05 rehabilitation works

8/13/2019 05 Rehabilitation Works

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5 ROAD REHABILITATION WORKS

5.1 Introduction

5.2 Using Labour Only

5.3 Using Labour Plus Intermediate Equipment

5.4 Using Mainly Equipment

5.5 Spot Improvement

5.6 Small Structure Works

5.7 Reconstruction of Gravel Shoulders on BitumenRoads

5.8 Quality Control

5 2

5 3

5 13

5 23

5 33

5 41

5 41

5 - 44

5R

OADREHABI

LITATIONWO

RKS


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Improvement Works 5 ROAD REHABILITATION WORKS

5 - 2

5 ROAD REHABILITATION WORKS

5.1 INTRODUCTION

Under Roads 2000 strategy the existing classified road network needs to be first partially

rehabilitated before maintenance can be effectively established. Spot improvement activities

are carried out after the initial rehabilitation works have been carried out. Depending on

certain circumstances, there are three rehabilitation methods that can be applied:

Using Labour Only:

This approach is appropriate for roads with a low traffic level and where sufficient local

labour is available.

The first labour gang establishes the centre line, sets out the road formation and reserve

width, and clears the road reserve area of bush and grass.

The second labour gang excavates the side drains and forms the camber. Compaction

may be achieved by traffic or pedestrian rollers.

The third labour gang opens mitre drains, cross water drains and places/replaces culvert

lines.

See details of this method in Section 5.2 (pages 5-3 to 5-12)

Using Equipment and Labour:

This approach is appropriate for roads with a higher traffic level and where sufficient local

labour is available.

The first labour gang establishes the centre line, sets out the road formation and reserve

width, and clears the road reserve area of bush and grass.

The second gang consists of motor or towed grader(s) and forms the camber. The grader

DOES NOT cut drains. Compaction is achieved using towed or self-propelled rollers.

The third labour gang opens all drains, cross water drains and places/replaces culvert

lines.


Using Mainly Equipment:

This approach is appropriate for roads where there is insufficient labour available, e.g.

semi arid and arid areas.

The first working gang establishes the centre line, sets out the road formation and reserve

width, and clears the road reserve area of bush and grass. Most of the clearing work is

done using equipment, such as dozer and grader, and supported by labour for minor

works.

The second gang consists of motor or towed grader(s) to excavate/clean the side and

mitre drains and to form the camber.

The last gang, mainly labour, deals with other drainage works. This includes scour-check

installation, cleaning of culverts and repair or installation of new culverts.



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5 - 3

5.2 USING LABOUR ONLY

In order to achieve satisfactory workmanship and simplify supervision, the road rehabilitation

process is broken down into a series of simple activities. They are carried out by separate

groups of labourers, in a sequence. In this way a train of activities moves along the roadimproving the carriageway and drainage in a controlled step-by-step manner.

The work is subdivided into three main operations, each carried out by a separate labour

gang that follow each other in sequence:

SETTING OUT + CLEARING

1st labour gang

CAMBER FORMATION

2nd Labour Gang

DRAINAGE WORK

3rd labour gang

Gang 1angGang 2ang 2Gang 3ang 3

The activities necessary for the labour only partial rehabilitation approach should be selected

from the following schedule and carried out in the sequence shown:

SEQUENCE OF PARTIAL REHABILITATION ACTIVITIES FOR EARTH AND GRAVEL ROADS

USING LABOUR ONLY

Operation Activity For Details Refer to:

Site Support Work Site Camp Installation

Site Camp Security

Water Supply

Setting Out and Measuring Aids

Tools and Tool Repair / Maintenance

Equipment

Stores Control

Equipment Control and Maintenance

Employment of Casual Labour

Sections 3, 4, 13 and

15

Setting Out Setting out Horizontal Alignment Setting out Horizontal Curves Sections 3 and 4

Clearing Bush Clearing Stripping and Grubbing

Tree and Stump Removal

Boulder Removal

Job Sheet: PR(L)03

(usually not required

for R2000 rehab.)Vertical Alignment Establishment of Levels (Slotting) Job Sheet: PR(L)04

Side Drains / Formation Ditch Excavation and sloping

Camber Formation

Job Sheet: PR(L)05

Compaction Carriageway Compaction Job Sheet: PR(L)06

Other Drainage Mitre Drains

Scour Checks

Job Sheets: PR(L)07

and PR(L)08

Culvert Rehabilitation Culvert Cleaning Culvert Replacement or New

Installation

Job Sheet: PR(L)09


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5 - 4

MINISTRY OF PUBLIC WORKS

& HOUSING

Roads 2000

JOB SHEETPARTIAL REHABILITATION

(LABOUR ONLY)

Activity: BUSH CLEARING+ STRIPPING AND GRUBBING

Code: PR(L) 03

Standard: (See Contract Specifications)

Work Method:

1. Set out pegs for bush clearing, and stripping and grubbing at 10m intervals. Use the centre pegs

as reference. Use the edge pegs as chainage pegs and mark them accordingly. Do not remove

these pegs after bush clearing has been completed.

2. Tie strings along the bush clearing reference pegs.

3. Estimate the area to be cleared.

4.

Allocate tasks to the labourers. Give individual tasks for bush clearing, and stripping andgrubbing.

!2m !2m

grass cutting and grubbing

bushclearing

bushclearing

CL

A/B/C Main + Secondary Roads = 12.4 mD/E Minor Roads = 11.8 mRAR Roads = 10.5 mReduced Section RAR/Minor Roads = 9.5m

edge pegs = chainage pegs

Manpower:

1 Headman

2 Labourers for setting out

Labour Gang for BushClearing

Labour Gang for Stripping and

Grubbing

Tools + Equipment:

Tape Measure, 30 m

1 Masons Hammer

Wooden Pegs + Strings Pangas

Grass Slashers

Axes

Rakes

Jembes

Shovels

Material:

Quality Control:

Check the cleared width and ensure that the area is free of trees, bushes, shrubs, grass and roots.Productivity: Bush Clearing = 300 - 1000 m2 / day / labourer

Stripping and Grubbing = 200 - 300 m2/ day / labourer Intech 1.94/05


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5 - 5

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000


(LABOUR ONLY)

Activity: VERTICAL ALIGNMENT Code: PR(L) 04Standard: (See Contract Specifications)

Work Method:A. SET-OUT SLOTS:

1. At every 10 metre station set out in plan a slot 0.5 metres wide and length from back to back of

ditch (standard lengths see figure below) using pegs and strings.

2. Set a peg immediately on either side of the centre line peg and at right angles to the centre line

(across the road). The two pegs should be fixed approx. 20 cm above the existing road level. The

tops of the pegs should be on the same level (check with a spirit level).

