SEMINAR FLEXIBLE PAVEMENT DESIGN
Transcript of 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
CROSS SECTION OF FLEXIBLE PAVEMENT
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
CROSS SECTION OF FLEXIBLE PAVEMENT
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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
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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
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≥
≥
≥
≥
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
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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
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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:
FOR INTERNAL USE ONLY
Base course
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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
FOR INTERNAL USE ONLY
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
CRACK
SURFACE DEFORMATION
SURFACE DEFECT
PATCH AND POTHOLE
TERIMA KASIH