Republic of the Union of Myanmar

Low Volume Rural Road

Design Manual

Ministry of Construction
Department of Rural Road Development

2020
 Foreword

Low Volume Rural Roads (LVRR)s provide important links from homes, villages and farms to markets and offer the
public access to health, education and other essential services. These roads also provide important links between rural
communities and the main Myanmar road network.

There is a wealth of local and international information, experience and research that when utilised, can change past
practices and thinking and provide Myanmar with an enhanced and affordable rural road network. To benefit fully
from these advances and to see necessary improvements implemented on the ground, the Ministry of Construction,
Department of Rural Road Development (DRRD) has in partnership with the UKAID-Funded ReCAP initiative
commissioned this comprehensive national road design manual specifically for low volume roads.

Compilation of the documents was undertaken by H.P. Gauff Ingenieure GmbH & Co. KG -JBG- in close cooperation
with technical specialists from DRRD and with the key input from representatives from the Ministry of Construction,
other key ministries, local industry, national and local authorities and other relevant road projects funded by World
Bank, ADB, KfW and JICA. Local experience was a vital component on the geometric, earthwork, drainage, pavement
and safety issues for this volume.

This Manual has been structured in such a way that it can be easily updated and, in this context, can be considered a
living document to be amended and improved as additional key research, information and experience becomes
available.

On behalf of the Ministry of Construction and DRRD I would like to take this opportunity to thank the Department for
International Development (DFID) of the United Kingdom, the ReCAP/AsCAP team for support in the development of
the Myanmar Low Volume Rural Roads Design Manual. I would also like to extend my gratitude and appreciation to
all of the industry stakeholders and participants who contributed their time, knowledge and effort during the
development of the documents.

I trust that the Myanmar Low Volume Rural Roads manual will provide the essential information needed to guide our
road asset managers and design engineers in the provision of an appropriate and sustainable rural road network.

His Excellency Han Zaw

Minister of Construction

Design Manual for Low Volume Rural Roads in Myanmar i

 Preface

Purpose

The purpose of the Manual is to serve as a nationally recognised document, the application of which is deemed to
serve as a standard reference and ready source of good practice for the planning, investigation, design and
construction of low volume rural roads (LVRR)s in Myanmar. In so doing, it will assist practitioners in developing the
country’s LVRR network in a cost effective, environmentally optimized and sustainable manner and hence support the
Myanmar Government’s objectives for rural development as defined in the National Strategy for Rural Roads and
Access.

This Design Manual provides practical guidance to roads practitioners responsible for the design of low traffic earth,
gravel or paved roads throughout Myanmar. The Manual has been drafted to be fully adaptable for use by different
stakeholders, at national, state, township and local level administered by authorities, enterprises or communities.

How To Use This Manual

This manual is designed to help you locate information quickly and easily. Each Chapter contains the following
information:

SECTION A: KEY PRINCIPLES Chapter 1 Introduction

Chapter 2 Policy, Standards and Specifications
Chapter 3 The Approach to LVRR Design
Chapter 4 Myanmar Road Environments

SECTION B: DESIGN Chapter 5 Ground Investigations

Chapter 6 Geometric Design
Chapter 7 Surfacing and Pavement Design
Chapter 8 Construction Materials
Chapter 9 Cross Drainage and Small Structures
Chapter 10 Earthworks
Chapter 11 Design Process

SECTION C: IMPLEMENTATION Chapter 12 Construction

Chapter 13 Asset Management
Chapter 14 Technical Audit

Design Manual for Low Volume Rural Roads in Myanmar ii

 Acknowledgements

We would like to acknowledge the contribution of the AsCAP partner DRRD and particularly the staff in the district and
state offices of DRRD, project consultant staff of Rural Road and Access Project and Rural Development Program RRAP
and RDP for all their assistance and sharing of information. We further thank all stakeholder organisations and
development cooperation partners for their time and information shared.