CL

20

back ofditch

back ofditch

spirit level

sisal twine to setout slot 50cmwide

setting out slots = from back of ditch to back of ditch

A/B/C Main + Secondary Roads = 9.6 mD/E Minor Roads = 9.0 mRAR Roads = 7.3 mReduced Section RAR/Minor Roads = 5.5 m

B. CHECK VERTICAL ALIGNMENT:

3. Set out the vertical alignment of the road adjusting the twin pegs at each slot position as

necessary using the boning rods. The difference in alignment between any 3 consecutive slots

(20 metres) should not be more than 10 cm.

10m

10m

max.10cm

Slots

CL


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5 - 6

Work Method (Cont.):C. EXCAVATE / FILL SLOTS:

4. Fix the length of the adjustable-camber-slope-ditch-template (ACSDT) according to the relevant

cross-section (use the dimension back of ditch to back of ditch and divide by 2 to get the correctmeasurement = see diagram below). Place the ACSDT on the twin pegs to get an idea of the

extent and amount of excavation required to allow the template to si t level.

5. Cut and fill within the limits of the slot area, checking with the template and spirit level from time

to time. Material may be used on either side of the centreline. If there is insufficient material to

support the template throughout in the level position then lower the twin pegs a few cm.

Conversely if there is surplus material raise the pegs a little. Include any back sloping material in

the slot. Compact the filled material using hand rammers.

CL

back ofditch

back ofditch

spirit level

CUT

FILL

adjusted length of ACSDT

D/E Minor Roads = 4.5 mRAR Roads = 3.65mReduced RAR/Minor Roads = 2.75m

A/B/C Main + Secondary Roads = 4.8 m

6. Recheck the vertical alignment and make any adjustments necessary to the pegs. Exchange

material between adjacent slots to accommodate this adjustment in template level. The slot

profile is now that of the finished compacted road camber.

7. Mark the ditch and slope positions with pegs to the correct level using the templates, and fix

string lines, which enable the excavation quantities to be calculated and tasks to be set.

Manpower: 1 Site Supervisor (to set the

levels and check the

alignment)

1 trained Headman

3 Labourers

Tools + Equipment: Tape Measure, 30 m

1 Template (ACSDT)

1 Set Boning Rods

1 Spirit Level

1 Mason Hammer

Wooden Pegs

Strings

2 Jembes

2 Shovels

1 Pick Axe

1 Hand Rammer

Material:

Quality Control:

Check that the vertical difference from slot to slot is less than 10cm (measure over three slots)Productivity: 10 to 20 slots / day / gang

(if more slots are required then a second gang needs to be engaged)Intech 1.94/05


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5 - 7

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000

JOB SHEETPARTIAL

REHABILITATION(LABOUR ONLY)

Activity: SIDE DRAINS AND FORMATION Code: PR(L) 05Standard: (See Contract Specifications)

Work Method:

1.Calculate earthworks between slots and allocate task rates.

2.Set out pegs and strings for slopes and ditches.

3.Excavate and fill according to the established slots. Provide enough fill to allow for compaction.

4.Check ditch and slope with a wooden template.

5.Check formation with a straight edge and the ACSDT- Template and correct where necessary.

6.After compaction fill any depressions and compact again.

CL

pegs and strings to setout ditch, slope and ifnecessary backslope

check finished formationwith the ACSD-Templateand a spirit level

check levels of ditch, slope edgeand crown with boning rods, useslots as reference points

Manpower: 1 to 2 Headpersons

Labour gangs according to

task rates

Tools + Equipment:

1 Mason Hammer

Wooden Pegs and Strings

ACSD-Template, Spirit Level

Ditch-Slope Template

Straight Edge Pick Axes or Mattocks

Rakes or Spreaders

Jembes or Forked Jembes

Shovels

Wheelbarrows

Material:

Quality Control:

Check with standard ditch/slope or ACSD template the size of the ditch and camber

Ditch to be able to drain (normally minimum 2% gradient, in flat section minimum 1%9

Ditch bottom to be of uniform gradient. Use boning rods to check.Productivity: 3 - 4 m3/ day / labourer

Intech 1.94/05


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5 - 8

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000

JOB SHEETPARTIAL


Activity: COMPACTION Code: PR(L) 06Standard: (See Contract Specifications)

Work Method:

1. Mark the exact length and width of the carriageway to be compacted after the camber has been

formed.

2. Establish the number of passes (depending on the thickness of the layer, the chosen type of

compaction device and the natural moisture content).

3. Compact if possible on the same day as the camber was formed. Arrange for the gang to work

in the afternoon if necessary.

4. Check with the straight edge where depressions on the running surface appear.

5. Fill depressions on the same day and repeat compaction on these spots (material to be

borrowed from the back slope or if necessary widen the ditch).

6. Where compaction cannot be achieved on the same day, make sure it is organised as early as

possible on the next day.

Compact layers of not more than allowed thickness Depending on the equipment 4 to 12 passes are required at each point of the carriageway Passes should overlap each other Start rolling from the edge and work towards the centre-line, then repeat on the other side

overlap ofpasses

LC

Manpower: Site Supervisor to control

passes and check quality Plant Operator

1 to 2 Labourers to assist

(cleaning roller cylinder, filling

depressions, etc.)

Tools + Equipment:

Compaction Equipment Water Bowser

Straight edge, Camber Board

Jembes, Shovels, Rakes

Material:

Water for Compaction

Quality Control:

Count passes and ensure uniform rolling as indicated above (this does not replace compaction

tests). Ensure rolling only at optimum moisture content.

Productivity:

depending on equipment used. Check Section 3.4, Equipment Intech 1.94/05


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5 - 9

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000

JOB SHEETPARTIAL


Activity: MITRE DRAINS Code: PR(L) 07Standard: (See Contract Specifications)

Work Method:

1. Set out mitre drains at minimum 20 metre intervals where possible.

2. Set out mitre drains with an angle of 30-60 to the side drain and with the same width as the

side drain, but minimum 60 cm.

3. Make sure the mitre drain is leading to an open outlet, preferably between shamba

boundaries.

4. Establish gradient of mitre drain = same gradient as ditch but not less than 3%. Use boning

rods to transfer ditch gradient and line-level to establish a new gradient.

5. Excavate the ditch and make sure the gradient is uniform. The sides should be backsloped.

Dump material on the lower side of the drain.6. Provide a block in the ditch on the downhill side of the mitre drain.

roadcentreline

sidedrain

mitredrain

side drain blockedwith material frommitre drain

angle30to60

backslope

sidedrain

1 : 1 1 : 160cm

CROSS SECTION MITRE DRAIN

Manpower: 1 Headperson to set out andcontrol mitre drains

Labour gang

Tools + Equipment: Strings and pegs

Tape measure

Set of boning rods,

3 ranging rods and line level

Jembes, mattocks, shovels

Material:

Quality Control:

- Check size cross-section of drain at regular intervals

- Check gradient of mitre drain (not less than ditch)

- Check that block at mitre-drain entrance is properly filled and compacted

Productivity:

3 to 4 m3

/ day / labourer Intech 1.94/05


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5 - 10

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000

JOB SHEETPARTIAL


Activity: SCOUR CHECKS (using wooden pegs) Code: PR(L) 08aStandard: (See Contract Specifications)

Work Method:

1. Identify road sections where ditch gradient is more than 4% using a line-level = construct scour

checks.

