seminar flexible pavement design

SEMINAR ON FLEXIBLE

PAVEMENT DESIGN

ROAD ENGINEERING

GEOMETRIC DESIGN

PAVEMENT

GEOTECHNICAL

DRAINAGE

ROAD SAFETY

OTHERS (ROAD FURNITURE, SERVICES, TRAFFIC LIGHTS, ETC)

GEOTECHNICAL CONSIDERATIONS

Is the road on cut ground?

Is the underground water table higher than the pavement?

Is it on fill ground?

What type of underlying soil?

Any compressible layer?

Need geotechnical treatment?

CUT AND FILL SECTION

GEOTECHNICAL

Ground Treatment

Soil Replacement

Combination Of

These/Other Methods

Pile Embankment

PAVEMENT

Pavement is a structure consisting of superimposed layers of processed materials above the sub-grade, whose primary function is to distribute the applied vehicle loads to the sub-grade.

CROSS SECTION OF FLEXIBLE PAVEMENT

PAVEMENT

The pavement structure should be able to provide a surface of acceptable riding quality and adequate skid resistance

PAVEMENT

The ultimate aim is to ensure that the transmitted stresses due to wheel loads are sufficiently reduced, so that they will not exceed bearing capacity of the sub-grade.

LOAD AND STRESS DISTRIBUTION

PAVEMENT

Two types of pavements are generally recognized as serving this purpose, namely flexible pavements and rigid pavements.

TYPES OF PAVEMENTS

FLEXIBLE PAVEMENT RIGID PAVEMENT

FLEXIBLE VERSUS RIGID PAVEMENTS

FLEXIBLE RIGID

Transfer load to subgrade via the granular

particles of the upper layers

Transfer load to the subgrade via the slab

Initial construction cost is lower than rigid

pavement

Initial construction cost is higher

Maintenance cost is higher than rigid

pavement

Maintenance cost is lower because it seldom

needs maintenace

Life span is shorter than rigid pavement Life span is longer

Easier to maintain than rigid pavement – can

be opened to traffic after repair works

Difficult to maintain – have to allow time for

concrete to gain strength before re-opening

Easier to lay underground utilities Difficult to lay underground utilities

Arahan Teknik(Jalan) 5/85

Cawangan Jalan, Ibu Pejabat JKR, K.L

FOR INTERNAL USE ONLY

2.2 Definition and Function of Each Layer

2.2.1 Subgrade

The uppermost part of the soil, natural or imported, supporting the load transmitted

from the overlying layers.

2.2.2 Subbase Course

The layer(s) of the specified material built up to the required designed thickness

immediately overlaying the subgrade. It serves as an aid to disperse the load from

the base course before transmitting it to the subgrade. (This layer may be absent in

some designs.)

2.2.3 Base Course

The layer(s) of specified material built up to the required designed thickness

normally overlying the subbase course. This layer plays a prominent role in the

support and dispersion of the traffic loads.

2.2.4 Surface Course

All the bound layer(s) within the pavement i.e. wearing course, intermediate course

and binder course are. embodied under this general terminology. This layer(s) forms

an impermeable and flexible lining of high elastic modulus.

2.2.5 Binder Course

The bound layer(s) overlying the base course. Apart from supporting and dispersing

the traffic load, it also resists shear.

2.2.6 Wearing Course

The topmost layer of the surface course. It is in direct contact with the traffic and

consequently, it must resist abrasion and prevent skidding.

FLEXIBLE PAVEMENT

DESIGN

How to design flexible pavement?

FLEXIBLE PAVEMENT

DESIGN

Arahan Teknik (Jalan) 5/85

Arahan Teknik (Jalan) 5/85

(Pindaan 2013)

ArahanTeknik

(Jalan) 5/85

Initial annual commercial

traffic

•ADT = Average Daily Traffic

•Pc = Percentage of Commercial Vehicle

•Vo = ADT x 0.5 x 365 x Pc/100

Total number of commercial

vehicles

•Vc =Total number of commercial vehicle for x years

•Vo = Initial yearly commercial traffic

•r = rate of annual traffic growth

• 𝑽𝒄 =𝑽𝟎 (𝟏+𝒓)

𝒙−𝟏

𝒓

Total Equivalent Standard

Axles

•ESA = Vc x e

•*Note : for highway with three or more lanes per direction, the value on traffic estimation shall be based on 80% of ADT

•For e value, refer to Table 3.1

Subgrade California

Bearing Ratio (CBR)

• CBR shall be taken as that of the underlying layer within 1m below subgrade surface