Design Manual for Low Volume Rural Roads in Myanmar iii

 Abbreviations and Acronyms
$ United States Dollar (US$ 1.00 ≈ provide conversion to local currencies)

£ GBP – Great Britain Pounds (£ 1.00 ≈ MK 2,024.0)

AADT Annual Average Daily Traffic
ADT Average Daily Traffic
ARRB Australian Road Research Board
AASHTO American Association of State Highway and Transportation Officials
ADB Asian Development Bank
AfCAP Africa Community Access Partnership
AfDB African Development Bank
AFNOR Association Française de Normalisation
ARI Average Return Interval
AsCAP Asia Community Access Partnership
ASTM American Society for Testing and Materials
BMMS Bridge Maintenance Management System
BoQ Bill of Quantities
CPT Cone Penetration Test (“Dutch” Cone)
CBR California Bearing Ratio
CRD Central Road Database
CRRN Core Rural Road Network
CS Cape Seal
DBM Dry-Bound Macadam
DBST Double Bitumen Surface Treatment
DCP Dynamic Cone Penetrometer
DCS Double Chip Seal
DDG Deputy Director General
DEM Digital Elevation Model
DFID Department for International Development
DG Director General
DoLIDAR Department of Local Infrastructure Development and Agricultural Roads
DPBANRD Department of Progress of Border Areas and National Races Development
DRD Department of Rural Development (DOALI)
DRRD Department of Rural Road Development (MoC)
DOB Department of Bridges (MoC)
DOH Department of Highways (MoC)
DOS Double Otta Seal
DOT Department of Transportation
ECD Environmental Conservation Department
EOD Environmentally Optimised Design

Design Manual for Low Volume Rural Roads in Myanmar iv

 EHP Eastern Highland Province
EHS Environmental Health and Safety
EIA Environmental Impact Assessment
ENS Engineered Natural Surface
EOD Environmentally Optimised Design
esa equivalent standard axles
FED Final Engineering Design
FHWA Federal Highway Administration
FMS Flood Management System
FS Feasibility Study
GIS Geographical Information System
GM Grading Modulus
GoM Government of Myanmar
GPS Global positioning system
GWC Gravel Wearing Course
HPS Hand-Packed Stone
IDF Intensity Duration Frequency
IEE Initial Environmental Examination
IFC International Finance Corporation
IFI International Finance Institute
IMT Intermediate Transport
JICA Japan International Cooperation Agency
KfW Kreditanstalt für Wiederaufbau (German Development Bank)
LIC Lower Income Country
LVR Low Volume Road
LVRR Low Volume Rural Road
LVRRDM Low Volume Rural Road Design Manual
LWC Low-Water Crossing
masl meter above sea level
MCEA Myanmar Construction Entrepreneur Association
MES Myanmar Engineering Society
mesa million equivalent standard axles
MLDM Myanmar LVRR Design Manual
MOALI Ministry of Agriculture, Livestock and Irrigation
MOBA Ministry of Border Affairs
MoC Ministry of Construction
MOECAF Ministry of Environmental Conservation and Forestry
MONREC Ministry of Natural Resources and Environmental
NASA National Space Agency (USA)
NCDDP National Community Driven Development Project

Design Manual for Low Volume Rural Roads in Myanmar v

 NCDP National Comprehensive Development Plan
NEQG National Environmental Quality Guidelines
NMT Non-Motorised Traffic
NRC Non-reinforced Concrete
NSRRA National Strategy for Rural Road and Access
ORN Overseas Road Note
PCU Passenger Carrier Unit
PED Preliminary Engineering Design
PFS Pre-Feasibility
PMMS Pavement Maintenance Management System
PMU Project Management Unit
QA Quality Assurance
QC Quality Control
RAI Rural Access Index
RAMS Road Asset Management System
RDU Research and Development Unit
ReCAP Research for Community Access Partnership
RFP Request for Proposal
RMMS Routine Maintenance Management System
RRAP Rural Road and Access Project (DRRD with ADB funding)
RTS Road Transport Services
SBL Sand Bedding Layer
SAD Self-administered division
SADC Southern African Development Committee
SANRAL South African National Roads Agency
SAZ Self-administered zone
SCS Single Chip Seal
SBST Single Bituminous Surface Treatment
SDAC Standards of Decision-Making Across Cultures
SDG Sustainable Development Goal
SE Super-Elevation
SEACAP Sustainable Energy Access and Climate Action Plan
SlS Slurry Seal
SME Small or Medium Enterprise
SMS Safety Management System
SOS Single Otta Seal
SPT Standard Penetration Testing
SS Sand Seal
STRM Security Threat Response Manager (software)
SuM4ALL Sustainable Mobility for All

