to be completed on the same day that the areas were worked on.

Bituminous Surface Dressing of Repaired Edge Failure

  • Ensure finished base work of the patched edge failure matches the line and grade of existing pavement
  • Ensure that the finished Patch has a matt texture with good skid resistance
  • Ensure work site is left in a clean and safe condition with no loose aggregate on pavement surface and adhering to environmental requirements
  • Ensure the finished patch drains satisfactorily to the road shoulders

Pre-mixed or Hot-mixed Asphaltic Concrete  Repaired Edge Failure

  • Ensure successive base layers are compacted around all edges and corners and that the base finishes at the nominated depth that the patch is to be filled with asphaltic concrete
  • Ensure the finished level of the Asphaltic Concrete patched edge failure matches the line, level and grade of existing pavement with a safe rounded shoulder drop-off edge.
  • Ensure that the finished Patch has a uniform texture with good skid resistance and that the finished patch drains satisfactorily to the road shoulders
  • Ensure work site is left in a clean and safe condition with no loose aggregate on pavement surface and adhering to environmental requirements
  • Monitor edge failure repairs and report on their performance on a regular basis
Resealing and sealing

Procedures:

1. Mark out the extent of road to be Resealed or Sealed by clearly painting a line across the full width of the road pavement at the start and finish of the area to be sealed.

2. First: Repair Pot-holes and Edge Failures by the appropriate procedures

3. Sweep the full extent of the area to be sealed by Tractor Broom or Hand Broom to ensure all dust and deposited dirt is removed from the road surface. Ensure that the operator or sweepers take account of the wind direction to ensure that dust is not blown back onto the swept surface

4. Mark with paint the start and finish of the initial bitumen sprayer run (i.e. Length) which will be dependent on the amount of chippings in spreading trucks on site at the time of spraying.

5. Mark with paint, string-line or small stones the edge line for the sprayer driver to follow.

6. Paper the transverse joints at the start and finish of each run.

7. Set up the Bitumen Sprayer 20 meters back from the start of the run and ensure that the spray bar is set to its correct width and that the driver’s guide bar is properly set and a Dip of the Volume of Bitumen is measured and recorded along with the sprayer temperature.

8. Immediately behind the Bitumen Sprayer set-up the Chip Spreading Vehicles, followed immediately by the Pneumatic-Tyred Rollers.

9. The Supervisor instructs the Sprayer Driver what the Hot Bitumen application rate is and reads the correct road speed off the chart so as to set the vehicle speed.

10. The Bitumen Distributor sprays the required rate of Bitumen uniformly over the whole extent of the work, without stopping until it has reached the designated finishing point and then the driver/operator dips the distributor on flat ground so as to record the actual bitumen usage.

11. The Mechanical Chip Spreading equipment follows closely behind the Bitumen Distributor spreading a uniform single layer of chippings and leaving a 150mm wet edge if needed for the adjoining bitumen run, ensuring that complete coverage is achieved and that all chippings required are distributed in the work zone.

12. Embed the chippings with the Pneumatic-Tyred Roller by following close behind and at a speed of between 10-15km/hr to ensure that the whole mat is uniformly rolled in straight runs. Rollers will continue rolling until instructed to stop and must ensure minimum rolling time is observed.

13. Sweep any excess pile of chippings off the road and add chippings by hand as necessary.

Note:  If a second coat seal is required immediately after laying the first coat repeat the same process, ensuring that any excess loose chippings from the first coat is removed prior to the second coat.

Note:  Offset Transverse joints on the second coat so as not to overlay the same position of first coat.