2. Identify exact ditch gradient and space scour checks according to gradient (see drawing).

3. Cut pegs (min 50 cm long) and prepare stones for apron

4. Construct scour check with the correct profile. Use the scour check template for control.

5. Construct stone apron below scour check of min 40cm length. Dig stones into the ground.

spirit level

1st peg

template flushwith slope edge

place 1st peg at theedge of the ditch

hammer the peginto the grounduntil the spirit levelon the templateledge is horizontal

1st peg

build scour checkflush to thetemplate

provide 1 or 2 edgepegs at the outerside of the ditch

construct an apronof stones belowthe scour check ofapprox. 40cmlength

edge pegs

flush with template

Scour CheckSpacing

not required20 m10 m5 m

Gradient of Road

4% or less5%8%10%

Manpower:

1 labour gang

Tools + Equipment: Template + Spirit level

Sledge Hammer

Mason Hammer

Panga and Shovel

Material: Pegs of min. 40cm length

for scour check

Stones for apron

Quality Control:

Check spacing of the scour checks using tape measure. Maximum tolerance of + / - 0.5m.

Confirm sizes of the stakes/pegs.

Check the shape of the scour check using the scour check template.Productivity: 3 - 4 No / day / labourer (including preparation of pegs and collection of stones)

Intech 1.94/05


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5 - 11

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000

JOB SHEETPARTIAL


Activity: SCOUR CHECKS (using stones) Code: PR(L) 08bStandard: (See Contract Specifications)

Work Method:

1. Identify road sections where ditch gradient is more than 4% using a line-level = construct

scour checks.


3. Select and prepare stones (cut to shape if necessary, length minimum 35cm)



spirit level

1st stone


place 1st stone at theedge of the ditch

bury the stone intothe ground until thespirit level on thetemplate ledge ishorizontal

build scour checkflush to the template

provide 1 or 2 edgestones at the outerside of the ditch

construct an apron ofstones below the scourcheck of approx. 40cmlength

edge stone

Spacing

Gradient4% or less

5%6%7%

Spacingnot req.

20m15m10m

Gradient8%9%10%

> 10%

Spacing7.5m6m5m4m

1st stoneflush withtemplate

Manpower:

1 labour gang


Sledge and Mason Hammer

ShovelWheelbarrow

Material: Stones of min. 35cm length

for scour check

Stones for apron

Quality Control:


Confirm sizes of the stones. Check the shape of the scour check using the scour check template.Productivity: 3- 4 No / day / labourer (including collection of stones)

Intech 1.94/05


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5 - 12

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000

JOB SHEETPARTIAL


Activity: CULVERT CLEANING Code: PR(L) 09Standard:

Clean culverts of specified size including pipe barrels, the outlet/inlet structures, and the outlet

drains, keeping them free of all debris, weed, silt and any obstruction to ensure free passage of

water at all times.

Deposit debris in approved spoil dumps directed by the Engineer.

Maintain correct widths and slopes of the outlet drains. The gradient of the outlet to be checked to

ensure it is greater than 2 % using boning rods and line and level.

All broken culvert barrels to be reported to the Engineer.Work Method:

1. Check culvert inlets, barrel and outlets for silt, sand and debris (use torch to check barrel).

2. Remove material from the inlet, barrel and outlet, and dispose of material well clear of thedrainage system preferably on the lower side of the road or as instructed by the Engineer.

3. Check outlet gradient and ensure a minimum gradient of 2% using line-level and boning rod set.

Ensure that the drain bottom has a uniform gradient. Set out outlet width and length using pegs

and strings.

4. When the culvert is cleaned out check for cracks in the barrels (use torch if necessary). In case ofdamages report to the Engineer.

CL

culvert blocked withsilt and debris

repair inlet and outlet aprons includinghead and wingwalls if necessary

clean silt and debris fromoutlet, culvert and inlet

maintain same gradient asthe culvert

excavate outlet with aminimum width of 60cm

gradient2to5%

use long handled shovelor trowel for cleaning

Special Considerations:

If the culvert is severely blocked use long handled tools, like shovel and rode (iron bar 10 to

12mm, 12m long) or scoop with a bucket tied to a rope.

Tools and Equipment: Tape Measure, 30 m

Set of boning rods

Shovel, Jembe, Pick Axe, Panga

Long handled shovel + trowel

Material:

Pegs

Strings

Safety Signs and Devices

Safety Vest

Quality Control:

Visual inspection to check that the culvert, inlet and outlet are cleaned out and maintained to the

correct standard dimensions.

Check longitudinal profile of outlet using boning rods and string and line-level.

Suggested Productivity Range: Cleaning = 1/4 to 4 culvert lines / day / labourer(depending on

blockage level and length of culvert) Intech 05


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5 - 13

5.3 USING LABOUR AND INTERMEDIATE EQUIPMENT

The activities for this method are carried out by separate groups of labourers and/or

equipment, in a sequence. In this way a train of activities moves along the road improving

the carriageway and drainage in a controlled step-by-step manner.

The work is subdivided into three main operations, each carried out by a separate work gang

that follow each other in sequence:

SETTING OUT + CLEARING

1st labour gang

SHOULDER & CARRIAGEWAY

GRADING

equipment grading gang

DRAINAGE WORK

2nd labour gang


For grading either tractor towed heavy graders or motor graders can be used. The 5-tonne

towed grader has to be pulled by a 100HP tractor to be able to manage rehabilitation

grading. Compaction is achieved with either a towed dead weight or a self propelled roller.

The activities necessary for the labour and equipment partial rehabilitation approach should

be selected from the following schedule and carried out in the sequence shown:


USING LABOUR AND EQUIPMENT



Site Camp Security

Water Supply



Equipment selection, control and maint.

Stores Control



15

Setting Out Setting out Horizontal Alignment Setting out Horizontal Curves

Sections 3 and 4



Boulder Removal

Job Sheet: PR(E+L)03


for R2000 rehab.)

Shoulder Grading Ditch and Slope Grading Job Sheet: PR(E+L)04

Camber Formation Camber Grading Job Sheet: PR(E+L)05

Compaction Carriageway Compaction Job Sheet: PR(E+L)06

Side Drains Ditch Excavation Job Sheet: PR(E+L)07Other Drainage Mitre Drains

Scour Checks

Job Sheets:

PR(E+L)08 and 09

Culvert Rehabilitation Culvert Cleaning Culvert Replacement or New Installation

Job Sheet: PR(E+L)10


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5 - 14

MINISTRY OF PUBLIC WORKS

& HOUSING

Roads 2000

JOB SHEETPART. REHAB.