Design Manual for Low Volume Rural Roads in Myanmar vi

 TAM Technical Audit Team
TDC Township Development Committee
TL Team Leader
ToR Terms of Reference
TRL Transport Research Laboratory
UCS Unconfined Compression Test
UK United Kingdom (of Great Britain and Northern Ireland)
UKAid United Kingdom Aid (Department for International Development, UK)
USAid United States Agency for International Development
VAR Vent-Area Ratio
VDC Village Development Committee
VOC Vehicle Operating Costs
VEF Vehicle Electric Flow
WB World Bank
WBM Water-Bound Macadam
WFB Western Fold Belt
WHO World Health Organisation
WLAC Whole Life Asset Cost
WLC Whole-Life Cost

Design Manual for Low Volume Rural Roads in Myanmar vii

 Manual Updates

Significant changes to criteria, procedures or any other relevant issues related to new policies or revised laws of the
land or that are mandated by the relevant national or state Ministry or Agency should be incorporated into the
manual from their date of effectiveness.

Other minor changes that will not significantly affect the whole nature of the manual may be accumulated and made
periodically. When changes are made and approved, new page(s) incorporating the revision, together with the
revision date, will be issued and inserted into the relevant chapter.

The road sector is encouraged to not only to put into practice this initial version of the Myanmar Low Volume Roads
Manual but to feed back to the MoC Director any suggestions for future updates.

Ministry of Construction, Department of Rural Road Development

LVRR Manual: Change Control

MANUAL UPDATE To be completed by DRRD

Chapter Change Number

Section Explanation Modification

Table
Figure
Page

Design Manual for Low Volume Rural Roads in Myanmar viii

 GLOSSARY OF TECHNICAL TERMS

Aggregate (for construction)

A broad category of particulate material including sand, gravel, crushed stone, slag and recycled material that forms a
component of composite materials such as concrete and pre-mix asphalt.

Apron
The flat invert of the culvert inlet or outlet.

Asphalt
A mixture of inert mineral matter, such as aggregate, mineral filler (if required) and bituminous binder in
predetermined proportions (sometimes referred to as Asphaltic Concrete or Asphalt Concrete). Usually pre-mixed in a
plant before transport to site to be laid and compacted. Expensive and usually only used on main roads. Also used as
an alternative term for Bitumen in some regions, and may be a petroleum processing product or naturally occurring in
deposits.

Atterberg Limits
Basic measures of the nature of fine-grained soils which identify the boundaries between the solid, semi- solid, plastic
and liquid states.

Basin
A structure at a culvert inlet or outlet to contain turbulence and prevent erosion.

Berm
A low ridge or bund of soil to collect or redirect surface water.

Binder, Bituminous
Any bitumen based material used in road construction to bind together or to seal aggregate or soil particles.

Binder, Modified
Bitumen based material modified by the addition of compounds to enhance performance. Examples of modifiers are
polymers, such as PVC, and natural or synthetic rubbers.

Bitumen
A non-crystalline solid or viscous mixture of complex hydrocarbons that possesses characteristic agglomerating
properties, softens gradually when heated, is substantially soluble in trichlorethylene and is usually obtained from
crude petroleum by refining processes. Referred to as Asphalt in some regions.

Bitumen, Cutback
A liquid bitumen product obtained by blending penetration grade bitumen with a volatile solvent to produce rapid
curing (RC) or medium curing (MC) cutbacks, depending on the volatility of the solvent used. After evaporation of the
solvent, the properties of the original penetration grade bitumen become operative.

Bitumen, Penetration Grade

That fraction of the crude petroleum remaining after the refining processes which is solid or near solid at normal air
temperature and which has been blended or further processed to products of varying hardness or viscosity.

Bitumen emulsion
A mixture of bitumen and water with the addition of an emulsifier or emulsifying agent to ensure stability.
Conventional bitumen emulsion most commonly used in road works has the bitumen dispersed in the water. An
invert bitumen emulsion has the water dispersed in the bitumen. In the former, the bitumen is the dispersed phase
and the water is the continuous phase. In the latter, the water is the dispersed phase and the bitumen is the
continuous phase. The bitumen is sometimes fluxed to lower its viscosity by the addition of a suitable solvent.

Design Manual for Low Volume Rural Roads in Myanmar ix

Bitumen Emulsion, Anionic
An emulsion where the emulsifier is an alkaline organic salt. The bitumen globules carry a negative electrostatic
charge.

