University of Babylon
College of Engineering
Department of Civil Engineering
Lectures of Highway Engineering
Forth Stage
01- Cross-Section Elements
02- Earthworks & Mass-Haul Diagram
03- Asphaltic Materials
04- Aggregate
05- Asphalt Paving Mixture
06- Drainage
07- Evaluation of Strength for Subgrade
08- Thickness Design of Flexible Pavement
09- Rigid Pavement
10- The Effect of type and amount of Filler on Asphalt Paving Mix
Prof. Ali Alwash
Asst. Lect. Harith Ajam
Oct-2010
Oct-2010
Lectures of Highway Engineering – Forth Stage
References:
1. Yoder; E. J. and M. W. Witczak, “Principles of Pavement Design”, A Wiley-
Interscience Publication, John Wiley & Sons Inc., U.S.A., 1975.
2. Yaug H. Huang, “Pavement Analysis and Design”, Prentic Hall Inc., U.S.A.,
1993.
3. Paul Croney and David Croney, “The Design and Performance of Road
Pavements”, McGraw Hill, U.S.A., 1998.
4. “AASHTO Guide for Design of Pavement Structures 1993”, AASHTO, American
Association of State Highway and Transportation Officials, U.S.A., 1993.
5. “A Policy on Geometric Design of Highways and Streets 2001”, AASHTO,
American Association of State Highway and Transportation Officials, U.S.A., 2001.
6. Oglesby Clarkson H., “Highway Engineering”, John Wiley & Sons Inc., U.S.A.,
1975.
00-2
References
Nov-2009
Lectures of Highway Engineering – Forth Stage
01- Cross-Section Elements
1. Surface Type:
-
Asphalt concrete (flexible pavement).
-
Plan, simply reinforced & continuously reinforced concrete (rigid pavement).
-
Surface treatment Æ for shoulders.
Choice depending on (‫)اﺧﺘﻴﺎر ﻧﻮع اﻟﺴﻄﺢ ﻳﻌﺘﻤﺪ ﻋﻠﻲ‬:
a.
Applied stresses (‫)اﻻﺟﻬﺎدات اﻟﻤﺴﻠﻄﺔ‬.
b.
Environmental conditions (‫)اﻟﻈﺮوف اﻟﻤﻨﺎﺧﻴﺔ اﻟﻤﺤﻴﻄﺔ‬.
c.
Available materials (‫)اﻟﻤﻮاد اﻟﻤﺘﻮﻓﺮة‬.
d.
Common practice (‫)اﻟﺨﺒﺮة اﻟﺸﺎﺋﻌﺔ‬.
e.
Cost (‫)اﻟﻜﻠﻔﺔ‬.
2. Cross Slop:
0.01 – 0.03 "high type surface"
0.08 "low type surface" Æ shoulders
3. Lane Width:
-
Standard = 3.65m
-
In practice = 3.75 m
-
+0.25m (at shoulders) & +0.5m (at median if barrier curb is found).
Where +0.25m & 0.50m marginal strips.
4. Shoulder: - Surface treatment
Width = 2.5 - 3.0m
Cross-slop = 5 - 8% = 0.05 - 0.08
01-1
Cross-Section Elements
Nov-2009
Lectures of Highway Engineering – Forth Stage
5. Curbs:
-
Barrier (for pedestrian) (‫)ﻻ ﻳﻤﻜﻦ اﺟﺘﻴﺎزﻩ ﺑﺎﻟﻤﺮآﺒﺎت‬
-
Mountable (‫)ﻳﻤﻜﻦ اﺟﺘﻴﺎزﻩ ﺑﺎﻟﻤﺮآﺒﺎت‬
-
Curb & Gutter (‫)أﻧﻮاع ﻣﻦ اﻷرﺻﻔﺔ ﺗﺤﻮي ﻧﻈﺎم ﺗﺼﺮﻳﻒ‬
6. Guard rail (by sheet and column):
Used at hazardous points:
-
at high fill > 3.0m
-
steep grades (‫)اﻧﺤﺪار ﺷﺪﻳﺪ‬
-
sharp curvature (‫)اﻧﺤﻨﺎء ﺷﺪﻳﺪ‬
-
sudden change in alignment
-
restricted sight (foggy ‫)ﻣﻨﺎﻃﻖ اﻟﺮؤﻳﺔ اﻟﻤﻘﻴﺪة( )ﺿﺒﺎﺑﻲ‬
