iii. The mean optimum bitumen content shall be determined by averaging five optimum
bitumen contents so determined as follows;
a) Peak of curve taken from the stability graph
b) Flow equals to 3 mm from the flow graph
c) Peak of curve taken from the bulk specific gravity graph
d) VFB equals to 75% for wearing course and 70% for binder course from the VFB graph
e) VIM equals to 4.0% for wearing course and 5.0% for binder course from the VIM graph.
Specification Parameter for AC JKR/SPJ/2008-S4
• The mixture shall be designed in accordance to the Standard Marshall Test Method.
• It shall conform to the following requirements :
Table 3-6 : Test and analysis parameters
Source : Jabatan Kerja Raya, STANDARD SPECIFICATION FOR ROADWORKS, JKR/SPJ/2008-S4,
2008 (page 28)
Parameter Wearing Course Binder Course
Stability (S) > 8000 N > 8000 N
Flow (F) 2.0 – 4.0 mm 2.0 – 4.0 mm
Stiffness (S/F) > 2000 N/mm > 2000 N/mm
Air Voids in Total Mix (VIM) 3.0 – 5.0 % 3.0 – 7.0 %
Voids Filled with Bitumen (VFB) 70 – 80 % 65 – 75 %
• If all the value comply with the table, the mixture with the mean optimum bitumen content
shall be used in plant trials
• If any values does not comply with table, the mix design procedure shall be repeated using
different laboratory design mix aggregate gradation until all the design parameters are
satisfied
3.2.2 Calculate the optimum bitumen content
Determination of optimum asphalt content using the test results pertaining to a Marshall trial mix
with different asphalt contents (i.e. evaluation of a trial mix), is illustrated in the following
Example:
Following are the test results pertaining to a Marshall Trial mix with different bitumen contents:
Table 3-7: Test Result
Air voids In
Bitumen content Density Stability Flow Total Mix VFB VMA
3
(%) (kg/m ) (kN) (mm) (%) (%)
(%)
4.5 2325 9.8 2.6 6.0 63.0 16.5
5.0 2380 9.9 3.1 4.0 75.0 16.0
5.5 2380 8.6 3.5 3.5 79.0 17.0
6.0 2345 7.6 3.7 3.0 83.0 18.0
6.5 2320 6.2 4.6 2.5 85.0 19.0
Plot the test results and find the optimum bitumen content to meet suggested requirements for a
surface course (12.5 mm or ½ inch aggregate) for a medium-traffic area.
46
i. Plot the Bitumen Content vs. density, stability, flow, %VIM, %VFB, and %VMA
ii. Using the plotted graphs, determine the bitumen contents corresponding to maximum
density, maximum stability, and 4% air voids (the middle of the 3 – 5% allowed)
47
The mean optimum bitumen content shall be determined by averaging five optimum bitumen
contents so determined as follows;
i. Peak of curve taken from the stability graph, % Bitumen Content = 4.90 %
ii. Flow equals to 3 mm from the flow graph, % Bitumen Content = 5.00 %
iii. Peak of curve taken from the bulk specific gravity graph, % Bitumen Content = 5.25 %
iv. VFB equals to 75% for wearing course and 70% for binder course from the VFB graph, %
Bitumen Content = 5.25 %
v. VIM equals to 4.0% for wearing course and 5.0% for binder course from the VIM graph, %
Bitumen Content = 5.25 %
Check
Table 3-8: Data comparison with JKR STANDARD SPECIFICATION FOR ROADWORKS
Specification
Parameter Result Remarks
(Binder Course, JKR 1988)
Stability 10 kN / 1000kg > 450 kg OK
Flow 3 mm > 2.0 mm OK
Stiffness - > 225 kg/mm -
VTM 4 % 3.0 – 7.0 % OK
VFB 75 % 65 – 80 % OK
EXERCISE 3
a. Determine the optimum bitumen content for the ACB 28 mix given below.
48
b. Complete the Marshall form below and determine the optimum bitumen content of the mix design
Stability Flow
Weight (g) Specific Gravity Volume Voids (%) Stiffness
% Bulk (kN) (mm)
Bitumen Volume Refer
Spec. Saturated 3 Bulk Max. Mineral Filled Total Table CORR
Sample. No Surface Air Water (cm ) (Density) Theory Bitumen Aggregate Voids Agg. Bitumen Mix CORR MEAS (Stability)
No Dry (%VMA) (%VFB) (%VIM) Factor
F G H I J K L M N O P Q R S
B C D E B X G (100-B)G 100-I- 100- CORR
(C-E) D/F * 100-J 100(I/L) P X O Q/R
SG BIT SG AG J (100G/H) FACTOR
4.5 1200.8 1195.3 685.9 1161 3.27
1196.4 1193.7 685.9 1100 3.17
1195.7 1192.7 685.4 1150 3.26
AVG 3.2
5.00 1197.9 1194.7 690.7 1191 3.70
1195.8 1192.7 690.2 1163 3.71
1200.5 1197.1 692.4 1151 3.83
AVG 3.7
5.50 1202.8 1199.9 695.2 1321 4.30
1180.3 1176.4 682.7 1298 4.29
1178.6 1174.8 681.2 1239 3.93
AVG 4.2
6.00 1185.0 1182.3 685.8 1163 4.63
1196.0 1191.5 690.6 1135 4.72
1188.8 1184.0 685.6 1111 4.69
AVG 4.7
6.50 1172.7 1168.2 675.9 870 5.31
1185.6 1180.8 685.6 870 5.48
1178.9 1172.4 679.6 919 5.69
AVG 5.5
REMARKS
* Calculation for Max. Theoretical Specific gravity (Column H) = 100 / [ ( % By Weight of Bitumen / SG BIT ) + ( % By Weight of Combined Aggregate / SG AG ) ]
SG BIT = 1.02 Mixing Temperature = 145°C to 155°C
SG AG = 2.668 Compacting Temperature = 135°C
Pen. Grade Bitumen = 80/100 PEN Test Temperature = 60°C for 45 minutes
Density Asphalt Mixture = Bulk S.G x 1000 kg/cu.m Density Asphalt Mixture = Bulk S.G x 1000 kg/cu.m
Mixing Temperature = 145°C to 155°C
SG AG = 2.668 Compacting Temperature = 135°C
Pen. Grade Bitumen = 80/100 PEN Test Temperature = 60°C for 45 minutes
49 % By Weight of Combined Aggregate = 100 - B
b. Complete the Marshall form below and determine the optimum bitumen content of the mix design
Stability Flow
Weight (g) Specific Gravity Volume Voids (%) Stiffness
% Bulk (kN) (mm)
Bitumen Volume Refer
Spec. Saturated 3 Bulk Max. Mineral Filled Total Table CORR
Sample. No Surface Air Water (cm ) (Density) Theory Bitumen Aggregate Voids Agg. Bitumen Mix CORR MEAS (Stability)
No Dry (%VMA) (%VFB) (%VIM) Factor
F G H I J K L M N O P Q R S
B C D E B X G (100-B)G 100-I- 100- CORR
(C-E) D/F * 100-J 100(I/L) P X O Q/R
SG BIT SG AG J (100G/H) FACTOR
4.5 1200.8 1195.3 685.9 1161 3.27
1196.4 1193.7 685.9 1100 3.17
1195.7 1192.7 685.4 1150 3.26
AVG 3.2
5.00 1197.9 1194.7 690.7 1191 3.70
1195.8 1192.7 690.2 1163 3.71
1200.5 1197.1 692.4 1151 3.83
AVG 3.7
5.50 1202.8 1199.9 695.2 1321 4.30
1180.3 1176.4 682.7 1298 4.29
1178.6 1174.8 681.2 1239 3.93
AVG 4.2
6.00 1185.0 1182.3 685.8 1163 4.63
1196.0 1191.5 690.6 1135 4.72
1188.8 1184.0 685.6 1111 4.69
AVG 4.7
6.50 1172.7 1168.2 675.9 870 5.31
1185.6 1180.8 685.6 870 5.48
1178.9 1172.4 679.6 919 5.69
AVG 5.5
REMARKS
* Calculation for Max. Theoretical Specific gravity (Column H) = 100 / [ ( % By Weight of Bitumen / SG BIT ) + ( % By Weight of Combined Aggregate / SG AG ) ]
SG BIT = 1.02 Mixing Temperature = 145°C to 155°C
SG AG = 2.668 Compacting Temperature = 135°C
Pen. Grade Bitumen = 80/100 PEN Test Temperature = 60°C for 45 minutes
Density Asphalt Mixture = Bulk S.G x 1000 kg/cu.m Density Asphalt Mixture = Bulk S.G x 1000 kg/cu.m
Mixing Temperature = 145°C to 155°C
SG AG = 2.668 Compacting Temperature = 135°C
Pen. Grade Bitumen = 80/100 PEN Test Temperature = 60°C for 45 minutes
49 % By Weight of Combined Aggregate = 100 - B
Table 3-9. Stability correlation ratio (from ASTM D1559)
Approximate thickness of
Volume of specimen specimen Correlation Ratio
3
(cm )
(mm)
200 – 213 25.4 5.56
214 – 225 27.0 5.00
226 – 237 28.6 4.55
238 – 250 30.2 4.17
251 – 264 31.8 3.85
265 – 276 33.3 3.57
277 – 289 34.9 3.33
290 - 301 36.5 3.03
302 – 316 38.1 2.78
317 – 328 39.7 2.50
329 – 340 41.3 2.27
341 – 353 42.9 2.08
354 – 367 44.4 1.92
368 – 379 46.0 1.79
380 – 392 47.6 1.67
393 – 405 49.2 1.56
406 – 420 50.8 1.47
421 – 431 52.4 1.39
432 – 443 54.0 1.32
444 – 456 55.6 1.25
457 – 470 57.2 1.19
471 – 482 58.7 1.14
483 – 495 60.3 1.09
496 – 508 61.9 1.04
509 – 522 63.5 1.00
523 – 535 65.1 0.96
536 – 546 66.7 0.93
547 – 559 68.3 0.89
560 – 573 69.8 0.86
574 – 585 71.4 0.83
586 – 598 73.0 0.81
599 – 610 74.6 0.78
611 – 625 76.2 0.76
50
FEEDBACK ON EXERCISE 3
a. Determine the optimum bitumen content for the ACB 28 mix given below.