Bitumen Emulsion, Cationic

An emulsion where the emulsifier is an acidic organic salt. The bitumen globules carry a positive electrostatic charge.

Bitumen Emulsion Grades

Premix grade: An emulsion formulated to be more stable than spray grade emulsion and suitable for mixing
with medium or coarse graded aggregate with the amount smaller than 0.075mm not
exceeding 2%.
Quick setting grade: An emulsion specially formulated for use with fine slurry seal type aggregates, where quick
setting of the mixture is desired.
Spray grade: An emulsion formulated for application by mechanical spray equipment in chip seal
construction where no mixing with aggregate is required.
Stable mix grade: An emulsion formulated for mixing with very fine aggregates, sand and crusher dust. Mainly
used for slow-setting slurry seals and tack coats.

Black Cotton Soil

An expansive clay found widely in the North East of the country that expands and loses most of its strength when
wetted.

Blinding
(a) A layer of lean concrete, usually 5 to 10 cm thick, placed on soil to seal it and provide a clean and level working
surface to build the foundations of a wall, or any other structure.
(b) An application of fine material e.g. sand, to fill voids in the surface of a pavement or earthworks layer.

Brick (fired clay)

A hard durable block of material formed from burning (firing) clay at high temperature.

Bridge
A structure usually with a span of 5 metres or more, providing a means of crossing above water, a railway or another
obstruction, whether natural or artificial. A bridge consists of abutments, deck and sometimes wingwalls and piers, or
maybe an arch.

Camber
The road surface is normally shaped to fall away from the centre line to either side. The camber is necessary to shed
rain water and reduce the risk of passing vehicles colliding. The slope of the camber is called the Crossfall. On sharp
bends the road surface should fall directly from the outside of the bend to the inside (superelevation).

Cape Seal
A multiple bituminous surface treatment that consists of a single application of binder and stone followed by one or
two applications of slurry.

Carriageway
The road pavement or bridge deck surface on which vehicles travel.

Cascade
A drainage channel with a series of steps, sometimes with intermediate silt traps or ponds, to take water down a
steep slope.

Catchpit
A manhole or open structure with a sump to collect silt.

Design Manual for Low Volume Rural Roads in Myanmar x

Catchwater Drain
See Cut-off.

Causeway or Vented Drift

Low level structure constructed across streams or rivers with openings to permit water to pass below road level. The
causeway may become submerged in flood conditions.

Cement (for construction)

A dry powder which on the addition of water (and sometimes other additives), hardens and sets independently to
bind aggregates together to produce concrete. Cement can also be used to stabilise certain types of soil. Cement is
also sometimes used as a fine filler in bituminous mixes.

Chippings
Clean, strong, durable pieces of stone made by crushing or napping rock. The chippings are usually screened to obtain
material in a small size range.

Chip Seal, Single

An application of bituminous binder followed by a layer of stone or clean sand. The stone is sometimes covered with a
fog spray.

Chip Seal, Double

An application of bituminous binder and stone followed by a second application of binder and stone or sand. The
second seal usually uses a smaller aggregate size to help key the layers together. A fog spray is sometimes applied on
the second layer of aggregate.

Chute
An inclined pipe, drain or channel constructed in or on a slope.

Cobble Stone (Dressed stone)

Cubic pieces of stone larger than setts, usually shaped by hand and built into a road surface layer or surface
protection.

Coffer Dam
A temporary dam built above the ground to give access to an area which is normally, or has a risk of being, submerged
or waterlogged. Cofferdams may be constructed of soil, sandbags or sheet-piles.

Collapsible soil
Soil that undergoes a significant, sudden and irreversible decrease in volume upon wetting.

Compaction
Reduction in bulk of fill or other material by rolling or tamping.

Complimentary Interventions
Actions or initiatives that are implemented through a roads project which are targeted toward the communities that
lie within the influence corridor of the road and are intended to optimise the benefits brought by the road and to
extend the positive and mitigate the negative impacts of the project.

Concrete
A construction material composed of cement (most commonly Portland cement, but occasionally using other available
cementitious materials such as fly ash and slag cement), aggregate (generally a coarse aggregate such as gravel or
crushed stone plus a fine aggregate such as sand), water, (and sometimes chemical admixtures to improve
performance or for special applications).