(EQUIPMENT ANDLABOUR)

Activity: BUSH CLEARING+ STRIPPING AND GRUBBING

Code: PR(E+L) 03


Work Method:

1. Set out pegs for bush clearing, and stripping and grubbing at 10m intervals. Use the centre

pegs as reference. Use the edge pegs as chainage pegs and mark them accordingly. Do not

remove these pegs after bush clearing has been completed.



4. Allocate tasks to the labourers. Give individual tasks for bush clearing, and stripping and

grubbing.

!2m !2m


bushclearing

bushclearing

CL



Manpower:

1 Headman


Labour Gang for Bush

Clearing Labour Gang for Stripping and

Grubbing

Tools + Equipment:

Tape Measure, 30 m

1 Masons Hammer

Wooden Pegs + Strings

Pangas Grass Slashers

Axes

Rakes

Jembes

Shovels

Material:

Quality Control:


Stripping and Grubbing = 200 - 300 m2/ day / labourerIntech 1.94/05


15/45


5 - 15

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000



Activity: SHOULDER GRADINGCode: PR(E+L) 04


Work Method:1. Set out the guide pegs for the towed grader to follow in 20 metre intervals along straight

sections and 10 metre intervals in curves. Measure the relevant width from the centre line as

shown in the table below.

CL

outer side ditch peg

centre peg

A/B/C Main + Secondary Roads = 5.40 mD/E Minor Roads = 5.10 mRAR Roads = 4.05mReduced RAR/Minor Roads = 3.55m

centre line to back of ditch

chainage peg chainage peg


2. Cut a V ditch with the grader in 1 or 4 passes and grade the shoulder. The edge of the grader

blade follows the established line of outer ditch pegs. Check the crossfall from time to time withthe AC or ACSDT -Template so that the amount of material required to form the camber can be

estimated.

3. 2 to 3 labourers accompany the grader to remove large stones, roots and to support manually

wherever necessary.

CL

V-ditch along line of pegs

grader blade

Manpower:

1 Site Supervisor

1 to 2 Grader Operators

1 Headperson + 1 labourer for

setting out

2 to 3 labourers per grader to

support

Tools + Equipment:

2 heavy towed graders + 100

HP tractors or motor grader

Tape Measure, 30 m

1 Mason Hammer

Wooden Pegs

AC- or ACSDT -Template with

Spirit Level

Material:

Quality Control: Check camber at regular intervals using AC or ACSDT templateProductivity: Together with activity Camber Formation approximately 1km / day / towed graderor 1.5 to 2km per motor grader, depending on the existing condition.

Intech 8.94/05


16/45


5 - 16

MINISTRY OF ROADS AND

PUBLIC WORKS

Roads 2000

JOB SHEETPART. REHAB.(EQUIPMENT AND

LABOUR)

Activity: CAMBER FORMATION Code:PR(E+L) 05Standard: (See Contract Specifications)

Work Method:1. Grade carriageway from edge towards centre, then from centre towards edge, with 4 to 6

passes to obtain the correct crossfall.

2. Check the achieved crossfall with the AC or ACSDT-Template and correct where necessary.

Additional material can be added if necessary by labour during the follow up drainage works.

Also check the uniformity of the fill with a straight edge.

3. Assign 2 to 3 labourers to accompany the grader to remove large stones, roots and to support

manually wherever necessary.

CL

CL

7-10%

AC or ACSDT-Template Straight Edge

Manpower: 1 Site Supervisor

1 to 2 Grader Operator


support

Tools + Equipment:


HP tractors

AC or ACSDT-Template with

Spirit Level

Straight Edge

Material:

Quality Control: Check camber at regular intervals using AC or ACSDT templateProductivity: Together with activity Shoulder Grading approximately 1km / day / towed grader

Intech 8.94/05


17/45


5 - 17

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000



Activity: COMPACTION Code: PR(E+L) 06Standard: (See Contract Specifications)

Work Method:


formed.








6. Where compaction cannot be achieved on the same day, make sure it is organised as early as

possible on the next day.


overlap ofpasses

LC

Manpower: Site Supervisor to controlpasses and check quality Plant Operator



depressions, etc.)

Tools + Equipment:

Compaction Equipment Water Bowser

Straight edge, Camber Board


Material:

Water for Compaction

Quality Control:

Count passes and ensure uniform rolling as indicated above (this does not replace compaction

tests).

Ensure rolling only at optimum moisture content.

Productivity: depending on equipment used. Check Section 3.4, EquipmentIntech 1.94/05


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5 - 18

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000



Activity: SIDE DRAINSCode:PR(E+L) 07


Work Method:1. Establish inner and outer ditch lines using pegs and strings. Set pegs at 10m intervals. Use

centre pegs or chainage pegs as reference points.

2. Excavate ditch slots every 5 to 10m. Use template to check size and shape. Slots can be used

to calculate the volume of excavation and to issue task rates.

3. Excavate/ widen the ditch according to the slots (the ditch becomes rectangular). Use material

to raise camber or to fill depressions on the carriageway if required. Otherwise cast material

well clear of the ditch, so that it will not wash back.

4. Check finished ditch using the ditch template and if necessary correct.

CLditch template

pegs in 10m intervalsalong inner ditch line

slots every 5 to10 metres


centre line to front of ditch

Manpower:

1 Site Supervisor and one

trained Headman

Labour Gang

Tools + Equipment:

3 Ranging Rods

Tape Measure, 30 m

1 Mason Hammer

Wooden Pegs and Strings Ditch or ACSDT-Template +

Spirit Level

Straight Edge

Jembes and Shovels

Mattocks

Rakes or Spreaders

Material:

Quality Control:

Check every slot using template and spirit level. Check drain after reconstruction again.

Productivity: 20 to 50 metres / day / labourer (or equivalent to 3 to 4 m3)Intech 8.94705


19/45


5 - 19

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000

JOB SHEETPARTIAL


Activity: MITRE DRAINS Code: PR(E+L) 08Standard: (See Contract Specifications)

Work Method:

1. Set out mitre drains at minimum 20 metre intervals where possible.

2. Set out mitre drains with an angle of 30-60 to the side drain and with the same width as the side

drain, but minimum 60 cm.

3. Make sure the mitre drain is leading to an open outlet, preferably between shamba boundaries.

4. Establish gradient of mitre drain = same gradient as ditch but not less than 3%. Use boning rods

to transfer ditch gradient and line-level to establish a new gradient.

5. Excavate the ditch and make sure the gradient is uniform. The sides should be backsloped.

Dump material on the lower side of the drain.