-
near rivers and lakes < 10 - 15m
7. Median:
For:
-
Separating opposite flow
-
Future expansion
W (m)
1.2
12
O (m)
30
9
01-2
Cross-Section Elements
Nov-2009
Lectures of Highway Engineering – Forth Stage
8. Side walk (‫)ﻃﺮﻳﻖ اﻟﻤﺸﺎة‬:
9. Side slop:
a. Cut slop:
-
For normal soil (clay, silt, sand), & h ≤ 6.0m:
H:V = 2:1, … ..., 4:1 (favorable 4:1 ‫)اﻟﻤﻔﻀﻠﺔ‬
-
For normal soil, & h > 6.0m:
(has to be design according to slop stability theory)
-
For rocky soil:
Hard (H:V) = 1:10 … 1:5
Medium (H:V) = 1:4 … 1:3
Sift (H:V) = 1:2 with steps
b. Fill slop:
،‫أول ﺳ ﺘﺔ أﻣﺘ ﺎر ﺑﺎﻟﻤﻴ ﻞ اﻟﻤﺒ ﻴﻦ ﺑﺎﻟﺸ ﻜﻞ‬
(1:1) ‫( ﺑﺎﻟﻤﻴﻞ‬h) ‫واﻟﻤﺘﺒﻘﻲ‬
01-3
Cross-Section Elements
Nov-2009
Lectures of Highway Engineering – Forth Stage
‫ﻓ ﻲ ﺣﺎﻟ ﺔ وﺟ ﻮد ﻣﺴ ﻄﺢ ﻣ ﺎﺋﻲ ﺑﺠﺎﻧ ﺐ اﻟﻄﺮﻳ ﻖ ﺗﻜ ﻮن‬
‫اﻟﺘﻔﺎﺻﻴﻞ آﻤﺎ ﻓﻲ اﻟﺸﻜﻞ‬
10.
Vertical clearance:
For roads = min. 5.20m
For railway = min. 6.50m
For walkway = min. 2.50m
For main rivers = min. 6.50m
For other rivers = min. 3.50m
For high tension lines = min. 8.8 -10m
11.
Right of way (‫ ≥ )ﻣﺤﺮﻣﺎت اﻟﻄﺮﻳﻖ‬80m
Freeway ≈ 200m
Highway ≈ 100m
Used for: future expansion (‫)اﻟﺘﻮﺳﻊ‬, safety (‫)اﻷﻣﺎن‬, maintenance (‫)اﻟﺼﻴﺎﻧﺔ‬.
01-4
Cross-Section Elements
Nov-2009
Lectures of Highway Engineering – Forth Stage
02-Earthworks & Mass-Haul Diagram
Mass-haul diagram:
Continuous curve showing the relationship between the accumulated algebraic
sums of corrected earthwork volume and distance for the purpose of minimizing the
cost of excavating hauling & damping the materials (Soil).
-
Rising Æ Cut
-
Falling Æ Fill
-
Steep slop Æ High cut or fill
-
Zero slop Æ Change from cut to fill or vice versa.
-
Zero value Æ Balance between cut and fill
Haul (‫ = )اﻟﻨﻘﻞ‬Volume (m3) * Distance (sta.)
Haul distance:
The distance of moving the masses of soil from one place to another, in the
process of earthwork.
02-1
Earthworks & Mass-Haul Diagram
Nov-2009
Lectures of Highway Engineering – Forth Stage
Free haul distance (F. H. D.):
The distance within which there is a fixed price for excavating, hauling, and
damping the materials regardless of the distance moved.
Free haul ch arg e =
I.D
m3
Over haul distance (O. H. D.):
The distance beyond (F. H. D.) for which there is an additional price for each
(m3.sta.)
Over haul ch arg e =
max . O. H. D. =
I.D
m3.sta.
Borrow ch arg e
O. H. ch arg e
Limit of economical haul distance (L. E. H. D.):
The distance beyond which it is more economical to waste and borrow rather
than to pay for the cost of over hauling.
L. E. H. D. = F. H. D. + max. O. H. D.
A-B = F. H. D.
C-D = F. H. V.
E-F = L. E. H. D.
G-H = O. H. V.