• For varying CBR within the 1m depth of subgrade, the mean CBR is determined

• 𝑪𝑩𝑹 =𝒉𝟏𝑪𝑩𝑹𝟏

Τ𝟏 𝟑+𝒉𝟐𝑪𝑩𝑹𝟐

Τ𝟏 𝟑+⋯+𝒉𝒏𝑪𝑩𝑹𝒏

Τ𝟏 𝟑

𝟏𝟎𝟎

𝟑

Design Thickness

•From Nomograph, get the 𝑻𝑨•From 𝑻𝑨, get the thickness of various

layers

• 𝑻𝑨 = 𝒂𝟏𝑫𝟏 + 𝒂𝟐𝑫𝟐 +⋯+ 𝒂𝒏𝑫𝒏

Equivalence Factor

Table. 3.1 Guide for Equivalence Factor

Local

1.23.7

0-15%

Trunk

2.0

16-50%

3.0

51-100&Percentage of selected

heavy goods vehicles*

Type of road Equivalence

Factor

Table. 3.1 Guide for Equivalence Factor

≥

≥

≥

≥

DESIGN EXAMPLE

≥

≥

≥

≥

SPECIFICATION

Material

Machinery

Method of Construction

Sub-grade

(JKR/SPJ/2013-S2)

S2-13

limited to 400 mm unless trial compaction shows compliance with

larger loose thickness and with the approval from the S.O. The

Contractor shall carry out field compaction trials, supplemented by

any necessary laboratory investigations, as required by the S.O.

This shall be done by using the procedures proposed by the

Contractor for earthworks and shall demonstrate to the S.O. that all

the specified requirements regarding compaction can be achieved.

Compaction trials with the main types of material likely to be

encountered shall be completed before the works with the

corresponding materials will be allowed to commence. Each trial

area shall be not smaller than 8 m x 15 m.

For earthwork compaction of less than 100 cubic meters, trial

compaction can be waived with approval from the S.O., but field

density testing as per Sub-Section 2.2.4.4 (d) is still remained

necessary as and when instructed by the S.O.

c) Degree of Compaction

The whole of the embankment below the top 300 mm of the

subgrade shall be compacted to not less than 90% (for cohesive

material) or 95% (for cohesion less material) of the maximum dry

density determined in the latest MS 1056 Compaction Test (4.5 kg-

rammer method), unless otherwise specified in the Drawings.

d) Field Density Testing

Field density tests on each layer of compacted earth fill shall be

carried out using the sand replacement method in accordance with

the latest MS 1056 or by using other means of testing of

comparable accuracy approved by the S.O.

e) Moisture Control

Each layer of earth fill shall be processed as necessary to bring its

moisture content to a uniform level throughout the material, suitable

for compaction. The optimum moisture content as determined by

the latest MS 1056 Compaction Test (4.5 kg rammer method) shall

be used as a guide in determining the proper range of moisture

content, preferably on the wet side, at which each soil type shall be

compacted. Water shall be added in fine spray for consistent

moisture absorption in the fill, or the material aerated and dried to

adjust the soil to the proper range of moisture content to obtain the

required density. A satisfactory method and sufficient equipment as

approved by the S.O. shall be used for the furnishing and handling

of water.

If the natural water content of suitable material is too high for the

proper compaction to be carried out, the Contractor can either bring

Sub-base

Page 18




4.0 SUBBASE COURSE

4.1 General Sand gravel and laterite are amongst the various types of subbase course

materials. When these materials do not have the required quality, cement stabilisation of

these material or crushed aggregate is to be used.

From an economic point of view, locally available materials such as sand, gravel,

laterite, etc. should be utilised for subbase course materials.

4.2 Material Requirements

The quality of materials shall conform to the following standards and shall not include a

deleterious amount of organic materials, soft particles, clay lumps etc.

4.2.1 Locally available materials, such as sand, gravel, soft rocks, laterite etc should be

utilised for subbase course materials, from an economic point of view. When these

materials do not meet the required standard, stablisation with cement should be

considered. When a suitable and economic natural material is not available crushed

aggregates (crusher run) are commonly used.

4.2.2 The quality of materials shall conform to the following standards and not include a

deleterious amount of organic materials, soft particles, clay lumps etc.

Table 4.1 Standard Properties of Subbase

Note* :- 1. Sieve ;analysis should be done according to BS 1377:75

2. For sand, laterite etc. nominal size shall not be greater than 1/3 of the

compacted layer thickness

Quality Test Method Crushed Sand

Aggregate Laterite etc

CBR (X) BS 1377:75 Not less Not less

than 30 than 20

Plasticity BS 1377:75 Not greater Not greater

Index (P.I) than 6 than 6

Los Angeles

Abrasion ASTM C 131 Not greater

loss (%) than 50

Cement

Stabilised BS 1377:75 - Not less

CBR (%) than 60

Base course

Page 19



4.2.3 Natural materials vary from place to place throughout the country. Generally, natural

sand and laterite give a strength of CBR 20% or more. However, the strength of

some materials may be lower in certain regions. These materials can be stabilised

with cement. A CBR of not less than 30% for crushed aggregates can normally be

obtained from the quarries.