6. Provide a block in the ditch on the downhill side of the mitre drain.

roadcentreline

sidedrain

mitredrain

side drain blockedwith material frommitre drain

angle30to60

backslope

sidedrain

1 : 1 1 : 160cm

CROSS SECTION MITRE DRAIN Manpower: 1 Headperson to set out andcontrol mitre drains

Labour gang

Tools + Equipment:

Strings and pegs Tape measure

Set of boning rods,

3 ranging rods and line level

Jembes, mattocks, shovels

Material:

Quality Control:

- Check size cross-section of drain at regular intervals

- Check gradient of mitre drain (not less than ditch)

- Check that block at mitre-drain entrance is properly filled and compacted

Productivity: 3 to 4 m3/ day / labourerIntech 1.94/05


20/45


5 - 20

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000



Activity: SCOUR CHECKS (using wooden pegs) Code: PR(E+L) 09aStandard: (See Contract Specifications)

Work Method:


checks.





spirit level

1st peg




1st peg




edge pegs

flush with template

Scour CheckSpacing


Gradient of Road

4% or less5%8%10%

Manpower:

1 labour gang


Sledge Hammer

Mason Hammer

Panga and Shovel

Material: Pegs of min. 40cm length

for scour check

Stones for apron

Quality Control:




Intech 1.94/05


21/45


5 - 21

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000


(EQUIPMENT AND LABOUR)

Activity: SCOUR CHECKS (using stones) Code: PR(E+L) 09bStandard: (See Contract Specifications)

Work Method:


checks.





spirit level

1st stone


place 1st stone at theedge of the ditch





edge stone

Spacing

Gradient4% or less

5%6%

7%

Spacingnot req.

20m15m

10m

Gradient8%9%10%

> 10%

Spacing7.5m6m5m

4m


Manpower:

1 labour gang



Shovel

Wheelbarrow


for scour check

Stones for apron

Quality Control:


Confirm sizes of the stones. Check the shape of the scour check using the scour check template.Productivity:

3- 4 No / day / labourer (including collection of stones) Intech 1.94/05


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5 - 22

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000



Activity: CULVERT CLEANING Code: PR(E+L) 10Standard:



water at all times.









and strings.


CL






gradient2to5%



If the culvert is severely blocked use long handled tools, like shovel and rode (iron bar 10 to

12mm, 12m long) or scoop with a bucket tied to a rope.


Set of boning rods



Material:

Pegs

Strings


Safety Vest

Quality Control:




Suggested Productivity Range: Cleaning = 1/4 to 4 culvert lines / day / labourer(depending on

blockage level and length of culvert) Intech 05


23/45


5 - 23

5.4 USING MAINLY EQUIPMENT

The activities for this method are carried out mainly using equipment. Some labour input is

required for those activities that cannot be carried out by equipment, such as scour check

construction, culvert repair or installation, support work, etc. The work process is broken

down into a series of simple activities. The work is subdivided into three main operations,each carried out by a separate work gang that follow each other in sequence:

SETTING OUT + CLEARING equipment with labour

support

DITCH AND CAMBER GRADING grader and compactor with

labour support

OTHER DRAINAGE WORKS labour


For grading either tractor towed heavy graders or self-propelled motor graders can be used.

The 5 tonne towed grader will have to be pulled by a 100 HP tractor to be able to manage

rehabilitation grading. Compaction is achieved with either a towed dead weight roller or a self

propelled roller.

The activities necessary for the equipment partial rehabilitation approach should be selectedfrom the following schedule and carried out in the sequence shown:


USING LABOUR AND EQUIPMENT



Site Camp Security

Water Supply



Equipment selection, control and maint.

Stores Control



15

Setting Out Setting out Horizontal Alignment

Setting out Horizontal Curves

Sections 3 and 4



Boulder Removal

Job Sheet: PR(E)03


for R2000 rehab.)

Rehabilitation Grading

(heavy grading)

Cleaning / Excavating Side Drains

Cleaning / Excavating Mitre Drains

Reforming The Camber

Job Sheets: PR(E)04

and PR(E)05

Compaction Carriageway Compaction Job Sheet: PR(E)06

Other Drainage Works Scour Checks

Relief Drainage Structures Culvert Cleaning

Culvert Replacement or New Installation

Job Sheets: PR(E)09

and PR(E)10


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5 - 24

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000

JOB SHEETPARTIAL

REHABILITATION

(EQUIPMENT)

Activity: BUSH CLEARING+ STRIPPING AND GRUBBING Code: PR(E+L) 03


Work Method:

1. Set out pegs for bush clearing, and stripping and grubbing at 10m intervals. Use the centre pegs

as reference. Use the edge pegs as chainage pegs and mark them accordingly. Do not remove

these pegs after bush clearing has been completed.



4. Allocate tasks to the labourers. Give individual tasks for bush clearing, and stripping and

grubbing.

!2m !2m


bushclearing

bushclearing

CL



Manpower:

1 Headman


Labour Gang for BushClearing

Labour Gang for Stripping and

Grubbing

Tools + Equipment:

Tape Measure, 30 m

1 Masons Hammer

Wooden Pegs + Strings Pangas

Grass Slashers

Axes

Rakes

Jembes

Shovels

Material:

Quality Control:


Stripping and Grubbing = 200 - 300 m2/ day / labourer Intech 1.94/05


25/45


5 - 25

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000

JOB SHEETPARTIAL

REHABILITATION(EQUIPMENT)

Activity: CLEANING/EXCAVATING SIDE AND

MITRE DRAINS

Code: PR(E) 04


Work Method:1. Set out the guide pegs for the towed or motor grader to follow in 20 metre intervals along straight

sections and 10 metre intervals in curves. Measure the relevant width from the centre line as

shown in the table below.

2. Define where mitre drains have to be excavated, mark with pegs and discuss/agree with

landowners.

CL

outer side ditch peg

centre peg



chainage peg chainage peg


3. Drain away any standing water from carriageway and drains.

4. Cut a V ditch with the grader in 1 or 4 passes and grade the drain and shoulder.

(See detailed operation on back of Job Sheet).

5. Cut V-shape mitre drains at the pre-defined locations.

6. 2 to 3 labourers accompany the grader to remove large stones, roots and to support manually

wherever necessary.

Manpower:

1 Site Supervisor 1 to 2 Grader Operators

1 Headperson + 1 labourer for

setting out


support

Tools + Equipment:

2 heavy towed graders + 100HP tractors or self-propelled

grader

Tape Measure, 30 m

1 Mason Hammer

Wooden Pegs

AC- or ACSDT -Template with

Spirit Level

Material:

Quality Control: Check drain gradient using boning rods. Ensure uniform profile of V ditch.Productivity: Together with activity Camber Formation approximately 1km / day / towed graderor 1.5 to 2km per self-propelled grader, depending on the existing condition.