E-K = West (W)
F-P = Borrow (B)
‫وآﻤﺜﺎل ﺗﺮﺳﻢ اﻟﻌﻼﻗﺔ ﺑﻴﻦ اﻟﻤﺴﺎﻓﺔ )ﺑﺎﻟﻤﺤﻄﺎت( ﻣ ﻊ اﻟﺤﺠ ﻮم اﻟﻤﺼ ﺤﺤﺔ اﻟﻤﺠﻤﻌ ﺔ ﻟﻘ ﻴﻢ ﻣﻌﻴﻨ ﺔ ﺑﻤﻘﻴ ﺎس رﺳ ﻢ ﻣﻌ ﻴﻦ ﻟﻠﺤﺼ ﻮل‬
‫( وﺣﺴ ﺐ ﻣﻘﻴ ﺎس اﻟﺮﺳ ﻢ ﺗﺮﺳ ﻢ وﺗﻘ ﺎس‬3Sta.) ‫( هﻲ ﻣﺴﺎﻓﺔ اﻟﻨﻘﻞ اﻟﺤﺮ وﻣﻘﺪارهﺎ ﻟﻠﻤﺜﺎل ﺣ ﻮاﻟﻲ‬A-B) ،‫ﻋﻠﻰ ﻣﺨﻄﻂ ﻧﻘﻞ اﻟﻜﺘﻞ وﻣﻨﻬﺎ‬
‫ ﺛ ﻢ ﻧﺮﺳ ﻢ اﻟﺤ ﺪ اﻻﻗﺘﺼ ﺎدي ﻟﻤﺴ ﺎﻓﺔ‬.(F. H. V.) ‫( وه ﻲ ﺣﺠ ﻢ اﻷﺗﺮﺑ ﺔ اﻟﻤﻨﻘﻮﻟ ﺔ ﺑﺼ ﻮرة ﺣ ﺮة‬A-B) ‫اﻟﻤﺴﺎﻓﺔ ﻣﻦ ﻗﻤﺔ اﻟﻤﻨﺤﻨﻲ ﻟﻠﺨ ﻂ‬
‫ أﻣ ﺎ‬،‫( هﻲ ﺣﺠﻢ اﻟﺘﺮﺑﺔ اﻟﻤﻨﻘﻮﻟ ﺔ ﺑﺼ ﻮرة ﻣﻀ ﺎﻓﺔ ﺑﺼ ﻮرة ﻣﻨﺎﺳ ﺒﺔ‬G-H) ‫( وﺣﺴﺐ ﻣﻘﻴﺎس اﻟﺮﺳﻢ ﻓﺘﻜﻮن اﻟﻤﺴﺎﻓﺔ‬L. F. H. D.) ‫اﻟﻨﻘﻞ‬
.‫( اﻟﻔﺎﺋﺾ واﻟﻤﺴﺘﻌﺎر‬W, B) ‫( ﻓﻬﻲ‬E-F) ‫اﻟﺒﺎﻗﻲ ﺗﺤﺖ‬
02-2
Earthworks & Mass-Haul Diagram
Nov-2009
Lectures of Highway Engineering – Forth Stage
Correction:
M
M
* Sandy, Silty clay
‫ﺗﺤﻤﻴﻞ‬
Shrinkage: 5 – 15 % ≈ 10%
Loose
V0
M
‫ﺣﺪل‬
V1
V2
V0 < V2 < V1
M
M
* Lime stone, Sand stone
‫ﺗﺤﻤﻴﻞ‬
Bulking: 25 – 35 % ≈ 30%
V0
Loose
M
‫ﺣﺪل‬
V1
V2
V2 < V1
V2 > V0
Ex.:
Sta.
End Area
(m2)
Cut Fill
4.0
2.6
0+00
2+00
2
4+00
1.0
6+00
7
9+00
0
Cut + (m3)
(-)
Shrinkage
10% (m3)
Corrected
Cut + (m3)
Fill – (m3)
Balance
Vol. (m3)
(Cut-Fill)
0.5*(4+2)*200
=600
600*0.1
=60
600-60
=540
0.5*(2.6+0)*200
=260
+280
0.5*(2+1)*200
=300
300*0.1
=30
300-30
=270
0.5*(0+3)*200
=300
-30
0.5*(1+7)*200
=800
800*0.1
=80
800-80
=720
0.5*(3+2)*200
=500
+220
0.5*(7+0)*300
=1050
1050*0.1
=105
1050-105
=945
0.5*(2+8)*300
=1500
-555
0
Accu.
Vol.
(m3)
0
+280
3
+250
2
+470
8
-85
M-H. Diagram
Corrected accumulated volume
(m3)
500
400
300
200
100
0
0
100
200
300
400
500
600
700
800
900
1000
-100
Distance (Sta.)