The OBC = 5.00 + 5.10 + 5.00 + 5.30 + 4.50
5
= 4.98 %
51
FEEDBACK ON EXERCISE 3
b. Complete the Marshall form below and determine the optimum bitumen content of the mix design
Stability Flow
Weight (g) Specific Gravity Volume Voids (%) Stiffness
% Bulk (kN) (mm)
Bitumen Refer
Spec. Saturated Volume Bulk Max. Mineral Filled Total Table CORR
3
Sample. No Surface Air Water (cm ) (Density) Theory Bitumen Aggregate Voids Agg. Bitumen Mix CORR MEAS (Stability)
No Dry (%VMA) (%VFB) (%VIM) Factor
F G H I J K L M N O P Q R S
B C D E B X G (100-B)G 100-I- 100- CORR
(C-E) D/F * 100-J 100(I/L) P X O Q/R
SG BIT SG AGG J (100G/H) FACTOR
4.5 1200.8 1195.3 685.9 514.9 2.321 2.490 10.1 83.1 6.8 16.9 60.0 6.8 1.00 1161 1161 3.27 355.0
1196.4 1193.7 685.9 510.5 2.338 2.668 10.2 83.7 6.1 16.3 62.7 12.4 1.00 1100 1100 3.17 347.0
1195.7 1192.7 685.4 510.3 2.337 2.668 10.2 83.7 6.1 16.3 62.5 12.4 1.00 1150 1150 3.26 352.8
AVG 2.3 2.6 10.2 83.5 6.3 16.5 61.7 10.5 1.0 1137.0 3.2 351.6
5.00 1197.9 1194.7 690.7 507.2 2.355 2.471 11.4 83.9 4.7 16.1 70.9 4.7 1.04 1191 1238.64 3.70 334.8
1195.8 1192.7 690.2 505.6 2.359 2.668 11.5 84.0 4.6 16.0 71.6 11.6 1.04 1163 1209.52 3.71 326.0
1200.5 1197.1 692.4 508.1 2.356 2.668 11.4 83.9 4.7 16.1 71.0 11.7 1.04 1151 1197.04 3.83 312.5
AVG 2.4 2.6 11.4 83.9 4.6 16.1 71.2 9.3 1.0 1215.1 3.7 324.4
5.50 1202.8 1199.9 695.2 507.6 2.364 2.453 12.6 83.7 3.6 16.3 77.6 3.6 1.04 1321 1373.84 4.30 319.5
1180.3 1176.4 682.7 497.6 2.364 2.668 12.6 83.7 3.6 16.3 77.6 11.4 1.09 1298 1414.82 4.29 329.8
1178.6 1174.8 681.2 497.4 2.362 2.668 12.6 83.7 3.7 16.3 77.2 11.5 1.09 1239 1350.51 3.93 343.6
AVG 2.4 2.6 12.6 83.7 3.7 16.3 77.5 8.8 1.1 1379.7 4.2 331.0
6.00 1185.0 1182.3 685.8 499.2 2.368 2.436 13.8 83.4 2.8 16.6 83.3 2.8 1.04 1163 1209.52 4.63 261.2
1196.0 1191.5 690.6 505.4 2.358 2.668 13.7 83.1 3.2 16.9 81.1 11.6 1.04 1135 1180.4 4.72 250.1
1188.8 1184.0 685.6 503.2 2.353 2.668 13.7 82.9 3.4 17.1 80.2 11.8 1.04 1111 1155.44 4.69 246.4
AVG 2.4 2.6 13.7 83.1 3.1 16.9 81.5 8.7 1.0 1181.8 4.7 252.6
6.50 1172.7 1168.2 675.9 496.8 2.351 2.418 14.8 82.4 2.8 17.6 84.3 2.8 1.04 870 904.8 5.31 170.4
1185.6 1180.8 685.6 500 2.362 2.668 14.9 82.8 2.3 17.2 86.5 11.5 1.04 870 904.8 5.48 165.1
1178.9 1172.4 679.6 499.3 2.348 2.668 14.8 82.3 2.9 17.7 83.7 12.0 1.04 919 955.76 5.69 168.0
AVG 2.4 2.6 14.9 82.5 2.7 17.5 84.8 8.7 1.0 921.8 5.5 167.8
52
FEEDBACK ON EXERCISE 3
b. Complete the Marshall form below and determine the optimum bitumen content of the mix design
Stability Flow
Weight (g) Specific Gravity Volume Voids (%) Stiffness
% Bulk (kN) (mm)
Bitumen Refer
Spec. Saturated Volume Bulk Max. Mineral Filled Total Table CORR
3
Sample. No Surface Air Water (cm ) (Density) Theory Bitumen Aggregate Voids Agg. Bitumen Mix CORR MEAS (Stability)
No Dry (%VMA) (%VFB) (%VIM) Factor
F G H I J K L M N O P Q R S
B C D E B X G (100-B)G 100-I- 100- CORR
(C-E) D/F * 100-J 100(I/L) P X O Q/R
SG BIT SG AGG J (100G/H) FACTOR
4.5 1200.8 1195.3 685.9 514.9 2.321 2.490 10.1 83.1 6.8 16.9 60.0 6.8 1.00 1161 1161 3.27 355.0
1196.4 1193.7 685.9 510.5 2.338 2.668 10.2 83.7 6.1 16.3 62.7 12.4 1.00 1100 1100 3.17 347.0
1195.7 1192.7 685.4 510.3 2.337 2.668 10.2 83.7 6.1 16.3 62.5 12.4 1.00 1150 1150 3.26 352.8
AVG 2.3 2.6 10.2 83.5 6.3 16.5 61.7 10.5 1.0 1137.0 3.2 351.6
5.00 1197.9 1194.7 690.7 507.2 2.355 2.471 11.4 83.9 4.7 16.1 70.9 4.7 1.04 1191 1238.64 3.70 334.8
1195.8 1192.7 690.2 505.6 2.359 2.668 11.5 84.0 4.6 16.0 71.6 11.6 1.04 1163 1209.52 3.71 326.0
1200.5 1197.1 692.4 508.1 2.356 2.668 11.4 83.9 4.7 16.1 71.0 11.7 1.04 1151 1197.04 3.83 312.5
AVG 2.4 2.6 11.4 83.9 4.6 16.1 71.2 9.3 1.0 1215.1 3.7 324.4
5.50 1202.8 1199.9 695.2 507.6 2.364 2.453 12.6 83.7 3.6 16.3 77.6 3.6 1.04 1321 1373.84 4.30 319.5
1180.3 1176.4 682.7 497.6 2.364 2.668 12.6 83.7 3.6 16.3 77.6 11.4 1.09 1298 1414.82 4.29 329.8
1178.6 1174.8 681.2 497.4 2.362 2.668 12.6 83.7 3.7 16.3 77.2 11.5 1.09 1239 1350.51 3.93 343.6
AVG 2.4 2.6 12.6 83.7 3.7 16.3 77.5 8.8 1.1 1379.7 4.2 331.0
6.00 1185.0 1182.3 685.8 499.2 2.368 2.436 13.8 83.4 2.8 16.6 83.3 2.8 1.04 1163 1209.52 4.63 261.2
1196.0 1191.5 690.6 505.4 2.358 2.668 13.7 83.1 3.2 16.9 81.1 11.6 1.04 1135 1180.4 4.72 250.1
1188.8 1184.0 685.6 503.2 2.353 2.668 13.7 82.9 3.4 17.1 80.2 11.8 1.04 1111 1155.44 4.69 246.4
AVG 2.4 2.6 13.7 83.1 3.1 16.9 81.5 8.7 1.0 1181.8 4.7 252.6
6.50 1172.7 1168.2 675.9 496.8 2.351 2.418 14.8 82.4 2.8 17.6 84.3 2.8 1.04 870 904.8 5.31 170.4
1185.6 1180.8 685.6 500 2.362 2.668 14.9 82.8 2.3 17.2 86.5 11.5 1.04 870 904.8 5.48 165.1
1178.9 1172.4 679.6 499.3 2.348 2.668 14.8 82.3 2.9 17.7 83.7 12.0 1.04 919 955.76 5.69 168.0
AVG 2.4 2.6 14.9 82.5 2.7 17.5 84.8 8.7 1.0 921.8 5.5 167.8
52
CONSTRUCTION OF FLEXIBLE PAVEMENT
4.1 THE CONSTRUCTION OF ROAD PAVEMENT
Pavement is the structure which separates the tyres of vehicles from the underlying
foundation material. Pavement grants friction for the vehicles thus providing comfort to the driver
and transfers the traffic load from the upper surface to the natural soil.