4.2.4 A cement content of 2% to 4% by weight is recommended for stabilisation with

cement. Higher cement content will usually produce a stiff mix which consequently

would fail due to stress concentration.

4.2.5 For maximum utilisation of suitable local materials, no gradation is specified.

Gradation is required only for crushed aggregates to avoid seggregation and to

obtain better workability for construction.

For construction purposes, the nominal size of local material is specified.

4.2.6 A sand layer of 10 cm thick is required to be placed on top of the subbase course,

extending from edge to edge of the formation width.

5.0 BASE COURSE

5.1 General

Base course shall be selected materials such as crushed stones and sand, or a

combination of these materials. It may be stabilised with cement, bitumen or lime.

In the AASHO road test results, it was found that stabilised base courses especially

bituminous stabilised base gave the best performance with respect to strength and

durability. Therefore bituminous treated base course are recommended to be used

whenever suitable.

Three types of base courses are specified here. They are crushed aggregates, cement

stabilised and bitumen stabilised base courses.

5.2 Requirements for materials and mixtures

The quality of both materials and mixtures shall conform to the following requirements:


Base course

Page 20



Table 5.1 Material Properties of Base Course

Table 5.2 Gradation for Base Course

Note: Sieve analysis shall be done according to BS 1377:75


Quality Test Crushed Cement Bitumen Stabilised

Method Aggregates Stabilised Type 1 Type II

CBR (%) BS 1377:75 Not less - - -

than 80

Plasticity BS 1377:75 Not Not Not Not

Index greater greater greater greater

than 4 than 8 than 6 than 8

L.A ASTM Not Not Not Not

Abrasion C131 greater greater greater greater

Loss (%) than 40 than 40 than 40 than 40

Water Not Not

Absorption M.S. 30 - - greater greater

(%) than 4 than 4

Sieve Percentage by weight

size passing

(mm) Crushed Cement Bitumen stabilised

stabilisation

aggregates

Type I Type II

40 L00 Nominal 100 Nominal

size of size of

25 70-100 material 70-100 material

used shall used shall

10 40-65 not be 40-65 not be

greater greater

5 30-55 than 1/3 of 30-55 than 1/3 of

compacted compacted

2.4 20-45 layer thick ness 20-45 layer thick ness

0.420 10-25 10-25

0.075 2-10 2-10

Bituminous Prime and Tack Coats

Bituminous Coat

Prime Coat Tack Coat

Prime Coat Specification

Tack Coat Specification

• Bituminous tack coat material shall be rapid-setting cationic bitumen emulsion of grade RS-1K conforming to the requirements of MS 161.

Asphaltic Concrete Materials

Asphaltic Concrete

Coarse aggregate

Fine aggregate

Filler

Bitumen

Asphaltic Concrete

Coarse Aggregate

Coarse aggregate shall be screened crushed rock, angular in shape and free from dust, clay, vegetative and other organic matter

Asphaltic Concrete

Fine Aggregate

Fine aggregate shall be clean screened quarry dust. Other types of fine aggregate may be used subject to the approval of the S.O.

Fine aggregate shall be non-plastic and free from clay, loam, aggregation of material, vegetative and other organic matter,

Specification of Material

Specification Coarse

Aggregates

Los Angeles abrasion (ASTM

C131)

< 25%

Soundness test (AASHTO T104) <18%

The Flakiness (MS 30) <25%

Water Absorption (MS 30) <2%

Polished stone value (MS 30) >40%

(Wearing Course)

Specification Fine Aggregates

Aggregate Passing the 4.75mm

sieve (ASTM D2419)

> 45%

Soundness test (AASHTO T104) <20%

The Fine aggregate angularity

(ASTM C1252)

>45%

Water Absorption (MS 30) <2%

The Methylene Blue (Ohio

Department of Transportation

Standard Test Method)

<10 mg/g

Mineral Filler

Mineral filler shall be incorporated as part of the combined aggregate gradation. It shall be of finely divided mineral matter of hydrated lime (calcium hydroxide).

The hydrated lime shall be sufficiently dry to flow freely and shall be essentially free from agglomerations

Not less than 70% by weight shall pass the BS 75 um sieve

Mineral Filler

The ratio of the combined coarse aggregate, fine aggregate and mineral filler of the final gradation passing 75 um sieve to bitumen, by weight, shall be in the range of 0.6 to 1.2.