02-3
Earthworks & Mass-Haul Diagram
Nov-2009
Lectures of Highway Engineering – Forth Stage
03-Asphaltic Materials
Axel Load
M. S. = (Marshall Stability)
C.B.R. = (California bearing reaction)
Flexible Pavement Layers:
M. S. ≥ 8 kN ≈ 10 kN
M. S. ≥ 7 kN
Wearing (Surface) course
Level (Binder) course
(Asphaltic concrete)
(Asphaltic concrete)
M. S. ≥ 5 kN
C. B. R. ≥ 80%
C. B. R. ≥ 35%
C. B. R. ≥ 5% ≈ 10%
Base course
- Asphaltic concrete
- Crushed stone
- Subbase course
Compacted subgrade
(Concrete)
(Stabilized mater) (asphalt, concrete, lime)
(Sand-gravel)
C. B. R. < 5% ≈ 4%
Natural subgrade
Asphaltic Concrete:
-
Asphalt cement
-
Coarse aggregate (crushed gravel) [1" – No.4 (No.10)]
-
Fine aggregate (sand) [No.4 (No.10) – No.200]
-
Mineral filler (cement or lime) [≤ No.200]
-
Additives
Bituminous materials:
Mixture of hydrocarbons (C, H), liquid or semisolid in consistency, soluble in
CS2 & CCl4
-
Tar: produced by destructive distillation of coal (chemical change), cannot
found in nature, more susceptible to temp. & more toxis.
-
Asphalt: produced by fractional distillation of petroleum (physical change),
natural (lakes, rocks) or manufactured, less susceptible to temp. & less toxic.
Dura refinery:
Atmosphere
Tower
Vacuum
Tower
Medium
distillation
Steam
Deasphaltive
unit
Steam
(deasphaltive
oil)
Propane C3H8
o
370 C
Red need oil
≈ 40%
Blending (a) and (b) (‫)ﺑﻌﺾ ﺣﺎﻻت اﻟﻤﺰج‬
to produce asphalt cement:
Vacuum
(a) residue
≈ 18%
Heavy
distillation
Base
(b) Asphalt
≈ 13%
Blend
1 (a) + 1 (b) Æ AC (40-50)
1.8 (a) + 1 (b) Æ AC (60-70)
03-1
‫اﻟﻨﻔﻂ اﻟﺨﺎم ﺑﻌﺪ اﻟﺘﻘﻄﻴﺮ‬
Crude oil
100%
[315oC]
Light
distillation
Asphaltic Materials
Gasoline
Kerosene
Diesel Oil
Lube Oil
Asphalt +
Paraffin
Nov-2009
Lectures of Highway Engineering – Forth Stage
Manufactured Asphalt
Asphalt Cement
Liquid (Cut-back) Asphalt
Emulsified Asphalt
A) Asphalt Cement:
a. Penetration grade:
40-50
‫ اﻧﺘﺎج ﻗﻠﻴﻞ‬50-60
60-70
85-100
120-150
200-300
Less durable (‫)ﻗﻠﻴﻞ اﻟﺪﻳﻤﻮﻣﺔ‬
Less flexible (‫)ﻟﺪوﻧﺔ ﻗﻠﻴﻠﺔ‬
(Thermal Cracking)
More temperature susceptible
(permanent deformation)
(Rutting)
b. Viscosity grade:
Absolute viscosity (Dynamic): By Poise (
dyne * sec .