In earlier times before the vehicular traffic became most regular, cobblestone paths were
much familiar for animal carts and on foot traffic load. Storm water drainage and environmental
conditions are a major concern in the designing of a pavement. The roads of the earlier times
depended solely on stone, gravel and sand for construction and water was used as a binding agent to
level and give a finished look to the surface.
All hard road pavements usually fall into two broad categories namely
Flexible Pavement
Rigid Pavement
Figure 4-1: Types of road construction
(b) Flexible pavement (a) Rigid pavement
Figure 4-2: Response of different pavement types to load
53
4.1.1 About the flexible pavement
Flexible Pavements are constructed from bituminous or unbound material and the stress is
transmitted to the sub-grade through the lateral distribution of the applied load with depth.
The FOUR (4) layers of flexible pavement structure
• Sub-grade soil or simply sub-grade
• Sub-base
• Road Base
• Surface layer
Tack Coat Wearing Course
Surface Course
Prime Coat Binder Course
Base Course
Sub Base Course
Subgrade
Figure 4-3: Cross – section of a Flexible Pavement
The function of Flexible Pavement
To provide a level/flat surface for a more comfortable and safe journey
To receive and distribute the load of the vehicle to the ground layers
To protect the sub-grade layers from damage due to exposure of climate change.
The different between flexible pavement and rigid pavement
Table 4-1: The different between flexible pavement and rigid pavement
Flexible pavement Rigid pavement
In flexible pavement, load distribution is based on Rigid pavement most of the load carries by slabs itself.
layered system.
Due to layered system in flexible pavement, structural Rigid pavement, most of the structural capacity
capacity depends on the characteristics of all layers. depends on the characteristics of slab only, because
of low bearing capacity of underlying layers.
In flexible pavements, intensity of load decreases as A rigid pavement, due to minor capacity of underlying
the depth increases or as the load moves to the further layers maximum load intensity reduces in the top most
underlying layers. layers and that is slab.
Flexible pavement has very low modulus of elasticity Modulus of elasticity of rigid pavement is very high,
(less strength). because of high strength and more loads bearing
capacity than as compared to flexible pavements.
In flexible pavements, underlying layers play very Rigid pavements, little function of underlying layers.
important role. Therefore, more roles are playing only Maximum role is playing by the top layer (that is slab)
underlying layers. by itself. Therefore, little influence on sub layers.
54
The Flexible Pavement Works
Figure 4-4: The Flexible Pavement Work
The functions of flexible pavement’s layer:
Table 4-2: The functions of flexible pavement’s layer
Layer Function
Subgrade
i. Subgrade is a layer of natural soil or filled soil, ready to receive
the pavement material over it.
ii. Subgrade is the lowest layer below the road formation level.
iii. It acts as foundation underneath the pavement structural layer.
iv. Must possess enough soil bearing capacity.
Sub-base Sub-base is one course that is constructed with quality materials. This is
the lowest layer of pavement that is constructed onto the sub-grade. The
functions of sub-grade:
i. Support the road base and spreads the force to the sub-grade.
ii. Prepares the drainage using rough materials.
iii. Prepares a cover at any layer that is constructed.
iv. Bears the pressure from heavy vehicles so the sub-grade will not
crack.
v. Prevent the sub-grade from traffic flow.
Road base
Base or road base is the main course to absorb force from surface
directly and spread the force to the thickest layer. This layer is normally
made from broken stones which may be bounded or unbounded. It is
used to help spread traffic load on large area of sub-grade so that the
stress intensity remains within the capabilities of the sub-grade. Thus
undue deformation caused by the consolidation of the sub-grade is
prevented.
Surface layer
i. The wearing course is the top most layers in a pavement.
ii. Provides smooth and dense ridding surface.
iii. Takes up wear and tear due to traffic.
iv. Provides water tight surface against filtration of surface water.
v. Provides hard surface which can withstand the pressure exerted
by tyres of vehicles.
55
4.1.2 Preparation of materials used in the
a. Sub-base
b. Road base
c. Road surface
Preparation of materials used in the sub-base
Materials
Sub-base shall be a natural or artificial mixture of locally available materials such as sand, gravel,
crushed aggregate etc, free from organic matter, clay lumps and other deleterious materials. It shall be
well graded and conform to Table 4.2.2 and the following quality requirements;
Source : Jabatan Kerja Raya, STANDARD SPECIFICATION FOR ROADWORKS, JKR/SPJ/2008-S4,
2008 (page 14)
Preparation of materials used in the Road base
Construction Methods
The FOUR (4) methods for the construction of road base course in flexible pavement
i. Macadam Crusher-Run Road Base
ii. Dry Bound Macadam Road Base
iii. Wet-Mix Road Base
iv. Bituminous Roadbase
v. Cement-Treated Base
Macadam Crusher-Run Road Base
Materials
Crushed aggregate roadbase material shall be crushed rock, crushed gravel or a mixture of crushed rock
and gravel, which shall be hard, durable, clean and essentially free from clay and other deleterious
materials.
The material shall conform to the following physical and mechanical quality requirements;
i. The plasticity index when tested in accordance with BS 1377 shall be not more than 6.
ii. The aggregate crushing value when tested in accordance with MS 30 shall be not more than 25%.
iii. The flakiness index when tested in accordance with MS 30 shall be not more than 25%.
56
iv. The weighted average loss of weight in the magnesium sulfate soundness test (5 cycles) when
tested in accordance with AASHTO Test Method T 104 shall be not more than 18%.
v. The material shall have a CBR value of not less than 80% when compacted to 95% of the
maximum dry density determined in the B.S. 1377 Compaction Test (4.5 kg rammer method)
and soaked for 4 days under a surcharge of 4.5 kg;
vi. The sand equivalent of aggregate fraction passing the No. 4 (4.75 mm) sieve when tested in
accordance with ASTM D 2419 shall be not less than 45%.
vii. The gradation shall comply with the envelope as shown in Table 4.2.3
Source : Jabatan Kerja Raya, STANDARD SPECIFICATION FOR ROADWORKS, JKR/SPJ/2008-S4,
2008 (page 16)
Wet-Mix Road Base
Materials
Aggregate for wet-mix roadbase shall be crushed rock, crushed gravel or a mixture of crushed rock and
gravel, which shall be hard, durable, clean and essentially free from clay and other deleterious materials.
