BRIEF NOTE ON FILLING OF POT HOLES & PATCH REPAIRS

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3 BRIEF NOTE ON FILLING OF POT HOLES & PATCH REPAIRS 1

4 DEFINITION: POT HOLES ARE IRREGULAR SHAPED HOLES OF VARYING SIZES IN A SURFACE LAYER OR EXTENDING TO THE BASE COURSE CAUSED BY LOCALISED DISINTEGRATION OF PAVEMENT MATERIAL. TYPES : SHALLOW POTHOLES DEEP POTHOLES 2

5 SHALLOW POT HOLES : It is a Pothole extending within the Bituminous surface but not reaching base course/ sub-base base course which are intact. 3

6 DEEP POT HOLES It is a Pothole extending through the bituminous layers down to base course or sub- base course or even upto subgrade level. 4

7 CAUSES FOR POTHOLE FORMATION 1. Ingress of water into the pavement through surface course due to alligator cracks 2. Lack of camber resulting in ponding 3. Rutting along wheel-path 4. High berms / shovelling of materials 5. Lack of shoulder drains. 6. Depression in the pavement leading to stagnation of water. 7. Hungry road surface (e.g. ravelling, exposed texture) 5

8 Contd. 8. Poor quality of materials used for the construction of the pavement (for e.g. excess/ lack of fines in dense graded mixtures, soiled aggregates, excess/shortfall of binder content) 9. Bad construction practices resulting in early onset of cracks/ depression in the pavement, for e.g. a. Insufficient compaction b. Excess of blindage in WBM layers (with highly plastic material) c. Uneven distribution of binder d. Inadequate camber e. Inadequate Primer/ Tack-coat coat f. Manual spraying in lieu of mechanical spraying for primer/ tack coats g. Not maintaining correct mix temperatures at the time of laying and compaction 6

9 Contd Lack of lateral support to the pavement layers 11. Poor premix quality or workmanship 12. Faulty operation of the spraying equipment while applying : - Bitumen binder for the surface dressing leads to streaks of insufficient binder. - Tack coat & coating to aggregates leads to streaks of insufficient binder. 7

10 FILLING OF POTHOLES & PATCH REPAIR 1. Scope 2. Materials 3. Preparation of the area for pot- hole and patch repair 4. Backfilling operation. 8

11 1. SCOPE : 1. Removal of all failed material in the pavement courses and, if necessary, below the pavement, until the root cause of the failure is removed. 2.Cutting/ trimming of the pothole to geometrical shape. 3. Replace with similar material adjacent to it as far as possible. 9

12 4. The painting of tack coat on to the sides and bases of excavations prior to placing of any bituminous materials. 5. The compaction, trimming and finishing of the surfaces of all patches to form a smooth continuous surface, level with the surrounding road. 10

13 2. Materials: 1. Materials used for the pot-hole and patch repair of bituminous surface and underlying layers shall be in accordance with the specifications and shall be of the same type as specified for the original construction. 2. A mix superior to the one on the existing surface may also be used for repair work. 3. Non-bituminous material shall not be used for patching bituminous layers. 4. The grading of aggregates and bitumen content of the mix used for, shall be in accordance with specification requirement. 11

14 3. Preparation of the area for pot- hole and patch repair : 1. Each pot-hole and patch repair area shall be inspected and all loose material removed. 2. The area shall be cut/trimmed either with jack hammers or with hand tools suitable for the purpose, such that the defective material responsible for the failure is all removed and such that the excavation is of a regular shape. 3. The edges of the excavation shall be cut vertically. 4. The area shall be thoroughly cleaned with compressed air or any appropriate method approved by the Engineer to remove all dust and loose particles. 12

15 5. Layers below the level of the bituminous construction shall be replaced using material of the equivalent specification to the original construction, which shall particularly include the specified standards of compaction. 6.The area for bituminous construction shall be tacked or primed with cutback or emulsion depending upon whether the lower area is bituminous or granular in nature. 7. The sides, however, are to be painted with hot tack coat material. 8. The prime coat and tack coat shall conform to Clauses 502 and 503 of these Specifications, respectively. 13

16 4. Backfilling operation (Mix Material, wearing coat / Seal coat) 1. The mixture to be used in bituminous patching shall be either a hot mix or a cold mix. 2. Mixing shall be done in a plant of suitable capacity. 3. The bituminous mixture shall be placed in layers of thickness not more than 100 mm (loose) and shall be compacted in layers with roller/plate compactor/hand rammer to the compaction standards. 14