)
cm 2
⎡ dγ (shear strain ) ⎤ rate of shear strain ⎜⎝ sec . ⎟⎠
⎛ dyne ⎞
τ(shear stress ) ⎜
= η(Abs.Vis. (Poise) ).⎢
⎥ ←⎯ ⎯ ⎯ ⎯ ⎯⎯⎯
2 ⎟
⎝ cm ⎠
⎣ dt ( time (sec .)) ⎦
⎛ 1 ⎞
‫ﻗﻠﻴﻞ اﻻﻧﺘﺎج‬
‫ﻣﻬﻢ‬
Viscosity grade
AC-40
AC-20
AC-10
AC-5
AC-2.5
o
Abs. Vis. @60 C =
40*100=4000 poise
2000 poise
1000 poise
500 poise
250 poise
Penetration grade
> 20
> 40
> 70
> 120
> 200
Asphalt cement requirements (AC-20 [40-70]):
1. Basis of grading (Consistency) (‫)اﻟﻘﻮام‬
-
Abs. Viscosity @60oC = (1600 – 2400) poise
(Gs = 1.01 – 1.05)
2. Temperature susceptibility (‫)ﺣﺴﺎﺳﻴﺘﻬﺎ ﻟﻠﺤﺮارة‬:
-
Penetration (‫)ﻓﺤﺺ اﻟﻐﺮز‬: (ST. condition – min. 40 (40-70) 1/10mm
Penetration after thin film oven test, retained pen. > 55% & (mass loss < 0.75%)
-
Kinematics viscosity @135oC Æ Min. (210) Centistokes
(Stokes = 100 Centistokes) (Stoke = Poise/Density)
03-2
Asphaltic Materials
Nov-2009
Lectures of Highway Engineering – Forth Stage
3. Oxidative hardening (‫)اﻟﺘﺼﻠﺐ ﺑﺴﺒﺐ اﻻآﺴﺪة‬:
-
Abs. viscosity @60oC after thin film oven test Æ Min. (10000) Poise
4. Homogeneity (‫)اﻟﺘﺠﺎﻧﺲ‬:
-
Ductility after thin film oven test Æ Min. (20cm)
Ductility before thin film oven test Æ (≥ 100cm)
@25oC (5cm/min.)
-
Solubility in Trichloro-Ethelin Æ Min. (99%)
5. Safety:
-
Flash point Æ Min. (232oC)
-
Softening point Æ (52 – 60oC)
Chemical components (AC):
-
Aliphatic hydro carbons (Chain)
H
H
H
H
|
|
|
|
H − C − C − C − C − H
|
|
|
|
Light molecular weight
H
H
H
H
H
|
-
Aromatic hydro carbons (Rings)
C
Heavy molecular weight
H −
/
C
\\
C − H
||
|
H −
C
C
\\
/
− H
C
|
H
Chemical Components:
:‫وﺟﺪ أن ﺗﺮآﻴﺐ ﻋﻴﻨﺔ ﻣﻦ اﻻﺳﻔﻠﺖ هﻮ‬
[C89 H104 S3 N2 O2]
:‫وﺗﺨﺘﻠﻒ أﻧﻮاع اﻻﺳﻔﻠﺖ ﻓﻲ ﻧﺴﺐ هﺬﻩ اﻟﻌﻨﺎﺻﺮ وﺗﺘﺮاوح ﺿﻤﻦ اﻟﺤﺪود اﻵﺗﻴﺔ‬
C = 70 – 85 %,
H = 7 – 12 %,
O = 0 – 5 %,
N=0–1%
S=1–7%
03-3
Asphaltic Materials
Nov-2009
Lectures of Highway Engineering – Forth Stage
Fractional
Components of
AC
Asphaltene 1 Asphaltene
2 Nitrogen bases
Maltenes
Role
Bonding agent (‫)اﻟﻘﻮام‬
Peptizing agent ( ‫ﻳﺴﺎﻋﺪ ﻋﻠﻰ اﻧ ﺪﻣﺎج اﻻﺳ ﻔﻠﺘﻴﻦ ﺑ ﺎﻻﺟﺰاء‬
‫)اﻻﺧﺮى‬