The aggregate shall conform to the following physical and mechanical quality requirements:-
i. The flakiness index when tested in accordance with MS 30 shall be not more than 25%.
ii. The aggregate crushing value when tested in accordance with MS 30 shall be not more than 25%.
iii. The weighted average loss of weight in the magnesium sulfate soundness test (5 cycles) when
tested in accordance with ASSHTO Test Method T 104 shall be not more than 18%.
iv. The sand equivalent of aggregate fraction passing the No. 4 (4.75 mm) sieve when tested in
accordance with ASTM D 2419 shall be not less than 45%.
v. The gradation shall comply with the limits shown in Table 4.2.4.
57
Source : Jabatan Kerja Raya, STANDARD SPECIFICATION FOR ROADWORKS, JKR/SPJ/2008-S4,
2008 (page 17)
Bituminous Road Base
Materials
The materials for bituminous roadbase shall conform to the physical and mechanical quality requirements. The
gradation of the combined coarse and fine aggregates and mineral filler, shall conform to the appropriate envelope
shown in Table 4.2.5.
Source : Jabatan Kerja Raya, STANDARD SPECIFICATION FOR ROADWORKS, JKR/SPJ/2008-S4,
2008 (page 17)
Cement-Treated Base
Materials
(a) Water
Water shall be clean, clear and free from injurious of sewage, oil, acid, strong alkalis or vegetable matter
and it shall be free from clay or silt. If the water is of questionable quality, it shall be tested in accordance
with the requirements of MS 28.
(b) Cement
Cement shall be ordinary Portland cement, and shall comply with the requirements of MS 522.
58
(c) Aggregate
The aggregate shall be selected crushed materials meeting the gradation requirements given in Table
4.2.5. The material shall be free of roots, sod and weeds. The crushed aggregate shall consist of hard,
durable particles of accepted quality, free from an excess of flat, elongated, soft or disintegrated pieces or
objectionable matter. The method used in producing the aggregate shall be such that the finished
product shall be as consistent as practicable. All stones and rocks of inferior quality shall be removed.
The gradation in Table 4.2.6 represents the limits which shall determine suitability of aggregate for use
from the sources of supply.
Source : Jabatan Kerja Raya, STANDARD SPECIFICATION FOR ROADWORKS, JKR/SPJ/2008-S4,
2008 (page 21)
Preparation of materials used in the Road Surface
Materials
(a) Aggregates
Aggregates for asphaltic concrete shall be a mixture of coarse and fine aggregates, and mineral filler. The
individual aggregate shall be of sizes suitable for blending to produce the required gradation of the
combined aggregate, all to the satisfaction of the S.O.
Coarse Aggregate
Coarse aggregate shall be screened crushed hard rock, angular in shape and free from dust, clay,
vegetative and other organic matter, and other deleterious substances.
They shall conform to the following physical and mechanical quality requirements;
ii. The Los Angeles abrasion value when tested in accordance with ASTM C 131 shall be not more
than 25%.
iii. The weighted average loss of weight in the magnesium sulfate soundness test (5 cycles) when
tested in accordance with AASHTO Test Method T 104 shall be not more than 18%.
iv. The flakiness index when tested in accordance with MS 30 shall be not more than 25%.
v. The water absorption when tested in accordance with MS 30 shall be not more than 2%.
vi. The polished stone value when tested in accordance with MS 30 shall be not less than 40 (only
applicable to aggregates for wearing course).
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, and other deleterious substances. They shall conform to
the following physical and mechanical quality requirements;
59
i. The sand equivalent of aggregate fraction passing the No. 4 (4.75mm) sieve when tested in
accordance with ASTM D 2419 shall be not less than 45%.
ii. The fine aggregate angularity when tested in accordance with ASTM C1252 shall be not less
than 45%.
iii. The Methylene Blue value when tested in accordance with Ohio Department of Transportation
Standard Test Method shall be not more than 10 mg/g.
iv. The weighted average loss of weight in the magnesium sulphate soundness test (5 cycles) when
tested in accordance with AASHTO Test Method T 104 shall be not more than 20%.
v. The water absorption when tested in accordance with MS 30 shall be not more than 2%.
Notwithstanding compliance with the requirements of this Specification, limestone aggregates shall not
be permitted for use in wearing course.
The gradation of the combined coarse and fine aggregates, together with mineral filler, shall conform to
the appropriate envelope shown in Table 4.3.3.
Source : Jabatan Kerja Raya, STANDARD SPECIFICATION FOR ROADWORKS, JKR/SPJ/2008-S4,
2008 (page 32)
(b) 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). At the time of mixing with bitumen, 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. The total amount of hydrated lime as mineral
filler shall be limited such that 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. The hydrated lime shall also be treated as an anti-stripping agent.
(c) Bituminous Material
Bituminous binder for asphaltic concrete shall be bitumen of penetration grade 60-70 or 80-100 which
conforms to MS 124, or polymer modified binder.
60
4.1.3 Discuss the construction of road:
a. Sub-base
b. Road Base
c. Road Surface
d. Shoulders
The construction of Sub-Grade Layer
Prepare the sub-grade layer, it is done after placing the drainage system, piping and electric
cable. The sub-grade surface will be compacted levelled and be cut to make camber as in plan. If the
material of the soil did not have a good quality, it will be changed with suitable material.
Base formation covers with 50-75mm sand layer or quarry dust and will be compacted with 8-10 tone
compactors. This job must be done to prevent the clay from absorbing into the stone layer of sub-base
and reduce the shear strength of the pavement.
The construction of sub-base
After the sub-base has been prepared with list materials, it will be placed and constructed into
two layers if the thickness is more than 150mm. Every layer will be compacted according to the plan.
Sub-base layer must be compacted carefully with compactor machine.
Compactors with rubber roller can compact 120mm layer in 12 times. Compacting should start
from the side of the road hen slowly towards the middle of the road in horizontal way. In super-elevated
bends compaction machine will start at the lowest part and slowly towards the higher level. The
finished part is not more than 20mm from the plan.
The construction of road base
Before road base is constructed, sub-grade surface and sub-base must be formed perfectly and
compacted enough. The lowest layer and sub-base must be prepared at least distance of 200m from the
base construction.
The road base in Malaysia is commonly constructed with a material known as crusher run. This
material is place and compacted to on the surface of the road. The road base must be constructed in two
layers of same thickness. Each layer should not exceed 150mm.
Coating
Two types of coating:
Prime Coat (Salut Perdana)
• liquid bitumen, sprayed onto clean unbound roadbase using pressure distributor at the rate of
0.5 – 1 liter/m2
• The temperature must be according to the specifications stipulated.
• MC-70 (50°C -70°C), SS-1K (25°C - 45°C) cured for 24 hours to achieve maximum penetration
Tack Coat (Salut Jelujur)
• shall be sprayed about 50 to 100 yards forward from paver machine for a reasonable time
• bitumen emulsion, sprayed onto bituminous layer, rate 0.25 – 0.55 liter/m2
• RS-1K, 25°C - 45°C
• Carried out in dry, warm weather and dry surface, prevent spattering adjacent trees, furniture
etc, not to be discharged into drains, gutter, keep traffic off
• Equipment – power broom, compressed air blower, pressure distributor
61
Figure 4-5: Coating Work
The construction of road surface
Figure 4-6: The construction of road surface
The road surface is constructed with bitumen materials, such as concrete asphalt, macadam
bitumen and so on. The constructed should be free from dust and waterproof. To construct the surface
layer, the base course must be prepared first. Prime coat is poured onto the road base surface to be a
binder between the road bases and the base course. To pour the prime coat, the temperature must be
according to the specifications stipulated. Base course is built on one layer only with a paver machine
and after this layer is constructed, it is placed before it is compacted. The surface is checked and
corrected if there are any differences. The compacting must be done immediately. It should be
compacted from the side towards the middle of the road. It there is a super elevated bend, then it should
be compacted from lower part to higher part. The type of compactors must be according to the
specifications. Finally wearing course is prepared. Like always, base course should be cleaned before
prime coat is poured. The compacting job is done the same way as the base course.
The construction of road shoulders
Road shoulders are important element of highway system. It consists of furnishing, compacting and
shaping earth, gravel, or paved shoulder.
Paved – constructed as normal bituminous layer
Gravel – using approved material for gravel surfacing
Earth – using suitable material as described in earthwork section
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The functions of a road shoulder are;
i. It prepares a flat support to the road pavement.
ii. Drains the water surface to the road side drain and avoid humidity from diffusion.
iii. Provides space for traffic users to stop by the roadside of the road and also for emergency lane
during overtaking, especially on the one way street road.
iv. Provides lane/ path for pedestrians and cyclists
v. Provides space for traffic signs and guard rails.
