Yesterday, BBMP Special Commissioner Randeep Dev said on Twitter, that all engineers have been instructed to strictly comply with the methodology for filling potholes. BBMP had specified the nine-step methodology for filling potholes last December, following High Court’s orders in PIL No 42927/2015.
Dev said that BBMP is also insisting on geo-tagged photos of potholes before and after patching, to ensure transparency and accountability.
According to Dev, following is the methodology for pothole patching/repair that BBMP engineers have to adhere to.
Step 1: Place traffic control devices
Place traffic cones, flags, flagman to guide and control the traffic movement
Step 2: Marking the defective/pothole area
Sweep away the loose materials of the pothole
Mark the area using chalk to rectangular/square shape
Ensure straight sides and square corners while marking
Step 3: Cutting out defective area
Using Mechanical Cutters
Cutting to be carried out from the centre to sides/edges
Cut down up to stable layer below
Vertical sides are to be ensured during cutting
Step 4: Removal of loose materials
Remove all loose material from the pothole area
Blow out the fine material from the potholes using compressed air
Do not leave any loose material in the pothole or on the pavement surface
Cleaning should be done by using air compressor only
It was instructed to rectify uneven manholes, if any. The Field engineer should see that milling should be done before taking up any asphalting work, so that the existing manhole cover shall match with the road level
Manual cleaning is prohibited
Step 5: Apply Prime coat and tack coat Prime coat
Apply prime coat, if the bottom layer of the pothole is of Wet Mix Macadam
Apply prime coat using Slow Setting – 1 Emulsion (SS1)
Quantity of emulsion to be sprayed is 0.7 to 1.0 kg/sqm
Use sprayers
Do not pour the emulsion into the pothole
Ensure uniform spray of emulsion on sides and bottom surface of pothole
Do not put extra water into emulsion
Tack coat
Apply Tack coat, if the bottom surface is Wet Mix Macadam coated already with prime coat or bituminous surface
Ensure that the application of tack coat on the sides of the cutting edge is also achieved
Apply tack coat using rapid setting emulsion (RS 1)
Quantity of Tack coat
| Type of surface | Rate of spray / Quantity of emulsion, kg/sqm |
| Bituminous surface | 0.20 to 0.30 |
| WMM surface treated with prime coat | 0.25 to 0.30 kg/sqm |
Step 6: Placing of bituminous mix in the pothole
Use squared pointed showed for placing the bituminous mix
Put mix in corners and sides first and then proceed to centre portion
If the pothole is deep, put the mix in layers not exceeding maximum of 75 mm thickness
Place additional layer after compacting the first layer
Step 7: Compaction
Size of roller drum should be smaller than the pothole size
Use vibratory tandem roller only if the pothole size accommodates the roller drum width
Use walk-behind-rollers/plate vibrators for compaction
Compaction to start from corner and edges, and then proceed to central portion
First two passes of the compactor to be static passes, and then remaining passes with vibrations
Check the surface profile using straight edge
Ensure uniform even surface after compaction
Minimum temperature during compaction of hot bituminous mix should not be less than 90 °C
Step 8: Cleaning of pothole patched site
Clean the patch site properly
Dispose the materials at the designated place
Ensure no loose bituminous material near pothole-patched site/pavement