Intech 8.94/05


26/45


5 - 26

Narrow flat-bottomed ditches are not well suited tomaintenance by grader. These should be cleaned outby hand.

Graders should be used to maintain V-shaped ditchesand wide flat-bottomed ditches.

If unsuitable, material from the ditch should not normallybe graded onto the running surface. In certaincircumstances the engineer may instruct the recovery

and mixing of ditch material, where the running surfacelacks suitable fines present in the ditch

The first grading passcleans the side slope near theroad and windrows the material to the bottom of theditch.

The second grading passcleans the ditch back slopeand removes the material to the top of the ditch.

If possible, a third grading passis used to push thematerial away from the edge of the ditch, to prevent itwashing back.

Mitre Drainscan also be constructed with a grader.They lead the water away from the edge of the road andfollow closely the natural contours of the ground.

Mitre Drains should be spaced more closely as gradients

become steeper. The discharge of water should be littleand often to minimise erosion in the drains andadjoining land.


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5 - 27

MINISTRY OF ROADS AND

PUBLIC WORKS

Roads 2000

JOB SHEETPARTIAL

REHABILITATION

(EQUIPMENT)

Activity: CAMBER FORMATIONCode:

PR(E) 05


Work Method:1. Grade carriageway from edge towards centre, then from centre towards edge, with 4 to 6

passes to obtain the correct crossfall.

2. Check the achieved crossfall with the AC or ACSDT-Template and correct where necessary.

Additional material can be added if necessary by labour during the follow up drainage works.

Also check the uniformity of the fill with a straight edge.

3. Assign 2 to 3 labourers to accompany the grader to remove large stones, roots and to support

manually wherever necessary.

CL

CL

7-10%

AC or ACSDT-Template Straight Edge

Manpower: 1 Site Supervisor

1 to 2 Grader Operator


support

Tools + Equipment:


HP tractors

AC or ACSDT-Template with

Spirit Level

Straight Edge

Material:

Quality Control:

Check camber at regular intervals using AC or ACSDT templateProductivity: Together with activity Shoulder Grading approximately 1km / day / towed grader

Intech 8.94/05


28/45


5 - 28

Heavy Grading to Restore the Camber:

CL

CL

C

C

Heavy grading requires additional passes to achieve the required camber. Workshould be completed on one side of the road at a time. Start grading from roadshoulder and work your way towards the centre line.

An even number of passes should be used to avoid a flat finished crown (centre ofroad).

Normally initial cutting passes are required to bring the material in from the edgesof the road towards the centre.

Spreading passes are required to redistribute the material away from the crowntowards the shoulder.

Source: PIARC, International Road Maintenance Handbook


29/45


5 - 29

MINISTRY OF PUBLIC

WORKS & HOUSING

Roads 2000


(EQUIPMENT)

Activity: COMPACTION Code:PR(E) 06Standard: (See Contract Specifications)

Work Method:


formed.








6. Where compaction cannot be achieved on the same day, make sure it is organised as early aspossible on the next day.


overlap ofpasses

LC

Manpower: Site Supervisor to control

passes and check quality Plant Operator



depressions, etc.)

Tools + Equipment:

Compaction Equipment

Water Bowser Straight edge, Camber Board


Material: Water for Compaction

Quality Control: Count passes and ensure uniform rolling as indicated above (this does not replace compaction

tests).

Ensure rolling only at optimum moisture content.

Productivity: depending on equipment used. Check Section 3.4, Equipment Intech 1.94/05


30/45


5 - 30

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000


(EQUIPMENT)

Activity: SCOUR CHECKS (using wooden pegs) Code: PR(E) 09aStandard: (See Contract Specifications)

Work Method:


checks.





spirit level

1st peg




1st peg




edge pegs

flush with template

Scour CheckSpacing


Gradient of Road

4% or less5%8%10%

Manpower:

1 labour gang


Sledge Hammer

Mason Hammer

Panga and Shovel

Material: Pegs of min. 40cm length for scour

check

Stones for apron

Quality Control:




Intech 1.94/05


31/45


5 - 31

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000


(EQUIPMENT)

Activity: SCOUR CHECKS (using stones) Code: PR(E) 09bStandard: (See Contract Specifications)

Work Method:


checks.





spirit level

1st stone

template flush

with slope edge place 1st stone at theedge of the ditch





edge stone

Spacing

Gradient4% or less

5%

6%7%

Spacingnot req.

20m

15m10m

Gradient8%9%

10%> 10%

Spacing7.5m6m

5m4m


Manpower:

1 labour gang



Shovel

Wheelbarrow


for scour check

Stones for apron

Quality Control:


Confirm sizes of the stones.

Check the shape of the scour check using the scour check template.Productivity: 3- 4 No / day / labourer (including collection of stones)

Intech 1.94/05


32/45


5 - 32

MINISTRY OF ROADS &

PUBLIC WORKS

Roads 2000

JOB SHEETPARTIAL

REHABILITATION(EQUIPMENT)

Activity: CULVERT CLEANING Code: PR(E) 10Standard:



water at all times.









and strings.


CL






gradient2to5%



If the culvert is severely blocked use long handled tools, like shovel and rode (iron bar 10 to12mm, 12m long) or scoop with a bucket tied to a rope.


Set of boning rods



Material:

Pegs

Strings


Safety Vest

Quality Control:




Suggested Productivity Range: Cleaning = 1/4 to 4 culvert lines / day / labourer(depending onblockage level and length of culvert)

Intech 05


33/45


5 - 33

5.5 SPOT IMPROVEMENT

Spot improvement operations can be very varied as the defect situations also vary greatly.

However, very common defects are short sections of roads that have been flooded or

structures that are damaged and impassable.

In terms of work implementation, spot improvement operations are technically andmanagerially challenging.

Wherever possible spot improvement work is carried out using principally labour-based

methods. Equipment will be mainly required for the haulage of material, such as gravel,

stones, chipping, etc., and for compaction.

The nature of spot improvement work changes from case to case and requires careful

planning and monitoring by the District Engineer or hired Consultant. The Contractor may be

confronted with a number of different possible operations as described in the following list:

5.5.1 Reconstruction of a Road Section

Roads are occasionally impassable due to short sections, which have completely failed. Inmost cases such sections have been swept away by floods or the effect of heavy rains and

the road section requires full reconstruction.

!The construction methods for Rural Access and Minor Roads are

described in detail in the Technical Manual, Volume I, Minor

Roads Programme.