The purpose road shoulder design is:
Safety
i. It can provide a factor of safety for road user who accidently
ii. To provide sealed pavement area on the roadside.
iii. Provide space for vehicles to stop during emergency.
iv. Improved sight distances
Structured
i. Protect the sealed pavement from excess deterioration.
ii. Support side of the road pavement
Recreation
i. Increased roadway width to accommodate agricultural
ii. Vehicles for cyclist
Figure 4-7: The types of road shoulder
4.1.4 Priming work in flexible pavement
Premix is the process of surface layer after finishing spraying the prime coat. Usually the
process of paving of the road will use the paving machine. The pavement construction is as follows:
a. Firstly, the trunk will pour the premix (the call to a mixture of aggregate and bituminous oil in
the paver).
b. Paver machine will move forward while premix will pass from the machines slowly.
c. Elevation will be controlled automatically follow the design
d. The temperature must be approximately 150 degrees Celsius.
e. Make sure the condition method follow the standard,
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The preparation and varieties of materials used in flexible pavement road surface
a. Premix
i. Asphaltic concrete
ii. Bituminous Macadam
b. Non premix
i. Cold mix asphalt
ii. Dry sand mix
iii. Wet sand mix
Figure 4-8: The preparation and varieties of materials used in flexible pavement road surface
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Cold mix asphalt
Cold mix asphalt is a mixture of emulsified asphalt and aggregate, produce, placed and compacted an
ambient air temperature. The use of cold mix asphalt is usually limited to relatively low-volume rural
roads. Cold mix asphalt pavement usually requires an overlay of hot mix asphalt or surface treatment to
resist traffic action. The components of cold mix asphalt can be mixed at a central plant or in-situ with a
traveling mixer
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EXERCISE 4
1. State FOUR (4) methods for the construction of road base course in flexible pavement
(4 marks)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
2. State FOUR (4) adventages of using flexible pavement in Malaysia
(4 marks)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
3. Describe the functions and application of prime coats and tack coats during road construction of
flexible pavement
(8 marks)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
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FEEDBACK ON EXERCISE 4
1. State FOUR (4) methods for the construction of road base course in flexible pavement
Macadam Crusher-Run Road Base (4 marks)
_____________________________________________________________________________________
Dry Bound Macadam Road Base
_____________________________________________________________________________________
Wet-Mix Road Base
_____________________________________________________________________________________
Bituminous Roadbase
_____________________________________________________________________________________
Cement-Treated Base
_____________________________________________________________________________________
2. State FOUR (4) adventages of using flexible pavement in Malaysia
To provide a level/flat surface for a more comfortable and safe journey (4 marks)
_____________________________________________________________________________________
To receive and distribute the load of the vehicle to the ground layers
_____________________________________________________________________________________
To protect the sub-grade layers from damage due to exposure of climate change.
_____________________________________________________________________________________
To provide a level/flat surface for a more comfortable and safe journey
_____________________________________________________________________________________
To receive and distribute the load of the vehicle to the ground layers
_____________________________________________________________________________________
To protect the sub-grade layers from damage due to exposure of climate change
_____________________________________________________________________________________
3. Describe the functions and application of prime coats during road construction of flexible
pavement
(8 marks)
Is a sprayed application of a cutback or emulsion asphalt applied to the surface of untreated roadbase using
pressure distributor at the rate of 0.5 – 1 liter/m2
Is poured between the road base surface and binder course
The temperature must be according to the specifications stipulated.
MC-70 (50°C -70°C), SS-1K (25°C - 45°C) cured for 24 hours to achieve maximum penetration
The function of prime coat are
- Coat and bond any lose material
- Harden or toughen the surface
- Waterproof the base during construction
- Plug capillary voids
- Provide adhesion between the base and the next course
66
CONSTRUCTION OF RIGID PAVEMENT
5.1 THE CONSTRUCTION OF RIGID PAVEMENT
5.1.1 Introduction of rigid pavement
Figure 5-1: Rigid Pavement
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67
Cement concrete roads or rigid pavement are very high standard road. They are costliest than all
other types of roads. These roads provide excellent riding surface and pleasing appearance. They are
called rigid pavements because they do not allow any flexibility. As the strength of concrete develops
with time, its 28-day value is taken for specification purposes, though its strength at 7 days is often used
as an initial guideline of the mix’s ultimate strength. Pavement quality concrete generally has a 28-day
characteristic strength of 40 N/mm2, termed C40 concrete. Ordinary Portland cement (OPC) is
commonly used. The cement content for C40 concrete should be a minimum of 320kg/m3. Air content of
up to 5% may be acceptable with a typical maximum water cement ratio of 0.5 for C40 concrete.
These roads although require initial heavy expenditure but because of their long span of life,
excellent riding surface and negligible maintenance cost, they prove cheaper than bitumen roads.
Moreover engineers have more confidence in cement concrete material and they also like to construct
these roads.
A rigid pavement consists of a subgrade/subbase foundation covered by a slab constructed of
pavement quality concrete. The concrete must be of sufficient depth so as to prevent the traffic load
causing premature failure. Appropriate measures should also be taken to prevent damage due to other
causes. The proportions within the concrete mix will determine both its strength and its resistance to
climate changes and general wear. Joints in the concrete may be formed in order to aid the resistance to
tensile and compressive forces set up in the slab due to shrinkage effects.
In Malaysia, rigid pavement roads are:
Air Keroh-Pagoh Highway
Kuala Lumpur-Tanjung Malim Highway
Gurun-Bukit Kayu Hitam Highway
Materials that are used in construction of rigid pavement
• Concrete
• Steel reinforcement
• Aggregate
• Sand
• Joint Sealants
• Damp Proof Layer
5.1.2 The types of joints in rigid pavement
Joints in rigid pavements
Joints are provided in a pavement slab in order to allow for movement caused by changes in
moisture content and slab temperature. Transverse joints across the pavement at right angles to its
centreline permit the release of shrinkage and temperature stresses. The greatest effect of these stresses is
in the longitudinal direction. Longitudinal joints, on the other hand, deal with induced stresses most
evident across the width of the pavement.
There are four main types of joints:
i. Contraction joints
ii. Expansion joints Traverse joint
iii. Warping joints Longitudinal joint
iv. Construction joints
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Contraction joints
Figure 5-2: Contraction joint detail
Contraction occurs when water is lost or temperatures drop. Contraction joints allow induced
Work
stresses to be released by permitting the adjacent slab to contract, thereby causing a reduction in tensile
stresses within the slab. The joint reduces the thickness of the concrete slab, inducing a concentration of
stress and subsequent cracking at the chosen appropriate location. The reduction in thickness is usually
achieved by cutting a groove in the surface of the slab, causing a reduction in depth of approximately
30%. A dowel bar placed in the middle of the joint delivers the requisite vertical shear strength across it
and provides load-transfer capabilities. It also keeps adjacent concrete surfaces level during temperature
induced movements. In order to ensure full longitudinal movement, the bar is debonded on one side of
the contraction joint.
Expansion joints
Figure 5-3: Expansion joint detail
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Expansion occurs when water is absorbed or the temperature rises. Expansion joints differ in
that a full discontinuity exists between the two sides, with a compressible filler material included to
permit the adjacent concrete to expand.
Warping joints
Figure 5-4: Warping joint detail
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69
Warping joints are required in plain unreinforced concrete slabs only. They permit small
angular movements to occur between adjacent concrete slabs. Warping stresses are very likely to occur
in long narrow slabs. They are required in unreinforced slabs only, as in reinforced slabs the warping is
kept in check by the reinforcing bars. They are simply a sealed break or discontinuity in the concrete slab
itself, with tie-bars used to restrict any widening and hold the sides together.
Construction joints
Figure 5-5: Construction joint detail
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Construction is normally organised so that work on any given day ends at the location of an
intended contraction or expansion joint. Where this proves not to be possible, a construction joint can be
used. No relative movement is permitted across the joint.
5.1.3 The types of rigid pavement
There are FOUR (4) types of rigid pavement
i. Unreinforced Concrete (URC)/ Jointed Plain Concrete Pavement
ii. Joined Reinforced Concrete (JRC)
iii. Continuous Reinforced Concrete (CRCP)
iv. Pre-Stress Concrete (PSC)
Unreinforced Concrete (URC)/ Jointed Plain Concrete Pavement
Unreinforced / Jointed plain
concrete pavement (JPCP, Figure
5-6) uses contraction joints to
control cracking and does not use
any reinforcing steel.
Transverse joint spacing is
selected such that temperature
and moisture stresses do not
produce intermediate cracking
between joints.