3 First acidaffines
Solvent (‫)ﻣﻮاد ﻣﺬﻳﺒﺔ ﺗﺴﺎﻋﺪ ﻋﻠﻰ اﺣﺘﻮاء اﻟﻤﻮاد اﻻﺧﺮى‬
4 Second acidaffines Solvent (‫)ﻣﻮاد ﻣﺬﻳﺒﺔ ﺗﺴﺎﻋﺪ ﻋﻠﻰ اﺣﺘﻮاء اﻟﻤﻮاد اﻻﺧﺮى‬
5 Paraffin
Gelling agent (‫)ﻋﺎﻣﻞ ﻣﺨﺜﺮ‬
(Durability)
Reactivity
to O2
Low
High
High
Low
Very low
B) Liquid (cut-back) Asphalt:
Asphalt cement + solvent (for temporary liquefaction)
a. Rapid Curing (R.C):
AC (85-100) + Gasoline
RC-70 (ً‫)اﻻآﺜﺮ ﺷﻴﻮﻋﺎ‬
RC-250
RC-800
RC-3000
‫ ﻟﻠﻤﻨﺎﻃﻖ اﻟﺤﺎرة‬Kinamatic Vis. @60oC = 70-2*70 centestok
‫ﻟﻠﻤﻨﺎﻃﻖ اﻟﺒﺎردة‬
Used as Tack Coat: Thin film of asphalt applied (immediately before paving)
between 2-paved layers (0.2-0.5 litter/m2)
b. Medium Curing (M.C):
AC (120-150) + Kerosene
MC-30
MC-70 (ً‫ )اﻻآﺜﺮ ﺷﻴﻮﻋﺎ‬Tight Surface (‫)ﻣﺴﺎﺣﺎت ﺻﻐﻴﺮة‬
MC-270 (ً‫ )اﻻآﺜﺮ ﺷﻴﻮﻋﺎ‬Open Surface (‫)ﻣﺴﺎﺣﺎت آﺒﻴﺮة‬
MC-800
MC-3000
Used as Prime Coat: Film of asphalt applied (before 24hr of paving) between
unpaved & paved layers (1.0-0.5 litter/m2)
c. Slow Curing (S.C):
AC (200-300) + Oils
SC-70
SC-250
SC-800
SC-3000
For stabilizing earth works (‫)ﻟﺘﺜﺒﻴﺖ اﻷﻋﻤﺎل اﻟﺘﺮاﺑﻴﺔ‬
03-4
Asphaltic Materials
Nov-2009
Lectures of Highway Engineering – Forth Stage
C) Emulsified Asphalt:
Dispersing of asphalt particles in water in presence of emulsifying agent
AC (non-polar) + Water (polar H+OH-) + surface active agent (emulsifier)
‫ اﻟﻤ ﺎدة اﻟﻤﺴ ﺎﻋﺪة ﺗﻤ ﻨﺢ ذرات اﻹﺳ ﻔﻠﺖ ﻗﻄﺒﻴ ﺔ ﻟﺘﻜ ﻮن ﻣﺴ ﺘﺤﻠﺒﺔ ﻓ ﻲ‬،‫ اﻟﻤﺎء ﻣ ﺎدة ﻣﺘﺄﻳﻨ ﺔ‬،‫* اﻹﺳﻔﻠﺖ ﻣﺎدة ﻏﻴﺮ ﻣﺘﺄﻳﻨﺔ‬
‫اﻟﻤﺎء‬
‫* ﺑﻌﺾ اﻟﻤﻮاد اﻟﻤﺴﺎﻋﺪة ﺗﻀﻴﻒ ﺷﺤﻨﺎت ﻣﻮﺟﺒﺔ أو ﺳﺎﻟﺒﺔ أآﺒﺮ ﻣﻦ اﻟﺜﺎﻧﻴ ﺔ واﻟﺘ ﻲ ﺗﺴ ﻤﺢ ﻓ ﻲ اﻟﺤﺼ ﻮل ﻋﻠ ﻰ ﺑﻌ ﺾ‬
‫اﻟﺨﻮاص ﻟﻠﻤﺎدة اﻟﻤﺴﺘﺤﻠﺒﺔ‬
For:
1. Possibility of mixing with aggregate at normal temperature.
2. Water is safer and cheaper.
:‫ﺗﺴﺘﻌﻤﻞ اﻟﻤﺴﺘﺤﻠﺒﺎت ﻋﻨﺪ اﻟﻤﺰج ﻣﻊ اﻟﺮآﺎم ﻷﻧﻬﺎ ﺗﻮﻓﺮ‬
‫ اﻣﺘﺰاج اﻹﺳﻔﻠﺖ ﺑﺴﻄﺢ اﻟﺮآﺎم‬.1
‫ إزاﻟﺔ اﻟﻤﺎء اﻟﻤﻮﺟﻮد ﻓﻲ ﻓﺠﻮات اﻟﺮآﺎم‬.2
‫* ﻳﺤﺘﻮي ﺳﻄﺢ اﻟﺮآﺎم ﻋﻠﻰ ﺷﺤﻨﺎت ﻗﻄﺒﻴﺔ ﻣﻌﻴﻨﺔ ﻟﺬﻟﻚ اﺧﺘﻴﺎر ﻧﻮع اﻟﻌﺎﻣﻞ اﻟﻤﺴ ﺎﻋﺪ ﻳﺴ ﺎﻋﺪ ﻋﻠ ﻰ إﻳﺠ ﺎد ﺗ ﺮاﺑﻂ ﺑ ﻴﻦ‬
:‫ آﻤﺎ ﻓﻲ اﻟﻤﺨﻄﻂ أدﻧﺎﻩ‬،‫اﻹﺳﻔﻠﺖ وﺣﺒﻴﺒﺎت اﻟﺮآﺎم ﺑﺼﻮرة أﻓﻀﻞ‬
Emulsifying Type
Anionic Emu. Asp.
agent
(Quality)
Cationic Emu. Asp.