17 4. While placing the final layer, the mix shall be spread slightly above the surface so that after rolling, the surface shall be flush with the adjoining surface. 5. If the area is large, the spreading and leveling shall be done using hand shovels and wooden straight edges. 6. During the process of compaction the surface levels shall be checked using a 2 m or 3 m straight edge. 15

18 Resources Work Force 1 Work Inspector 1 skilled labour to apply 1 spray bitumen 2 to 4 workmen 2 traffic controllers Plant and Tools Tipper / Flat bed truck or tractor trailer This for transporting Personnel Equipment Aggregate Binder in drains (Bitumen/Emulsion) Premixed materials (if used) A small vibrating roller or A small vibrating plate compacter or Hand rammers (2 No s) 16

19 Small items of equipments 2 Wheelbarrows 4 Showles 4 Pick Axes 2 Hand rammers 4 Brooms 2 Watering cans 2 Rubber sponges Bitumen thermometer If bitumen emulsion is used 1 cold emulsion single drum mechanical sprayer If bitumen is used 1 boiler to heat bitumen and mechanical sprayer 2 metre straight edge Chalk for marking 17

20 Materials Coarse Aggregate / Mix material Gr II or Gr III WBM Aggregates or WMM mix material 40 mm & down size Aggregates 20 mm & down size Aggregates 10 mm & down size Aggregates 6 mm & down size Aggregates Fine Aggregate 2.36 mm & down size Aggregates Bitumen Binder Cold bitumen emulsion or Cut back bitumen or 80/100 penetration grade bitumen Bituminous mixes (premixed) Bituminous Macadum (BM) SDBC or MSS or BC (wearing coat) 18

21 SIGNS AND SAFETY EQUIPMENT Advance warning signs 2 men working signs 2 end of restriction signs Site protection equipment 4-10 traffic cones 2 reversible stop/go signs Safety equipment Yellow / Orange shoulder belts for Gangmen Red and white striped marker boards for patching vehicles 19

22 RESOURCE AVAILABILITY Before the work starts it is necessary to ensure That all necessary personnel are available That all items of equipment to be used are available and in good condition That all small items of equipment, hand tools and the necessary traffic signs are available That all required type and quantity of binder, as specified on the work sheet is available That the aggregate is available at the storage sites specified on the worksheet 20

23 ABSTRACT MATERIALS COMPONENT REQUIREMENT - MAJOR DISTRICT ROAD (MDR) Sl No Nature of Work Bitumen (80/100 grade) Emulsion Aggregate (loose quantity) WBM/WMM BUSG MSS Maintenance estimate of major district road 2 % area pot holes / patch repair (with out edge correction) 2 Maintenance estimate of major district road 3 % area pot holes / patch repair (with edge correction) 149 kgs (0.95 barrel) 335 kgs (2.15 barrel) 22.5 kgs 1.35 cum cum 22.5 kgs 1.35 cum 4.25 cum 3.04 cum 21

24 ABSTRACT MATERIALS COMPONENT REQUIREMENT - STATE HIGHWAYS (SH) Sl No Nature of Work Bitumen (80/100 grade) Emulsion Aggregate (loose quantity) WBM/WMM BUSG MSS Maintenance estimate of State Highways. 2 % area pot holes / patch repair (with out edge correction) 2 Maintenance estimate of State Highways % area pot holes / patch repair (with out edge correction) 228 kgs (1.46 barrel) 521 kgs (3.34 barrel) 33 kgs 7.50 cum cum 33 kgs 7.50 cum 6.22 cum 4.46 cum 22

25 Post Monsoon Maintenance of Roads SH & MDR Potholes/patch repair works (Items to be operated) a) For Shallow potholes Open graded premix surfacing (OGPS) or Mix Seal Surfacing (MSS) b) For Deep Potholes Wet Mix Macadam or Water Bound Macadam Primer coat Mix Seal Surfacing c) For Edge Correction Tack coat Built up Spray Grout Mix Seal Surfacing 23

26 Good Construction Practices Steps involved for new pavement 1. Clearing and grubbing of original ground 2. Compaction of original ground 3. Drainage work 4. Cross Drainage Works 5. Sub-grade layer 6. Granular Sub-base layer 7. WBM 8. Surface Dressing 9. Bituminous Macadam 10. Mix Seal Surfacing 11. Shoulders 12. Caution/Sign/Information Boards 13. Kilometer / Hectometer Stones It leads to better serviceability in terms of good riding quality for the road user 24