As a guide, the total amount of hydrated lime shall be approximately 2% by weight of the combined aggregates

Bituminous Materials

• Bituminous binder for asphaltic concrete shall be bitumen of penetration grade 60-70 or 80-100 which conforms to MS 124

Equipment

Asphalt Mixing Plant

Tip-Truck

Road Cleaning

Equipment

Asphalt Paver

Rollers

Pneumatic Tyred Roller Steel Wheeled

Tandem Roller

Equipment

Pressure Distributor

for Bituminous

Material

Storage and Heating

Facilities for Bituminous Prime Coat

Mechanical Power Broom

Construction method for Asphaltic Concrete

Surface Preparation and Cleaning• The surface to be covered

shall have been prepared in accordance with the appropriate Sections of this Specification.

Aggregate Handling and Heating• Each aggregate to be used

in the asphaltic concrete mixes shall be stored in a separate stockpile near the mixing plant.

sand and other fine aggregates shall be kept dry using waterproof covers

The aggregates shall be fed into the dryer at a uniform rate proportioned

The aggregates shall be dried and heated so that when delivered to the mixer they shall be at a temperature in the range 150 C˚ to 170 C˚.

the aggregates shall be screened into four (or more)

• fractions which shall be separately stored in the hot aggregate storage bins in

Heating of Bitumen•The bitumen shall be heated so that when delivered to the mixer it shall be at a temperature in the range 140 C˚ to 160 C˚.

Mixing Asphaltic Concrete•The mixing plant shall be so coordinated and operated as to consistently produce asphaltic concrete mixes

Transportation of Asphaltic Concrete•Asphaltic concrete shall be transported from the mixing plant to the site of the paving works in loads of not less than 5 tonnes using tip-trucks

Care shall be taken in the truck loading, hauling and unloading operations to prevent segregation of the mix.

The asphaltic concrete shall be protected from contamination by water, dust, dirt and other deleterious materials during transportation

The temperature of asphaltic concrete immediately before unloading from the truck either into the paver hopper or on to the road for hand spreading shall be not less than 130 C˚ (increased by 10 C˚ for penetration grade 60-70 bitumen).

• Asphaltic concrete shall not be opened to traffic until compaction has been completed and the material has thoroughly cooled and set in the opinion of the S.O.

• Vehicles may be allowed to run on the work after rolling has been completed, provided that speeds are restricted to 30 km/h or less and sharp turning movements are prohibited.

Opening to Traffic

• Asphaltic concrete binder and wearing courses shall be finished in a neat and workmanlike manner

Finished Asphaltic Concrete

•Asphaltic concrete, compaction by rolling shall commence as soon after laying

•The temperature of asphaltic concrete at the commencement of rolling shall be not less than 120 C˚ (increased by 10 C˚ for penetration grade 60-70 bitumen).

•Rolling shall not be continued when the temperature of asphaltic concrete has decreased to 80 C˚ or lower.

•the pneumatic tyred roller shall be ballasted to an operating weight of not less than 15 tonnes and its tyreinflation pressure shall be not less than 0.7 N/mm2.

•The steel wheeled rollers shall operate at speeds of not more than 5 km/h and the pneumatic tyredrollers shall operate at speeds of not more than 8 km/h.

•No roller or heavy vehicle shall be allowed to stand on newly laid bituminous mix before compaction has been completed

Compaction of Asphaltic Concrete.

•Generally, each paving layer shall have a compacted thickness of not less than twice the nominal maximum aggregate size of the mixture, and not more than 100 mm.

• laying shall be carried out using a paver approved by the S.O.

• initial rolling the temperature of asphaltic concrete shall be not less than 120 C˚ (increased by 10 C˚ for penetration grade 60-70 bitumen).

•Material which has cooled below the specified temperature before laying shall not be used and shall be removed from the Site of the Works.

•Care shall be taken that no bituminous mix is placed on expansion joints at bridges,

• inspection covers for utilities ducts, drainage and sewerage manholes

Laying Asphaltic Concrete

CONSTRUCTION

DESIGN MIX

TRIAL MIX

TRIAL LAY

SUPERVISION

Follow the specifications

1

Carry out the testing and inspection

2

Follow the approved methods of construction

3

Check the materials

4

Ensure workers are skilled

5

Check conditions of the machinery/equipment

6

Check the temperature of the asphaltic mix

7

Any other factors

8

MAINTENANCE

THE PAVEMENT PERFORMANCE

VISUAL ASSESSMENT OF SUFACE

CONDITIONS

Crack

Surface Deformation

Surface Defect

Patch

Pothole

Edge Defect

SURFACE DEFORMATION

SURFACE DEFECT

PATCH AND POTHOLE

TERIMA KASIH

seminar flexible pavement design

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