14. Open road to slow moving traffic and control vehicle speed to minimise whip-off  of chippings.

15. Clean up and remove waste materials and excess from shoulders, drains and site

Quality of Work:

  • The finished seal surface shall have a uniform Matt Texture with a single layer of nominated chippings and a minimal amount of loose chippings (aggregate) on the surface.
  • Ensure no transverse or longitudinal joints are raised or bleeding.
  • Ensure the Daily Spray Record Sheet is correctly filled out immediately after completing each sprayer run, and that the bitumen and chipping spread rates meet the Targeted Design Rate criteria.
  • Ensure that all loose chippings are removed from the site and road.
  • Ensure that adequate signage is in place to warn the public of the need to take care of the new work in its early set-up stages.
  • Monitor sealed areas and report on their performance on a regular basis
Crack Sealing

Procedures:

1. Initiate proper traffic control safety procedures at job site

2. Mark all areas prior to cleaning site to define the extent of work

3. Sweep clean or blow out cracks with compressed air over the area showing cracking ensuring that the area is completely dry

Transverse and Longitudinal Cracking:

 Note: Cracks greater than 6mm should be cleaned out to a depth of equal to or greater than 10mm , preferably by use of a routing cutting machine.

4. Heat cut-back bitumen or emulsion to the specified temperature and spray by bitumen hand lance or pour by watering can the bitumen product into the cracks by following the crack pattern. The nozzle of the dispenser must be held as close as possible to the road surface and keep the width of spread to as small as possible.

5. Spread 5mm chippings (aggregate) over the strip of binder by using a suitable hand tool dispenser.

6. Lightly tamp the chippings into the binder

Alligator Cracking:

7. Define all areas to be sealed with paint in squares or rectangle

8. Produce a slurry by mixing emulsion with 5mm chippings (aggregate) in the ratio of  6 litres of emulsion with 20 kilograms of 5mm chippings, in a mixer or a barrow.

9. Spread the slurry over the area to be cracked sealed and use flat edged rakes or mops to spread in a thin layer of approximately 5mm thickness over the whole marked area

10. Allow the area to dry completely before allowing traffic to pass over the repair.

11. Clean up and remove waste materials and excess aggregate from site

Quality of Work:

  • Ensure all crack sealing is flush with the existing pavement and sealed onto the existing pavement.
  • Ensure that the cracks are sealed with 5mm chippings to prevent pick up by vehicle wheels.
  • Monitor crack repairs and report on their performance on a regular basis
Resurfacing of Asphaltic Concrete Road with an overlay

Procedures:

1. Mark out the extent of road to be overlaid with asphaltic concrete by clearly painting a line across the full width of the road pavement at the start and finish of the area to be overlaid.

2. First: Repair Pot-holes and Edge Failures, Depressions, Ruts, Shoving and Corrugation and Cracks

3. Sweep the full extent of the area to be overlaid by Tractor Broom or Hand Broom to ensure all dust and deposited dirt is removed from the road surface. Ensure that the operator or sweepers take account of the wind direction to ensure that dust is not blown onto the swept surface

4. Mark with paint and a string-line the edge line for the paver driver to follow and the beginning and end of the paver run.

5. Set up the Bitumen sprayer or small hand spraying unit loaded with Emulsion at the start of the run and commence lightly Tack Coating the area to be overlayed with emulsion at the specified application rate

6. Align the Asphalt Paver at the commencement of the overlay run and set the screed to the correct width and to the loose laying depth ( ie 12% higher than the compacted finished level)

7. Heat the screed board by use of the paver burners and back the first truck load of Asphalt into the paver hopper

8. Test the temperature of the mix deposited into the hopper to ensure it is at the correct temperature to lay

9. Drive paver forward, laying a uniform mat with minor corrections of the paving levels being adjusted  by the screed operator as necessary

10. The paver operator drives at an optimum speed to ensure that the paver and trucks supplying mix are continuously moving

Note: The paver should never stop or start on the job, to pick up mix as this will result in depressions and humps in the new pavement – (ensure that minimal forward progress by the paver is maintained while filling paver hopper or waiting for the next load of mix)

11. The Raker tries to minimize damage to the new mat and only add mix or remove mix on low or high points as necessary

12. With a steel drum vibratory roller, commence initial break rolling to the nominated rolling pattern designated by the supervisor, ensuring that the vibratory unit is operating correctly and that the watering units on the drums are preventing pick up

13. Follow the initial break rolling by the steel vibratory drum roller, with a pneumatic tyre roller to knead the mat, until a uniform texture is achieved throughout.