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28 POT HOLES FORMED DUE TO INADEQUATE MAINTENANCE 26

29 POT HOLES FORMED DUE TO INADEQUATE MAINTENANCE 27

30 UNSCIENTIFIC WAY OF DOING PATCHING OF POT HOLES 28

31 ROAD WITH BROKEN EDGES ROAD WITH POTHOLES 29

32 PATCHING OF POT HOLES BEING DONE WITH OUT PROPER CLEANING POT HOLE FILLING NOT DONE PROPERLY 30

33 DEFECT: EDGE SUBSIDENCE AND RUTTING Location : Usually 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 and restoration of shoulder (see Volume I), - deep subsidence: local restoration of the pavement structure 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. 31

34 DEFECT: EDGE DAMAGE (degradation of pavement structure) Location Along the edges of the pavement*. 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 rainy season. Remedies - local restoration of the pavement structure 32

35 DEFECT: POTHOLES (degradation of the pavement structure) Location No 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 33

36 RESOURCES 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. 34

37 PLANT AND TOOLS Patching Vehicle* Specially equipped vehicle or towed equipment fitted with a heated tank for the binder and a double hopper for the aggregates. OR If, not available, a suitable means of heating (unless bitumen emulsion is used) and applying the bitumen are required. e.g. towed bitumen heater/distributor. Tipper/Flat Bed Truck, or Tractor and Trailer For transporting the aggregates, small items of equipment and the personnel. 35

38 MATERIALS The materials used consist of aggregates*, and bituminous 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 grading requirements set by the engineer. The maximum size of aggregate varies according to the type of work involved, normally: - sanding...dmax = 5 mm - surfacing...dmax =10 mm - base course...dmax =20mm/40 mm (Dmax = nominal maximum diameter) In addition to the grading it is also necessary to check the hardness and the cleanliness of these aggregates. These properties should be tested regularly 36 according to the specifications.

39 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 surface as a film or used in bituminous mixtures. Bitumen film The 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 consist of: - bitumen emulsion slurries - applied immediately after manufacture, - cold bitumen emulsion mixtures - manufactured in advance of their application, - hot fluxed or cut back bitumen mixtures (hot mix) applied immediately after manufacture. 37

40 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: traffic cones, - 2 reversible "Stop/Go" signs. Safety Equipment Use 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. 38

41 FILLING IN DEPRESSIONS This treatment is applied to deal with subsidence and surface irregularities due to shoving 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. The surface 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) 39

42 4 Application of a tack coat (d) Hot cut back bitumen is applied with a spray lance 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 during heating. 5 Fill in the depression (e) The cold mix is placed within the marked outline using 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 the small vibrating roller, plate or a rammer, until the level is 3 mm proud of the surrounding surface. 7 Resealing The repair must be sealed to prevent penetration of water 40

43 SURFACING PATCHING This treatment is used to repair local aggregate loss and is carried out in the following steps: 1 Sweep the area The area must be swept out by hand. The surface must be clean and dry. 2 Mark out the area to be repaired The surfacing that is to be repaired is outlined in chalk. OPTION 1: SEAL Use cold emulsion or hot cut back bitumen to seal the area to be repaired and provide a tack coat at the following rates: 1.5 kg/m 2 for bitumen emulsion 1.0 kg/m 2 for cut back bitumen. Apply the chippings (such as 6-10 mm size) and ensure a complete coverage. Lightly roll the chippings into the bitumen using a roller or vehicle tyres. 41

44 OPTION 2: PREMIX A hot cut back bitumen is applied to the area of the repair 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. 42

45 BASE PATCHING This is the treatment that is used to repair: - mesh cracking - ruts and depressions - edge subsidence and rutting - edge surface failure - Potholes - shoving Four steps are involved: 1 Marking out the area to be repaired The area to be treated is marked out with chalk by drawing a rectangle around the defects. 43

46 2. Excavation of the area to be repaired It is necessary to: remove all material from within the marked out area of the road surface, increase the depth of the hole until firm, dry material 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 is flat, horizontal and free from loose material then compact it. 44

47 3. Backfilling the hole The hole is filled with a selected well graded material 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 in one 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 to allow for settlement on compaction. Compaction is continued depending on the size of the excavation, using the vibrating roller, plate compactor or with a rammer, until the surface is level. 4 Resealing The repair must be sealed to prevent penetration of water 45

48 COMPLETION AND REMOVAL OF TEMPORARY SIGNS 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 the repairs, sand all areas where too much binder has been 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. 46

49 On completion of the repairs and finishing the work, 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 following order: - the traffic cones (a), - the two "End of Restriction" signs, - the two "Men Working" signs (b). NOTE: SHOWN FOR DRIVING ON THE RIGHT 47

50 ALLIGATOR CRACKING 48

51 LONGITUDINAL CRACKS EDGE CRACKS 49

52 BLOCK CRACKING 50

53 SETTLEMENT AND UPHEAVAL STRIPPING 51

54 EDGE FAILURE 52