Design Manual for Low Volume Rural Roads in Myanmar xi

Concrete Block Paving
A course of interlocking or rectangular concrete blocks placed on a suitable base course and bedded and normally
jointed with sand.

Counterfort Drain
A drain running down a slope and excavated into it. The excavation is partly or completely filled with free draining
material to allow ground water to escape.

Cribwork
Timber or reinforced concrete beams laid in an interlocking grid, and filled with soil to form a retaining wall.

Crossfall
See Camber

Crushed Stone
A form of construction aggregate, typically produced by mining a suitable rock deposit and breaking the removed rock
down to the desired size using mechanical crushers, or manually using hammers.

Curing
The process of keeping freshly laid/placed concrete moist to prevent excessive evaporation with attendant risk of loss
of strength or cracking. Similarly with cement or lime stabilised layers, the measures to minimise moisture loss during
the initial period of strength development.

Cut-off/Catchwater Drain
A ditch constructed uphill from a cutting face to intercept surface water flowing towards the road.

Debris Rack or Grill

Grill, grid or post structure located near a culvert entrance to hold back floating debris too large to pass through the
culvert.

Deck
The part of a bridge that spans between abutments or pier supports, and carries the road traffic.

Design speed
The assessed maximum safe speed that can be maintained over a specified section of road when conditions are so
favourable that the design features of the road govern the speed.

Dispersive soil
Soil in which the clay particles detach from each other and from the soil structure in the presence of water and go into
suspension.

Distributor
A vehicle or towed apparatus comprising an insulated tank, usually with heating and circulating facilities, and a spray
bar capable of applying a thin, uniform and predetermined layer of binder. The equipment may also be fitted with a
hand lance for manual spraying.

Ditch (Drain)
A long narrow excavation designed or intended to collect and drain off surface water.

Drainage
Interception and removal of ground water and surface water by artificial or natural means.

Design Manual for Low Volume Rural Roads in Myanmar xii

Drainage Pipe
An underground pipe to carry water.

Dressed Stone
See Cobble Stone

Drift or Ford
A stream or river crossing at bed level over which the stream or river water can flow.

Dry-bound Macadam
A pavement layer constructed where the voids in a large single-sized stone skeleton are filled with a fine sand,
vibrated in with suitable compaction equipment.

Earth Road
See ENS.

Embankment
Constructed earthworks below the pavement raising the road above the surrounding natural ground level.

ENS (Engineered Natural Surface)

An earth road built from the soil in place at the road location, and provided with a camber and drainage system

Expansive soil
Typically clayey soil that undergoes large volume changes in direct response to moisture changes.

Filler
Mineral matter composed of particles smaller than 0.075mm.

Flow Spreader
A structure designed to disperse the flow at the outfall of a ditch or drain to minimise the risk of erosion downstream.

Fog Spray/Seal
A light application of diluted bitumen emulsion to the final layer of stone of a reseal or chip seal, or to an existing
bituminous surfacing as a rejuvenating maintenance treatment.

Ford
See Drift

Formation
The shaped surface of the earthworks, or subgrade, before constructing the pavement layers.

Gabion
Stone-filled wire or steel mesh cage. Gabions are often used as retaining walls or river bank/bed scour protection
structures.

Geocells
Typical cellular confinement systems are made with ultrasonically-welded high-density polyethylene (HDPE) or Novel
Polymeric Alloy strips that are expanded on-site to form a honeycomb-like structure which may be filled with sand,
soil, rock or concrete. Used in construction for erosion control, soil stabilisation on flat ground and steep slopes,
channel protection, and structural reinforcement for load support and earth retention.

Design Manual for Low Volume Rural Roads in Myanmar xiii

Gravel (Construction Material)
A naturally-occurring, weathered or naturally transported rock within a specific coarse particle size range. Gravel is
typically used as a pavement layer in its natural or modified condition, or as a road surface wearing course. Suitable
gravel may also be used in a graded gravel seal in appropriate circumstances.

Hand Packed Stone

A layer of large, angular broken stones laid by hand with smaller stones or gravel rammed into the spaces between
stones to form a road surface layer.

Incremental paving
Road surface comprising small blocks such as shaped stone (setts) or bricks, jointed with sand or mortar.

Intermediate Equipment
Simple or intermediate equipment, designed for low initial and operating costs, durability and ease of maintenance
and repair in the conditions typical of a limited-resource environment, rather than for high theoretical efficiency. It is
preferable if the equipment can also be manufactured or fabricated locally/regionally.