14. Finally, re-roll with the steel drum roller to eliminate any marks left by the pneumatic tyre roller, as the final pass

Note: The rolling of the mat should take place as close to the paver as possible and while the pavement still retains its heat

Note:  Care must be taken in the rolling pattern to ensure the mat is not shoved, torn or over compacted thereby requiring a skilled operator to undertake the initial rolling passes

Note: If Longitudinal joints or Transverse joints are within the work scope these must be rolled first by crimping a 100mm overlap of the joint with the existing pavement to ensure proper joint closure and line and level.

15. Open road to slow-moving traffic and control vehicle speed in the initial stages of usage, ensuring that vehicles do not get stopped for extended periods on the new mat when freshly laid.

16. Clean up and remove waste materials and excess from shoulders, drains and site

Quality of Work:

  • The finished asphaltic concrete mat shall have a smooth homogenous texture
  • Areas of poor texture, rideability or any obvious flaw shall be removed for the full width of the run and to a length nominated by the Supervisor and repaved
  • Cores shall be taken as per the Testing specification and tested to ensure conformance of properties
  • Ensure that adequate signage is in place to warn the public of the need to take care of the new work in its early set-up stages.
  • Monitor asphaltic concrete overlay and report on their performance on a regular basis
Re-gravelling of Gravel Roads

Procedures:

1. Mark out the extent of road to be graded.

2. Scarify the existing surface by ripping to a minimum depth of 50mm below the average maximum depth of the overall pavement deformations, thereby loosening the material for reshaping of the pavement

Grading Option 1: The Grader starts from the Centre-line and works to the edge

3. Commencing on one side of the road at the center-line and in passes no longer than 200 metres, the grader operator will commence to turn all the scarified material into a wind-row of material, towards the outer edge of the road formation.

4. The grader turns around and returns on the opposite side of the center-line again turning materials to the outer edge of the road.

5. Continue the looping pattern of grading until all material is wind-rowed on the outer edge of the road formation. (this may take 2 or 3 passes to trim material to a solid sub-base)

Grading Option 2: The Grader starts from the Outer edge of the road formation and works to the center-line and then onwards to the opposite outer edge of the Road formation

6. Commencing on one side of the road at the outer edge and in passes no longer than 200 metres, the grader operator will commence to  turn all the scarified material into a wind-row of material, towards the opposite outer edge of the road formation.

7. The grader either backs up or turns around after each pass and continues turning materials to the opposite outer edge of the road.

8. Continue the pattern of grading until all material is wind-rowed on the outer edge of the road formation. (this may take 2 or 3 passes to trim material to a solid sub-base)

Compaction requirements and new sub-base placement:

9. Compaction equipment is then used to proof roll the undisturbed sub-base from outside of the road to the centerline, so as to ensure maximum density and uniformity of line and level by the rollers looping around the work site from outside to the center-line

10. Ensure that a clearly defined Crown in the formation is aligned up the center of the road

11. Turn windrowed material back into excavated areas in layers not deeper than 150mm and add water to the loosely packed gravel.

12. Remove all materials greater than 100mm by hand from the surface prior to compaction

13. Start compacting the layer of loose material from the outside of the road into the centerline

14. The grader operator will repeat the process of spreading the old gravel and having the layers compacted, up to the new gravel replacement level.

15. New sub-base material will be dumped at measured intervals along the job site as calculated by the Supervisor/Contractor dependent on the nominated compacted fill depth.

16. The grader operator will spread the new gravel up to the finished surface level ensuring that the correct camber, cross-fall and alignment are at the required depth and that all excess material is graded beyond the pavement and not impeding water shed

17. Completing one half of the road at a time up to the crown level and alignment.

18. Compact the finished layer to a hard dense uniform surface.

19. Cross-falls shall be checked by use of a camber board at intervals no greater than 25meters.

20. Repeat the process on the opposite side of the gravel road ensuring the shape and profile of cross-section of the road are maintained.