This typically results in a spacing
no longer than about 6.1 m (20
ft.).
Dowel bars are typically used at
transverse joints to assist in load
transfer.
Tie bars are typically used at
longitudinal joints Figure 5-6: Unreinforced /Jointed Plain Concrete Pavement detail
(Source: http://www.pavementinteractive.org/article/jointed-plain-
concrete-pavement/)
70
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Joined reinforced Concrete Pavement (JRCP)
• Jointed reinforced concrete pavement (JRCP, see Figure 5-7) uses contraction joints and
reinforcing steel to control cracking.
• Transverse joint spacing is longer than that for JPCP and typically ranges from about 7.6 m
(25 ft.) to 15.2 m (50 ft.).
• Temperature and moisture stresses are expected to cause cracking between joints, hence
reinforcing steel or a steel mesh is used to hold these cracks tightly together.
• Dowel bars are typically used at transverse joints to assist in load transfer while the
reinforcing steel/wire mesh assists in load transfer across cracks.
Figure 5-7: Joined reinforced Concrete Pavement detail
(Source: http://www.pavementinteractive.org/article/jointed-reinforced-concrete-pavement/)
Continuous Reinforced Concrete Pavement (CRCP)
Continuously reinforced concrete pavement (CRCP, see Figure 5-8) does not require any
contraction joints.
Transverse cracks are allowed to form but are held tightly together with continuous reinforcing
steel.
Research has shown that the maximum allowable design crack width is about 0.5 mm (0.02
inches) to protect against spalling and water penetration (CRSI, 1996[1]).
Cracks typically form at intervals of 1.1 – 2.4 m (3.5 – 8 ft.).
Reinforcing steel usually constitutes about 0.6 – 0.7 percent of the cross-sectional pavement area
and is located near mid-depth in the slab.
71
Figure 5-8: Continuous Reinforced Concrete Pavement detail
(Source: http://www.pavementinteractive.org/article/continuously-reinforced-concrete-pavement/)
Pre-Stress Concrete (PSCP)
• Mostly done in factory
• Easy installation
• Save cost
Figure 5-10: Pre-Stress Concrete Pavement detail
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72
5.1.4 Differentiate the methods of paving rigid pavement
Mechanised paving allows a higher quality concrete finish to be attained. The spreading,
compacting and finishing of the pavement involves use of a fixed form or slip-form paving train.
Fixed-form
Paving uses steel forms or a preconstructed concrete edge-beam to retain the concrete, using machine
rails to support and guide the individual items of plant utilised in the pavement construction process.A
train of machines, each individually operated, run along the rails, executing the basic tasks of:
i. Spreading the concrete
ii. Compacting it by vibration
iii. Finishing the surface.
Machines for dowel and joint forming that leave the surface of the concrete with the required
texture and the addition of curing compounds may also be included within the process. The machines
themselves may be manually propelled, selfpowered or towed along the rail.
Typical types of machinery used in a fixed-form paving train are:
(1) Feeder – receives concrete as it arrives at the required location
(2) Spreader – distributes the concrete across the full width of the pour in question, discharging it at
a controlled rate
(3) Rotary strike-off paddles and compaction beams – regulate the concrete by trimming any
irregularities in the concrete and vibrate its surface
(4) Dowel/tie-bar placers – place these elements in the appropriate joints either manually or by
vibration
(5) Joint groove formers and finishers –
grooves formed by a knife travelling within
the plastic concrete (wet-formed).
Otherwise, a vibrating blade can be used to
form them when the concrete has hardened
sufficiently
(6) Final finishing equipment – additional
compaction and regulation of the concrete
after the dowel and tie-bars have been put
in place. (Machine uses two oblique
finishing beams oscillating in opposite
directions to achieve a uniform finish to the
surface of the concrete)
(7) Curing compound sprayer
(8) Protective tentage. Figure 5-11: Fixed-form Work
73
Figure 5-12: Diagrammatic representation of fixed-form paving train
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Slip form paver
The previous method is
analogous to manually placing the
concrete. The process can also be
completed without using fixed-forms.
This process is called slip-form paving. It
works on the basis that the sides of the
pavement slab will support themselves
before an initial set has been developed within the concrete. It produces a fully compacted slab. It cannot
therefore be subsequently disturbed in order to place dowel or tie-bars, as the surrounding concrete
could not then be properly made good. The slip-form paver spreads, compacts and finishes the concrete
with only the forming and finishing of the joint grooves, texturing and curing done using other pieces of
equipment.
74
Dowel and tie bar baskets placed in
preparation for Slip form paving
Slip form pavers
Finishing Slip form pavement around a banked
curve
Figure 5-13: Slip form paver
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The slip form paver has certain advantages/disadvantages associated with it:
i. A higher output is achievable as less machinery is involved
ii. It will tend to be less expensive as labour costs will be lower due to the increased level of
automation.
But:
i. Edge slump may occur just after the concrete has left the paver
ii. Greater stockpiles of raw materials such as cement, steel mesh and aggregate are needed in
advance of the operation in order to ensure continued output from the paving train
iii. The contractor operating it may be more vulnerable to weather conditions
iv. A minor quality control failure can cause the entire system to come to a sudden stop.
Compare the methods of paving rigid pavement between manual and mechanical.
Manual Mechanical
Set up side form in certain distance of the pavement Set up side form a long distance of the pavement before
before paving. paving.
Cast the concrete by hand (human labor) Cast the concrete by machine as slip paver and fix pave.
Construction takes a long time Reduce the time of construction period
High labour costs Reduce labour cost
Compacted concrete slab surface use 'Vibrating Compaction and forming operations long-run within the
tamping beam by hand term limits of paving machine
Requires the use wooden or metal side forms that
are set up along the perimeter of the pavement Does not require any steel or wooden forms
before paving
75
EXERCISE 5
1. List FOUR (4) types of joints in cement concrete pavement
(4 marks)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
3. List FOUR (4) advantages of rigid pavement construction
(4 marks)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
3. There are TWO (2) methods of construction in rigid pavement. Compare the methods of paving
rigid pavement between manual and mechanical.
(10 marks)
Manual Mechanical
76
FEEDBACK ON EXERCISE 5
1. List FOUR (4) types of joints in cement concrete pavement
(4 marks)
Expansion joint
_____________________________________________________________________________________
Contraction joint
_____________________________________________________________________________________
Warping Joint
_____________________________________________________________________________________
Construction oint
_____________________________________________________________________________________
2. List FOUR (4) advantages of rigid pavement construction
(4 marks)
They provide excellent smooth surface for driving and provide better visibility.
_____________________________________________________________________________________
They can deal with very heavy traffic.
_____________________________________________________________________________________
Considering their life span more than 30 – 40 years, maintenance cost etc, cement concrete roads prove
_____________________________________________________________________________________
cheaper than bituminous roads.
_____________________________________________________________________________________
Maintenance cost is negligible.
_____________________________________________________________________________________
3. There are TWO (2) methods of construction in rigid pavement. Compare the methods of paving
rigid pavement between manual and mechanical.
(10 marks)
Manual Mechanical
Set up side form in certain distance of the pavement Set up side form a long distance of the
before paving. pavement before paving.
Cast the concrete by machine as slip paver and
Cast the concrete by hand (human labor)
fix pave.
Construction takes a long time Reduce the time of construction period
High labour costs Reduce labour cost
Compacted concrete slab surface use 'Vibrating Compaction & forming operations long-run
tamping beam by hand within the term limits of paving machine
Requires the use wooden or metal side forms that are Does not require any steel or wooden forms
set up along the perimeter of the pavement before
paving
77
TRAFFIC CONTROL EQUIPMENT AND ROAD
FURNITURE
6.1 THE TRAFFIC CONTROL EQUIPMENT AND ROAD FURNITURE IN
HIGHWAY ENGINEERING
Traffic control devices are needed to control the traffic flow to effective
system. The purpose of traffic control, devices and warrants for their
use is to help ensure highway safety by providing for the orderly and
predict able movement of all traffic, motorised and non-motorised, and
to provide the necessary guidance and warnings to ensure the safe and
informed operation of every road user on the highway.
The functions of the traffic control device
Road users depend upon traffic control devices to be advised of the requirements or conditions
affecting road use at specific places and times so that appropriate action can be taken to avoid accidents,
delays etc. Functionally, the traffic control devices in use are divided into the following three groups:
i. Regulatory devices have the authority to impose precise requirements upon the actions of road
users.
ii. Warning devices call attention to potentially hazardous roadway conditions or unusual traffic
movements which are not readily apparent to on-coming traffic. They impose the responsibility
upon the individual road user to employ added caution.
iii. Guiding devices show route designations, destinations, directions, distances, points of interest,
and other geographical or cultural information.