Invert
The lowest point of the internal cross-section of a ditch, pipe or culvert.

Labour Based Construction

Economically efficient employment of as great a proportion of labour as is technically feasible throughout the
construction process to produce the standard of construction as demanded by the specification and allowed by the
available funding

Labour Intensive Construction

Works using large numbers of labourers with the prime objective of creating temporary or permanent employment,
often with achieving sustainable and durable infrastructure as a secondary concern.

Layby
An area adjacent to the road for the temporary parking of vehicles.

Lime
Lime in a material derived from the burning of limestone or chalk. It is normally obtainable in its ‘hydrated’ form
(slaked) as Calcium Hydroxide. It can be used for the drying, improvement and stabilisation of suitable soils, as an anti-
stripping agent in the production of bituminous mixes and as a binder in masonry or brick work mortars.

Local Resources
These can be human resources, local government, private, NGO, and community institutions, local entrepreneurs such
as contractors, consultants, industrialists and artisans, local skills, locally made or fabricated intermediate equipment,
local materials such as local produced aggregates, bricks, timber and marginal materials, locally raised finance or
provision of materials or services in kind.

Local Resource Based Road Works aim to deliver the maximum benefits to local communities and development.

Low Volume Road

Roads carrying less than 300 motor vehicles per day and up to approximately 1 million equivalent standard axles over
their design life.

Macadam
A mixture of broken or crushed stone of various sizes (usually less than 3cm) laid to form a road surface layer. Bitumen
macadam uses a bituminous binder to hold the material together. Tarmacadam uses tar for the same purposes.
Bound macadams are usually expensive for use on LVR.

Design Manual for Low Volume Rural Roads in Myanmar xiv

Manhole
Accessible pit with a cover forming part of the drainage system and permitting inspection and maintenance of
underground drainage pipes.

Margins
The right of way or land area maintained or owned by the road authority or owner.

Mitre Drain (Turn Out Drain)

A drain that leads water away from the Side Drains to the adjoining land.

Otta Seal
A carpet of graded (natural gravel or crushed rock) aggregate spread over a freshly sprayed hot bituminous ‘soft’ (low
viscosity) binder and rolled in with heavy roller.

Outfall
Discharge end of a ditch or culvert.

Parapet
The protective edge, barrier, wall or railing at the edge of a bridge deck.

Pavé
See Sett

Paved Road
A paved road is a road with a Stone, Bituminous, Brick or Concrete surfacing.

Pavement
The constructed layers of the road on which vehicles travel.

Penetration Macadam
A pavement layer made from one or more applications of coarse, open-graded aggregate (crushed stone, slag, or
gravel) followed by the spray application of bituminous binder. Usually comprising two or three applications of stone
each of decreasing particle size, each grouted into the previous application before compaction of the completed layer.

Permeable Soils
Soils through which water will drain easily e.g. sandy soils. Clays are generally impermeable except when cracked or
fissured (e.g. ‘Black Cotton’ soil in dry weather).

Prime Coat
A coat of suitable bituminous binder applied to a non-bituminous granular pavement layer as a preliminary treatment
before the application of a bituminous base or surfacing. While adhesion between this layer and the bituminous base
or surfacing may be promoted, the primary function of the prime coat is to assist in sealing the surface voids and bind
the aggregate near the surface of the layer. Not to be confused with Tack Coat.

Reinforced Concrete
A mixture of coarse and fine stone aggregate bound with cement and water and reinforced with steel rods or mesh for
added strength.

Reseal
A surface treatment applied to an existing bituminous surface.

Design Manual for Low Volume Rural Roads in Myanmar xv

Rejuvenator
A material which may range from a soft bitumen to petroleum which, when applied to reclaimed asphalt or to existing
bituminous surfacing, has the ability to soften aged, hard, brittle binders.

Riprap
Stones, usually between 5 to 50 kg, used to protect the banks or bed of a river or watercourse from scour.

Roadbase and Sub-base

Pavement courses between surfacing and subgrade.

Road Maintenance
Suitable regular and occasional activities to keep pavement, shoulders, slopes, drainage facilities and all other
structures and property within the road margins as near as possible to their constructed or renewed condition.
Maintenance includes minor repairs and improvements to eliminate the cause of defects and avoid excessive
repetition of maintenance efforts.