Quantity
With lime stone (+)
With Quartz & Silica (-)
Rapid setting
As (tack coat)
Medium setting
As (prime coat with coarse agg.)
Slow setting
As (prime coat with fine agg.)
Anionic Emu. Asp.
RS-1 & RS-2
MS-1, MS-2
MS-h
SS-1 & SS-1h
Cationic Emu. Asp.
CRS-1 & CRS-2
*
& CMS-2 & CMS-2h
CSS-1 & SCC-1h
(-) ‫ ﻓﻲ ﺑﺪاﻳﺔ اﻟﺮﻣﺰ ﻣﻌﻨﺎﻩ أن اﻟﺸﺤﻨﺔ ﺳﺎﻟﺒﺔ‬C *
Setting: coalesance (separation) of asphalt from water
Note:
(2) more viscose than (1) (‫)أآﺜﺮ ﻟﺰوﺟﺔ‬
(2h) harder asphalt (residue) (‫ )اﻟﻤﺘﺒﻘﻲ ﺑﻌﺪ ﺗﺒﺨﺮ اﻟﻤﺎء‬than (2)
(1h) harder asphalt (residue) than (1)
03-5
Asphaltic Materials
Nov-2009
Lectures of Highway Engineering – Forth Stage
Important properties of Asphalt:
1. Hardening with time (Oxidation, Volatilization of light components)
‫زﻳﺎدة اﻟﺼﻼﺑﺔ ﺑﻤﺮور اﻟﺰﻣﻦ ﺑﺴﺒﺐ اﻟﺘﺄآﺴﺪ وﺗﺒﺨﺮ اﻟﻤﻮاد اﻟﻤﺬﻳﺒﺔ اﻟﺨﻔﻴﻔﺔ‬
2. Thermoplastic materials (Consistency varies with temperature)
(η) ‫ﻣﺎدة ﻣﺮﻧﺔ ﺑﺎﻟﺤﺮارة )اﻟﻠﺪوﻧﺔ ﺗﺘﻐﻴﺮ ﺑﺘﻐﻴﺮ اﻟﺤﺮارة( وﻣﻘﻴﺎس اﻟﻠﺪوﻧﺔ هﻲ اﻟﻠﺰوﺟﺔ‬
Log η
(Abs. Viscosity)
Log T (Temp.)
(Abs. Temp.)
3. Rheological materials (Stress-Strain behavior is time depending)
‫ وﻟﺪراﺳﺔ وﺗﻤﺜﻴﻞ ﺗﺼﺮف اﻟﻤﻮاد اﻻﺳﻔﻠﺘﻴﺔ اﻟﺘﻲ هﻲ وﺳﻂ ﺑﻴﻦ اﻟﻤﻮاد‬،‫هﻨﺎك ﻋﻼﻗﺔ ﺑﻴﻦ اﻻﺟﻬﺎد واﻻﻧﻔﻌﺎل ﻣﻊ اﻟﺰﻣﻦ‬
:‫ وآﻤﺎ ﻳﺄﺗﻲ‬.‫اﻟﻠﺪﻧﺔ واﻟﻤﻮاد اﻟﻠﺰﺟﺔ ﻳﺠﺐ دراﺳﺔ ﺗﺼﺮﻓﺎت اﻟﻤﻮاد اﻟﺒﻼﺳﺘﻴﻜﻴﺔ واﻟﻠﺰﺟﺔ‬
Elastic materials:
-
Stress-strain in time independent.
-
No permanent deformation (all recoverable after unloading).
-
Instantaneous deformation while loading.
-
Follow Hook's low.
τ (shear stress) = G (shear modulus) * γ (shear strain)
-
"Spring" may represent such behavior.
τ = constant
γ
‫ﺑﻘﺎء اﻟﺘﺸﻮﻩ ﺑﺒﻘﺎء اﻟﺤﻤﻞ‬
(Spring) ‫ﻋﻨﺪ ﺗﺴﻠﻴﻂ اﻟﺤﻤﻞ ﻋﻠﻰ‬
‫ﺣﺪوث ﺗﺸﻮﻩ ﺁﻧﻲ‬
tu
t
Unload time
03-6
Asphaltic Materials
Nov-2009
Lectures of Highway Engineering – Forth Stage
Viscous materials:
-
Stress-Strain is time dependent.