A contractor carrying out full labour-based reconstruction of short road sections requires the

following main resources on site:

One or two fully trained and qualified Site Supervisors Number of competent (on-the-job trained) Headmen/women

Handtool set for approximately 50 to 80 labourers

Two to three tractors with trailers or two tipper trucks (exact number depends on hauling

distance)

One 3 to 5 tonne dead weight roller or two pedestrian vibrating rollers

One towed water bowser

One pick-up for supervision and transport of smaller items

Site camp facilities (stores, office, accommodation for staff)

5.5.2 Regravelling of a Road Section:

The main defect on the classified unpaved road network is the missing or insufficient gravel

layer. This are usually steep sections or sections with weak sub-grades, like black cotton soil.

The contract document specifies the detailed standards to be achieved for gravelling works

of a particular contract and road. If labour-based methods are used, the work execution is the

same as for the Rural Access and Minor Roads Programme.

!The labour-based gravelling methods for Rural Access and

Minor Roads are described in detail in the Technical Manual,

Volume I, Minor Roads Programme.

A contractor carrying out regravelling of short road sections using labour-based methods

requires the following main resources on site:


34/45


5 - 34

One or two fully trained and qualified Site Supervisors

Number of competent (on-the-job trained) Headmen/women

Handtool set for approximately 50 labourers

Two to three tractors with trailers or two tipper trucks (exact number depends on hauling

distance) One 3 to 5 tonne dead weight roller or two pedestrian vibrating rollers

One towed water bowser



!If the road section is longer than 2km, additional hauling equipment is required.

In cases where the gravelling work is carried out using mainly equipment the following

resources are required:

One fully trained and qualified Site Supervisors

One or two competent (on-the-job trained) Headmen/women

Handtool set for approximately 10 labourers

One dozer and one front end loader for gravel excavation and loading

Three to four tractors with trailers or three to four tipper trucks (exact number depends on

hauling distance)

One 3 to 5 tonne dead weight roller or one self-propelled vibrating roller

One water bowser with spraying bar



!If the road section is longer than 2km, additional hauling equipment is required.

! Note: using equipment for short sections of regravelling mayonly be economical if local labour is not available.

5.5.3 Rehabilitation of a Single Barrel Culvert:

Non-functional culverts are a very common problem on existing roads and often need to

repaired or replaces

There are three basic culvert installation situations and they each require separate

arrangements depending on the outfall gradient:

A- Flat Outfall (10% approx.)


35/45


5 - 35

Culvert Type A; Flat Outfall

This should be used in flat areas and watercourses with shallow gradients. In these

circumstances a culvert set tool low would simply silt up. A culvert set too high would

cause silting upstream and possibly erosion problems in the outfall.

The road has to be built up over the culvert using a ramp/embankment. The verticalalignment must be adjusted.


36/45


5 - 36

Culvert Type B; Intermediate Outfall

This arrangement should be used when the outfall gradients are between 5% and 10%

approximately. The culvert may be excavated slightly into the existing ground and the

outfall ditch will be of reasonable length. However, the road will still require to be built upover the culvert barrel with gentle ramps of less than 5% extending at least 20 metres

either side of the culvert.


37/45


5 - 37

Culvert Type C; Steep Outfall

On steep sidelong ground (above 10%) the culvert can be installed without adjusting the

vertical alignment of the road. The culvert barrel may be buried and adequate cover

achieved with an outfall ditch or reasonable length. A suitable drop pit will need to be

constructed at the culvert inlet. It should be large enough to allow later access formaintenance of the culvert barrel. At the outlet, particular attention should be given to

preventing erosion, particularly on steep slopes and easily erodible soils.


38/45


5 - 38

Culvert Installation:

The exact site of the culvert should be determined at each low point in the vertical alignment

and at each location where a relief or crossover culvert is required. These locations have to

be determined by the Engineer and the Contractor to be instructed accordingly.

The next step is to determine the type of installation arrangement required: A, B or C, so thatthe culvert may be correctly set out. The following provides guidance on this procedure

taking a 5.40m wide road (carriageway width) as an example:

PROCEDURE FOR SETTING OUT 60 CM CULVERT

If the culvert site is flat check the watercourse gradient for 20 metres downstream form the

location of the culvert outlet. Use boning rods and Abney Level, or line level, for this

purpose. If the gradient is less than 5% (1m fall in 20m), then construct the culvert in

arrangement Type A with the culvert inverts as close to the existing ground/water course

level as possible, use guidelines of Figure G.1. Also construct arrangement Type A, if the

height of the embankment fill (measured to edge of running surface) at the culvert is atleast 1.1m. Otherwise proceed with the following steps to install arrangements Type B or

C.


39/45


5 - 39

Culvert Bedding:

The culvert must be bedded on stable material. Firm clay or sandy material is suitable. We,

soft or organic material should be excavated and replaced with fine murram (gravel). Large

stones could damage the culvert rings under loading and must not be allowed in contact with

the rings. They should be removed, or covered with suitable material. If necessary murram

(gravel) containing stones up to 20mm, or concrete, may be used to bed the culvert rings.

The culvert bed should be excavated to give continuous support over the lower third of the

barrel. The shape of the bed should be controlled with a culvert template (see following

Figure). The gradient should be controlled using boning rods and the established excavation

pegs.


40/45


5 - 40

PROCEDURE FOR CONSTRUCTION AND CONTROLLING CULVERT BED

Backfilling should be carried out in layers of about 15cm compacted with hand rammers.

Material must be particularly compacted against the culvert rings to avoid later settlement.

Care must be taken that stones larger than 20mm are not placed in contact with the rings.

The backfill cover requirements as detailed in the contract specifications (3/4 of barrel

diameter minimum) must be ensured.

Where the road has to be kept open to traffic, the culvert may be constructed in two halves.

Care must be taken to protect the culvert works, and the traffic both during and after working

hours. Suitable warning signs and barricades should be placed.

Required Resources:

A contractor carrying out culvert rehabilitation works requires the following main resources on

site:


Handtool set for approximately 5 to 8 labourers

One tractor with trailer or one flat-bed/tipper truck (depends on hauling distance) for

transporting culvert rings or material to cast culverts on site.

One small concrete mixer for cases where culverts have to be haunched.



41/45


5 - 41

5.6 SMALL STRUCTURE WORKS

Missing or defective structures are often the cause for impassable roads and are therefore

the critical spots in the road network. It is advisable to construct wherever possible multiple

culvert lines, drifts or simple structures instead of bridges. These have three main

advantages:- they are cheaper,

- they can be built using locally available resources, and

- they can be easier maintained.

A contractor carrying out structure works requires the following main resources on site:


Handtool set for up to 20 labourers

Form work material for concrete structure elements

One tractor with trailer or one flat-bed/tipper truck (depends on hauling distance) for

transporting culvert rings or material to cast culverts on site.

One concrete mixer (size depending on the amount of concrete to be mixed) One concrete vibrator with one 40mm and one 60mm needle.



! For technical and operational information on concrete andmasonry works refer to Sections 7 and 8 of this Handbook.