Roadway
The portion within the road margins, including shoulders, for vehicular use.

Scarifying
The systematic disruption and loosening of the top of a road or layer surface by mechanical or other means.

Scour -Defect:
Erosion of a channel bed area by water in motion, producing a deepening or widening of the channel.

Scour Checks
Small checks in a ditch or drain to reduce water velocity and reduce the possibility of erosion.

Scuppers
Drainage pipes or outlets in a bridge deck.

Seal
A term frequently used instead of “reseal” or “surface treatment”. Also used in the context of “double seal”, and
“sand seal” where sand is used instead of stone.

Selected layers
Pavement layers of imported selected gravel or soil materials used to bring the subgrade support properties up to the
required structural standard for placing the sub-base or road base layer.

Sett (Pavé)
A small piece of hard stone trimmed by hand to a size of about 10cm cube used as a paving unit.

Shoulder
Paved or unpaved part of the roadway next to the outer edge of the pavement. The shoulder provides side support for
the pavement and allows vehicles to stop or pass in an emergency.

Site Investigation
Collection of essential information on the soil and rock characteristics, topography, land use, natural environment,
and socio-political environment necessary for the location, design and construction of a road.

Slope
A natural or artificially constructed soil surface at an angle to the horizontal.

Design Manual for Low Volume Rural Roads in Myanmar xvi

Slurry
A mix of suitably graded fine aggregate, cement or hydrated lime, bitumen emulsion and water, used for filling the
voids in the final layer of stone of a new surface treatment or as a maintenance treatment (also referred to as a slurry
seal).

Slurrybound Macadam
A surfacing or pavement layer constructed where the voids in single-sized stone skeleton are filled using bituminous
slurry.

Sods
Turf but with more soil attached (usually more than 10 cms soil thickness).

Soffit
The highest point in the internal cross-section of a culvert, or the underside of a bridge deck.

Spray Lance
Apparatus permitting hand-application of bituminous binder at a desired rate of spread through a nozzle.

Squeegee
A small wooden or metal board with a handle for spreading bituminous mixtures by hand.

Stringer
Longitudinal beam in a bridge deck or structure.

Sub-base
See Roadbase.

Subgrade
The native material or earthworks formation underneath a constructed road pavement.

Sub-Soil Drainage
See Underdrainage.

Surface Dressing
A sprayed or hand applied film of bitumen followed by the application of a layer of stone chippings, which is then
lightly rolled.

Surface Treatment
A general term incorporating chip seals, slurry seals, micro surfacing, or fog sprays.

Surfacing
The road layer with which traffic tyres make direct contact. Consists of wearing course, and sometimes a base course
or binder course.

Tack Coat
A coat of bituminous binder applied to a primed layer or to an existing bituminous surface as a preliminary treatment
to promote adhesion between the existing surface and a subsequently applied bituminous layer.

Tar Binder
A binder made from processing coal.

Template
A thin board or timber pattern used to check the shape of an excavation.

Design Manual for Low Volume Rural Roads in Myanmar xvii

Traffic Lane
The portion of the carriageway usually defined by road markings for the movement of a single line of vehicles.

Transverse Joint
Joint normal to, or at an angle to, the road centre line.

Turf
A grass turf is formed by excavating an area of live grass and lifting the grass complete with about 5 cm of topsoil and
roots still attached.

Turn Out Drain

See Mitre Drain.

Underdrainage (Sub-Soil Drainage)

System of pervious pipes or free draining material, designed to collect and carry water in the ground.

Unpaved Road
A road with a soil or gravel surface.

Vented Drift
See Causeway.

Waterbound Macadam
A pavement layer constructed where the voids in a large single-sized stone skeleton are filled with a fine sand, washed
in by the application of water.

Wearing Course
The upper layer of a road pavement on which the traffic runs and is expected to wear under the action of traffic. This
applies to gravel and bituminous surfaces.

Weephole
Opening provided in retaining walls or bridge abutments to permit drainage of water in the filter layer or soil layer
behind the structure. Weepholes prevent water pressure building up behind the structure.

Windrow
A ridge of material formed by the spillage from the end of the machine blade or continuous heap of material formed
by labour.

Wingwall
Retaining wall at a bridge abutment to retain and protect the embankment fills behind the abutment.

Design Manual for Low Volume Rural Roads in Myanmar xviii