6.1.1 Traffic control devices and signboards
A sign, signal, marking or other device used to regulate, warn or guide
traffic, placed on, over or adjacent to a street, highway, pedestrian facility or
shared-use path by authority of a public agency having jurisdiction.
(MUTCD, 2003). Types of devices :
i. Road Marking
ii. Road studs
iii. Delineators
iv. Traffic signboards
v. Lighting Devices
Figure 6-1: Manual on Uniform
Traffic Control Devices
78
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6.1.2 The category of devices according to their functions
Table 6-1: Devices according to their functions
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6.1.3 The basic characteristics of traffic control device
The characteristics of traffic control devices used.
i. Fulfill a need.
ii. Command attention.
iii. Convey a clear, simple meaning.
iv. Command respect of drivers and pedestrians.
v. Be place so as to give users time for proper response
6.1.4 The importance and functions of traffic control device
The importance of traffic control device
The following factors need to be considered for the Traffic Control Plans:
a) Economic and community
Commercial business districts
Residential locations
Recreation areas
Shopping centres
Railroad crossings
Rural areas
Other work planned adjacent to: or within the area of the project
b) Traffic
Volumes
Bicycle
Large vehicles such as trucks and buses
79
Speed of traffic
Capacity of roadway
Traffic signal operation (effect on existing vehicle detectors)
c) Seasonal changes and weather.
Maintaining traffic control during seasonal shutdowns
loss of visibility and damage to devices during rain
maintenance of traffic control devices (cleaning, cutting vegetation away from signs)
6.1.5 The types of material and color used in preparing road sign/marking
Road pavements may be marked by one or more of the following materials:
i. Paint (reflectorised and nonreflectorised)
Only road line paints conforming to M.S. 164:1973,
tested and approved by SIRIM shall be used. Paint is
best used in situations and on roads where the
markings are not subjected to heavy traffic wear.
Figure 6-2: Paint
ii. Thermoplastics (reflectorised and non-reflectorised)
Thermoplastics used shall be of the hot-applied
thermoplastics material conforming to B.S 3262 or the
equivalence. This material is applied hot and sets on
laying. It has good durability and is recommended to
be used in heavily travelled urban areas and in main
highways with high traffic densities. All road centre
lines shall be in thermoplastics.
Figure 6-3: Thermoplastics
iii. Preformed tapes
Markings in this material take the
form of plastic sheet attached to the
carriageway surface by means of an
adhesive. The markings must be
patterned or embossed in order
secure satisfactory resistance to
skidding. It can be used as
temporary markings because it can
be removed easily even after an
extended time period.
Figure 6-4: Preformed tapes
80
6.2 THE TYPES OF ROAD FURNITURE IN HIGHWAY ENGINEERING
6.2.1 The objectives of road signs
To regulate traffic or to warn or guide road users.
6.2.2 The basic principles of:
a. Road signs
Should be uniform in design, position and application so that they may be recognised and
understood immediately by all road users.
No longer applicable which may create confusion in the mind of the motorist shall be removed
or obliterated as soon as practicable. Other markings and delineations required by road
conditions or restrictions should be remove or obliterated when those conditions cease to exist
or the restrictions are withdrawn.
Must be visible at night shall be reflectorised unless ambient allumination assures adequate
visibility. All markings on highways shall be reflectorised. Even on well lighted town and streets
it is generally desirable markings which must be visible at night be reflectorised.
In addition to reflectorised lines the use of road studs may be considered for roads with poor
alignment or at dangerous situations, for eg. at important junctions and intersections.
Road markings have definite limitations. They may not be clearly visible when wet, and may not
be very durable when subjected to heavy traffic. Therefore they require frequent maintenance.
Their effect on skid resistance requires care in the choice of materials to be used. Finally they
cannot be applied to unsealed roads.
b. Traffic signboards
The FOUR (4) basic principles of traffic signboard
i. Colour
ii. Shape
iii. Size, Wording, and symbol
iv. Material
6.2.3 The color of material, types and specification of:
a. Road studs
Figure 6-5: Road studs
Road studs are integral to traffic safety at night. It consists of a metal base that must be embedded in the
road surface, and separate rubber pad insert into each side of which (for two-way roads) two
longitudinal biconvex reflectors are fitted. Road studs can be temporary or permanent, but both require
high levels of long term retro-reflectivity and excellent adhesion to the road surface.
81
Permanent Road Studs divide into two types:
i. Snow-ploughable Raised Road Studs
These road studs have prisms set in metal castings and installed
in a cut made by a drop saw using 51 cm radius blades
surrounding a number of 46 cm radius blades. The castings are
installed using a 2-part epoxy and are designed to protect prisms
from vehicular traffic and snowplough damage.
ii. Recessed Reflective Road Studs
These road studs are installed in grooves cut in the road by a
specially designed cutting head. The grooves are approximately
1.2 m long for one-way markers and 2.1 m long for two-way
markers. The stud is installed with a 2-part epoxy and sits in the Figure 6-6: Road studs
low point of the groove approximately 1.6 cm below the road
surface.
Temporary Road Studs
These road studs are traditionally used in work zones, spaced from 1.5 m to 24 m apart and installed
with a 2-part epoxy or bitumen. When the work zone needs to be altered, the temporary studs are
removed with little or no damage to the existing surface.
b. Posts delineator
Posts Delineator are effective aids for nighttime driving.
They are considered to be guide, markings rather than warning
devices and should never be substituted for a proper warning sign.
The purpose of delineators is to outline the edge of the roadway
and to indicate the roadway alignment. Post delineators usually
consist of reflector units (glass, plastic, or reflective sheets)
mounted on suitable supports.
Post mounted delineators are beneficial for horizontal
curves over 5°. It should be pointed out that whilst installation of
such delineators or markers will assist night driving, it may also
encourage drivers to increase speed. Unless other safety features
are correspondingly increased, such installation can give drivers a
false sense of security. Measures should be taken to improve the
superelevation of the road at the bend.
Figure 6-7: Post Delineators
Post delineators are simply reflector units mounted on
suitable supports. Both the reflector units and the supports should be of types approved by J.K.R. The
reflector units may be of the circular corner-cube prismatic lens type and shall be not less than 75 mm
diameter. They can also be made of glass, plastic, or reflective sheetings. Reflective sheetings should be
of rectangular shape 180mm x 50mm and should be of the high intensity retro-reflective material.
These reflector units must be capable of clearly reflecting light under normal atmospheric
conditions from a distance of 300 meters when illuminated by the upper beam of standard automobile
lights. Timber posts should be of hardwood timber painted with stripes of black and orange.
82
Figure 6-8: Details Of Post Delineators
(Dimension Are In Milimetres)
c. Traffic signboards
Types of Traffic Sign
a. Regulatory Signs
i) Prohibitive Signs
ii) Mandatory Signs
b. Warning Signs
c. Guide Signs
i) Destination Signs
ii) Distance Signs
iii) Information Signs
- General Service Signs
- Historical & Cultural
- Interest Area Signs
- Recreational Area Signs
- Town Name Signs
- River Name Signs
d. Route Markers
e. Temporary Signs
The types and specifications of materials used on traffic signboards
i. High intensity retro-reflective sheeting
ii. Standard traffic signboards
iii. Guidance signboards
iv. Non-illuminated types of signboards at gentry
83
The colour used in signboards
BROWN
RED BLUE
REKREASI / ORANGE GREEN YELLOW GRAY WHITE
BERHENTI/ TEMPAT PEMBINAAN PANDU ARAH PANDUAN AMARAN AM HUKUMAN HUKUMAN
LARANGAN REHAT PEMANDUAN
Figure 6-9: The colour used in signboard according to their functions
The functions of Colours on Traffic Sign
a. Red on White background or vice versa
i) Prohibitive
ii) Warning for extreme danger
b. White on Blue background
i) Mandatory
ii) Directive (destination and distance)
iii) Inform on general services.
c. White on Green background
i) Inform on river names
ii) Inform on historical and cultural interest areas.
d. Yellow on Dark Green background
i) Inform on recreational areas
e. Black on White background
i) Prohibitive for some cases
ii) Inform on town names
f. Black on Yellow background
i) Warning
g. Black on Orange background
i) Temporary
h. Red on Blue background
i) Prohibitive for some cases
The geometrical shapes for signboards
Shapes and Sizes of Traffic Sign
a. Circular
i) Size when used with traffic signal :
Diameter = 300 mm
ii) Minimum size: Diameter = 600mm
iii) Normal size: Diameter = 750 mm
b. Octagonal
i) Minimum size: Width = 600 mm.
ii) Other size: Width = 900 mm
c. Triangular (Equilateral)
i) Minimum size: Width = 600 mm
ii) Normal size: Width = 750 mm
d. Diamond (square with vertical diagonal)
i) Minimum size: Width 400 mm
ii) Normal size: Width = 600 mm
iii) Other size: Width = 750 mm & 900 mm.