21. Clean up and remove waste materials and excess from shoulders, drains and site

Caution: 

  • The grader should not make a final pass down the center line of the road with a horizontal blade as this destroys the crown and will cause flattening and ponding in the center of the road
  • Turnouts have to be cut to ensure that water is led away from the edge of the road by following the natural contour.
  • No stockpiles of material should be left on the road overnight without adequate barriers and signage designating the area

Quality of Work:

  • All planned work shall be completed and closed in one day to ensure the road is open to traffic overnight without creating a hazard to the traffic.
  • The finished pavement shall be dense and hard of uniform texture with correct alignment, cross-fall and camber
  • All excess material has to be removed from the pavement and edges ensuring a clean work site with good drainage
  • Ensure that adequate signage is in place to warn the public of the need to take care on the new work in its early set-up stages.
  • Monitor re-gravelled road and report on its performance on a regular basis
Ditch cleaning

Procedures:

1. Mark out area to be cleaned by designating with flags or marker poles the extent of the length of ditches to be cleaned by manual means.

Unlined Drain:   

2. Cut and remove all large trees and shrub that has commenced growing within drain.

3. Trim all grass within drain to a height of less than 50mm leaving a short grass cover throughout the extent of the ditch

4. Remove any silt build up or rubble and rubbish that have been deposited in the invert of the ditch to eliminate all possibility of ponding.

5. Check the invert of the ditch to ensure sufficient fall to remove water and dig out depth of ditch as needed to facilitate water flow

6. Clear and widen outfall or add turn-outs as needed to ensure that water flows away without creating a scour at the end.

7. Where digging is needed ensure the side walls of the ditch have a slope between 1:1 and 2:1 thereby minimizing the possibility of scouring and erosion of invert and side walls

Lined Drain:

8. Dig out and remove all silt and rubbish build up throughout the length of the ditch

9. Pull out, chip or poison any weeds and plants growing through the lining of the drain

10. Clear and widen outfall to ensure the water flows away without creating a scour at the end.

11. Clean up and remove waste materials and rubbish from site.

Quality of Work:

  • Ensure ditches are clear of all deleterious material and that water flows freely with a minimum of scouring or erosion action at the end of the day.
  • Ensure the slopes of ditches are stable and not susceptible to erosion and slumping.
  • Ensure that cut-off and turnout drains are adequately spaced and properly cleared to minimize silt build-up and to ensure that water escapes on a broad flow
  • Ensure work site is left in a clean and safe condition with all rubble and rubbish removed

Preparation of premix for pavement patching

Premix is a mixture of graded aggregate and cutback asphalt used for patching paved roads. The cold mixture is prepared in the following manner:

1. Cutback formulation
The cutback asphalt is prepared by mixing kerosene with 80/100 pen grade asphalt. The asphalt is heated to a temperature of 80-90oC before the required quantity of cutter (kerosene) is added. A quantity of 36 litres (8 gallons)of kerosene is required for mixing with one drum or 153 litres of  the asphalt in order to obtain approximately an 80 percent cutback. The kerosene is added in increments of 5 litres at a time and thoroughly stirred to ensure good mixing before the next increment.

2. Gradation of aggregates
The gradation of the aggregates to be used in the premix is as follows

Sieve Size% Passing
25mm100
20mm90-100
12.540-80
No. 435-65
No. 50 5-20
No. 2000=5

3. Quantity of cutback

About 5.5% cutback by weight of aggregates is required to obtain a workable and durable pre-mix. In the case where the proportion of fine material in the mix is on the high side, the quantity of cutback to use for the premix may be adjusted upwards to 6%.

4. Mixing and curing

The aggregate in a dry condition (heated slightly if needed) is mixed with the required quantity of cutback which has been heated to a temperature of 80-90oC and thoroughly mixed until all particles become uniformly coated with binder. 

The mix is stockpiled and covered with tarpaulin to avoid contact with rain for a period of 3-10 days for it cure and become sufficiently stable for use.

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