5.7 RECONSTRUCTION OF GRAVEL SHOULDERS ON BITUMEN ROADS

Most shoulders along the bitumen roads of Kenya are unpaved. Gravel shoulders are subject

to constant wear and tear by vehicle and animal traffic and to softening and erosion by

surface water. Edge repair and shoulder regravelling are usually dealt with in one operation.

Where edge repair is not necessary and only shoulder regravelling needs to be carried out,

the work procedure is the same as detailed in method 1 of the work description presented

below:

Work Description (Method 1)

Define the depth of the shoulder erosion

and check whether the base or even the

sub-base is affected.ShoulderBase

Sub-base

Surfacing

SHOULDER TO STANDARD

If base and sub-base are not affected,

regravel the shoulder and then repair the

edge (see method 1).

SURFACE EDGE BROKEN ANDSHOULDER ERODED


42/45


5 - 42

If the base and sub-base are affected, first

repair the entire shoulder including the base

and sub-base and then the road edge (see

method 2).SURFACE EDGE BROKEN, SHOULDERERODED, BASE AND SUB-BASEDEFECTIVE

Dig and remove all unstable material

(surface and shoulder) to the depth of the

base.

Brush out and clean the area.

Loosen the existing shoulder gravel to allow

a key for the added material.

Add new gravel in layers of not more than

10 cm to shoulder, add water if necessaryand compact with hand rammer or hand

roller.

Allow for some surplus material (level of

shoulder to be slightly higher than surface)

for later settlement.

Make sure the crossfall of the shoulder is

the same as for the carriageway.

Remove excess material for further use and

clear the section of debris.

Mark out the line along the road edge to be

cut. Cut a trench of about 8 cm width and 8

cm depth into the base. Make sure the sides

are vertical.

Brush out and clean the excavation area.

Apply a prime coat to the surface of the

excavated area. Make sure edges of patch

are well coated.

Place premix carefully in the edge trenchand rake the material to the correct level.

Compact the premix thoroughly. The

surface of the new edge should stand

approximately 5 mm above the existing road

surface after compaction.

The surface of the patch must be dusted or

sanded just before the final compaction

pass to prevent pick-up by vehicles.

After 3 days or more the patch must be

sealed by applying bitumen emulsion and a

single layer of 6 mm chippings. The

chippings must be well rolled.


43/45


5 - 43

Work Description (Method 2)

Dig and remove all unstable material until

you find firm material. Level the area.

Brush out and clean the area.

Rebuilt the base and sub-base using the

same material. Compact thoroughly.

Rebuilt the shoulder as described in

method 1.

Repair the surface edge as described in

method 1.

Required Resources:

A contractor carrying out shoulder and bitumen edge rehabilitation works requires the

following main resources on site:


Handtool set for 10 to 10 labourers. If labour is used for excavation, loading and spreading

of gravel up to 50 labourers require tools.

Two to three tractors with trailer or two to three tipper trucks (depending on hauling

distance) for transporting gravel for shoulder repair.

Dozer and Loader for gravel excavation and loading if equipment is used.

One grader for spreading shoulder gravel, if equipment is used. One bitumen emulsion hand sprayer

One pedestrian vibrating roller


For larger sites camp facilities (stores, office, accommodation for staff)

Depending on the existing surface and base composition, additional material will be required

to carry out the repair work. In most places the following material will be used:

lime (for stabilisation of base)

tack coat (for spaying the prime coat)

bituminous premix (for the edge repair)

bitumen emulsion (for patch seal) chippings, 6 mm (for patch seal)


44/45


5 - 44

5.8 QUALITY CONTROL

For Contractors it is advisable to maintain an own quality control system that ensures

constant checking through all working steps. It is in the interest of the Contractor to detect

any shortcomings as early as possible so that rectifications can be carried out at low cost.

The following tables provide practical quality control measures for the most important workitems for labour-based road works.

ROAD DIMENSION TESTS

(i) Type of tests:Simple checks on the dimensional accuracy of the construction works.

(ii) Methods used:Tapes and/or templates are used to measure the completed works.

Test Method Location Test Interval(every ..)

Tolerance

Width of carriage way sub-base terrace(excavation to level) tape field 100m +/- 50mm

Width and depth of side drains template field 10m +/- 20mm

ROAD PROFILE TESTS

(i) Type of tests:Checks on the camber and longitudinal profile of the carriageway.

(ii) Methods used:Camber boards, boning rods and/or levelling instrument are used to measure the completedbase and surface layer.


Tolerance

Camber template field 20m +/- 10mm

Longitudinal profile boningrods

field 20m +/- 50mm

GRAVEL SOURCE TESTS (FOR BASE LAYER)

(i) Type of tests:Check on the suitability of a gravel source for surface layer. Unlike most other tests, the clientcan only carry out these tests in the laboratory before construction commences. However, ifyou are doubtful about the quality of the material you may use a simple field test to identify the

suitability of the chosen gravel. If the test described below shows doubtful results, then theclient should be consulted for further instructions.

(ii) Methods used:

- Bottle test to identify the grading.- Moulding and drying test to identify plasticity and strength

Test Method Location When? Tolerance

Grading bottle field when in doubtof quality

NA

Plasticity moulding field when in doubtof quality

NA

Strength drying field when in doubtof quality

NA


45/45


GRAVEL LAYER TESTS (FOR BASE OR SURFACE LAYER)

(i) Type of tests:Tests on the thickness and degree of compaction of the finished base layer.

(ii) Methods used:- Tapes are used to measure the gravel thickness.

- Special laboratory tests are used by the client to measure the degree of compaction. A simpleway of ensuring the compaction is achieved is by ensuring that the required minimum number ofcompaction passes, at optimum moisture content, are actually made. This method does not

provide the contractor with the actual result but ensures that the desired compaction is achievedin most cases.


Tolerance

Thickness of gravel layer tape field 50 m (in centreand towards

edge)

+/- 10 mm

Degree of compaction countingcompaction

passes

field always 0

Field Density Test For Gravel Layers

To control whether the required compaction has been achieved density tests have to be

regularly taken during the construction period. This is part of the measurement procedure of

the client or his representative.

However, as a contractor you are also interested to find out yourself:

whether the density specified in the contract has been achieved before the clientmeasures, and

what the minimum compaction operation is to achieve this required density so that you do

not carry out more work and spend more money then what is actually required.

For large-scale contracts the contractors are required to establish a site laboratory whereboth the client and the contractor can carry out the tests. For small-scale contracts,

where mainly labour is used, such laboratories are usually not set up. However, tests canstill be carried out, for example by using the laboratory facilities of Road Departments or

Material Departments.

!Several methods are used for determining the achieved field

density. These are explained in Section 6 of this Hand Book.

Quality control checks for concrete works and mortar are

provided in Sections 7 and 8 respectively.

05 rehabilitation works

Documents