84
e. Rectangular
Size varies according to legend (word message/symbol) on sign.
6.2.4 The advantages and disadvantages of road studs
The advantages and disadvantages of road studs
In nighttime, car drivers could not see where the road ends and where the alignment of road changes in
direction.
The advantages of road studs over conventional line markings are :
Greater effectiveness in wet weather
Greater durability
The vibration and audible noise created by vehicle tyres crossing road studs act as a secondary
warning to the driver
The use of differently coloured reflex lenses permits the imposition of directional control upon
the motorist, e.g. to convey a ‘wrong way’ message
Disadvantages include:
Their high initial cost
Their susceptibility to damage during snow-clearing
They must be attached to a high-quality surfacing that does not require an early over-lay surface
dressing.
6.3 THE CONCEPT OF TRAFFIC SIGNBOARD
6.3.1 The traffic signboard based on their functions
a. Regulation signboards
b. Warning signboards
c. Information Signboards
An example of traffic control equipment for the following traffic control equipment category:
i. Prohibition Sign: Overtake prohibition, U-Turn Prohibition, Turning Prohibition and etc.
Figure 6-10: Prohibition Sign (Source: Jabatan Kerja Raya, MANUAL ON TRAFFIC CONTROL DEVICES
STANDARD TRAFFIC SIGNS, JKR/J(Rb) 0001/80)
85
ii. Warning Sign: Land Slide Warning, Accident Area Warning and etc.
Figure 6-11: Warning Sign
(Source: Jabatan Kerja Raya, MANUAL ON TRAFFIC CONTROL DEVICES STANDARD TRAFFIC SIGNS,
JKR/J(Rb) 0001/80)
iii. Guidance Sign : Hospital Sign, Kilometer Post, Places Sign and etc
Figure 6-12: Guide Information Signs (Source: Jabatan Kerja Raya, MANUAL ON TRAFFIC CONTROL DEVICES
STANDARD TRAFFIC SIGNS, JKR/J(Rb) 0001/80)
86
Figure 6-13: Guide Destination/ Guide Distance Signs and guide route marker
(Source: Jabatan Kerja Raya, MANUAL ON TRAFFIC CONTROL DEVICES STANDARD TRAFFIC SIGNS,
JKR/J(Rb) 0001/80)
iv. Road Marking: Double line, Centre line, zebra crossing and etc
Figure 6-14: Longitudinal Lines
(Source: Jabatan Kerja Raya, MANUAL ON TRAFFIC CONTROL DEVICES STANDARD TRAFFIC
SIGNS, JKR/J(Rb) 0001/80)
87
v. Temporary Signs
Figure 6-15: Temporary Signs
(Source: Jabatan Kerja Raya, MANUAL ON TRAFFIC CONTROL DEVICES STANDARD TRAFFIC SIGNS,
JKR/J(Rb) 0001/80)
SYMBOL TEMPLATES
Figure 6-16: Symbol Templates (Source: Jabatan Kerja Raya, MANUAL ON TRAFFIC CONTROL DEVICES
STANDARD TRAFFIC SIGNS, JKR/J(Rb) 0001/80)
88
EXERCISE 6
1. State FOUR (4) basic characteristics of traffic control device
(4 marks)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
2. State FOUR (4) basic principles of traffic signboard.
(4 Marks)
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
3. Which of the followings are the types of material used in preparing road sign/marking
i. Paint
ii. Thermoplastics
iii. Performed tapes
iv. High intensity retro-reflective sheeting
A. i and ii
B. iii and iv
C. i, ii and iii
D. All of above
89
FEEDBACK ON EXERCISE 6
1. State FOUR (4) basic characteristics of traffic control device
(4 marks)
Full fill the needs of traffic
_____________________________________________________________________________________
Get attention of traffic
_____________________________________________________________________________________
Deliver message/information that is simple and clear
_____________________________________________________________________________________
Get appreciation from road users
_____________________________________________________________________________________
2. State FOUR (4) basic principles of traffic signboard.
(4 Marks)
Colour
_____________________________________________________________________________________
Shape
_____________________________________________________________________________________
Size, Wording, and symbol
_____________________________________________________________________________________
Material
_____________________________________________________________________________________
3. Which of the followings are the types of material used in preparing road sign/marking
i. Paint
ii. Thermoplastics
iii. Performed tapes
iv. High intensity retro-reflective sheeting
A. i and ii
B. iii and iv
C. i,ii and iii
D. All of above
90
FLEXIBLE PAVEMENT DESIGN
7.1 THE BASIC DESIGN OF FLEXIBLE PAVEMENT
Pavement Thickness Design is the determination of required thickness of various pavement layers to
protect a given soil condition for a given wheel load
Aim: to design a structure that will ensure that the transmitted stresses are sufficiently reduced and do
not exceed the capacity of the underlying subgrade.
7.1.1 The factors that are considered in designing the thickness of flexible pavement.
a. Failure criteria
b. Traffic loading
c. Traffic decaying power
d. Environmental effect
Failure criteria
Two failure mechanisms are permanent deformation and cracking of the bituminous layers. The
definition from Croney, failure as transformation shape or deflection of 20mm tire’s lane not speeding
that measuring from ground level.
Slow zone Fast zone
Vertical
Deformation
or
Rutting
Figure 7-1 : A Typical Profile of a Road Cross Section Showing Rutting Along the Wheel Path
91
Traffic Loadings
Protection of the sub-grade from the loading imposed by traffic is one of the primary functions of a
pavement structure. The designer must provide a pavement that can withstand a large number of
repeated applications of a variable-magnitude loading. Traffic loading comprise of :
i. Tire load and pressure
ii. Axle and wheel configurations
iii. Load repetition
iv. Traffic distribution
v. Vehicle Speed
vi. Equivalent Standard Axle (ESA)
Traffic Decaying Power
Every time an axle load acts on a pavement, damage is inflicted onto the pavement. Real traffic
composition is a mixture of varying weights & numbers of axles. According to this concept, one
application of standard axle load inflicts one unit of damage to the pavement.
Environmental Effect
Environment in which a flexible pavement is to be established has an important influence on the
behavior and performance of the various materials in the pavement and sub-grade. Probably the two
climatic factors of major significance are:
Temperature
Moisture
Seepage
from
highlands Water ponding
Seepage through Seepage through
shoulder pavement
Water content rises in subgrade
Subgrade looses strength and stability
Figure 7-2: Environmental Effect
7.2 THE DESIGN OF FLEXIBLE PAVEMENT
7.2.1 The design factors of thickness of pavement
a. Traffic load
The primary loading factors that are important in flexible pavement design are
i. Magnitude of axle load
ii. Wheel Configuration
iii. Volume and Composition of axle load
iv. Tyre pressure and Contact Area
92
The magnitude of maximum loading is commonly controlled by legal load limits. Traffic survey and
loadometer studies are often used to establish the relative magnitude and occurrence of the various
loading to which a pavement during its design life is a very difficult but obviously important task.
Most design procedures provide for an increase in traffic volume on the basis of experience by using
some estimate growth rate.
Single Axle Tandem Axle Tridem Axle
Figure 7-3: Traffic Loading
The standard axle load, Ls, is equivalent to 80kN or 8200kg or 18,000 pounds or 8.16 tonne. One
application of a load L, is equivalent in terms of damage to F applications of the standard load Ls where
Load equivalency factor, F = (L/Ls)
4
Consider only commercial vehicles CV (BTM > 1.5 ton, 3 ton for RN31)
1.5 4 Lorry 9 tonnes
( ) Car 1.5 tonnes 9 4
8.16 ( )
= 0.00114 8.16
= 1.48
18 4
( ) 26 4
8.16 ( )
= 3.67 8.16
= 103.1
Bus 18 tonnes Trailer 26 tonnes
Figure 7-4: Calculation to define load equivalency factor for
different type of vehicles
93
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