-
No immediate deformation.
-
No recovery of deformation (all deformation are permanents).
-
Follows Newton's law.
τ (shear stress) = η(abs. vis.)
-
dγ
(rate of shear strain)
dt
Dash-pot may represent such behavior.
τ = constant
γ
‫ﺑﻌﺪ رﻓﻊ اﻟﺤﻤﻞ‬
‫ﻋﻨﺪ اﻟﺘﺤﻤﻴﻞ‬
(‫)ﺗﺸﻮﻩ ﺗﺪرﻳﺠﻲ‬
τ
η
‫ﺛﻘﻮب‬
Asphalt
t
tu
Unload time
But Asphalt may be viscoelastic material.
:‫وﻟﻠﺘﻌﺒﻴﺮ ﻋﻦ هﺬﻩ اﻟﺤﺎﻟﺔ هﻨﺎك ﻣﺠﻤﻮﻋﺔ ﻣﻦ اﻟﻤﻮدﻳﻼت اﻟﺮﻳﺎﺿﻴﺔ‬
By Maxwell model:
τ=η
dγ ← γ 2
dt ← tu
γ1
τ * tu
γ2 =
η
γtotal = γ1 + γ2
γ total
τ τ
= + * t ← Anytime
G η
γ
γ1 =
γ2
γ2
τ
η
τ
G
γ2 =
γ1
τ * tu
η
tu
03-7
t
Asphaltic Materials
Nov-2009
Lectures of Highway Engineering – Forth Stage
By Kelvin or Voight model:
γ=
γ
γ=
τ
*F
G
F≤1
When t = ∞
τ
G
τ
G
− t⎞
τ⎛
γ = ⎜1 − e η ⎟
⎟
G ⎜⎝
⎠
G
tu
F = 1− e
γ=
τ
G
t
G
− *t
η
No instantaneous deformation
No permanent deformation
But related elasticity
By Burger (4-element) model [of asphaltic material]:
γ1
η2
γ2
γ
elastic
G1
G2 inelastic
γ1 =
γ3
τ
η3
γ2
γ3
η3
viscous
τ
G1
γ2
γ3 =
γ1
τ
* tu
η3
tu
t
For loading curve:
G
− 2t ⎞
τ
τ ⎛⎜
τ
γ=
+
1 − e η2 ⎟ + * t
⎟ η3
G1 G 2 ⎜⎝
⎠
:‫ﻣﻼﺣﻈﺔ‬
‫ﻟﻄﺒﻘﺎت اﻟﺘﺒﻠﻴﻂ اﻟﻤﺮﻧﺔ ﻳﻜﻮن ﻓﻴﻬﺎ ﻗﺴﻢ ﻣﻦ اﻟﺘﺸﻮﻩ وﻗﺘﻲ ﻳﺮﺟﻊ ﺑﺴﺮﻋﺔ وﻗﺴﻢ ﺁﺧﺮ ﻳﺮﺟﻊ ﺑﻤﺮور اﻟﺰﻣﻦ واﻟﻘﺴﻢ اﻟﺜﺎﻟ ﺚ ﺻ ﻐﻴﺮ‬
‫ )اﻟﻘﺴﻢ اﻟﺜﺎﻟﺚ ﻳﺤ ﺪث ﻏﺎﻟﺒ ًﺎ ﻓ ﻲ ﺟﺎﻧ ﺐ اﻟﻤﻤ ﺮ اﻟﺨ ﺎرﺟﻲ ﻟﻠﻄﺮﻳ ﻖ ﺣﻴ ﺚ اﻷﺣﻤ ﺎل اﻟﻤﺮورﻳ ﺔ اﻟﺒﻄﻴﺌ ﺔ‬.‫أو ﻗﻠﻴﻞ اﻟﺤﺪوث ﻳﻜﻮن ﻓﻴﻬﺎ داﺋﻤﻲ‬
((Parking) ‫ وآﺬﻟﻚ ﻳﺤﺪث ﻓﻲ ﻣﻨﺎﻃﻖ اﻟﻮﻗﻮف‬،‫واﻟﺜﻘﻴﻠﺔ وﻋﺪم آﻔﺎءة اﻟﺘﺒﻠﻴﻂ‬
03-8
Asphaltic Materials
Nov-2009
Lectures of Highway Engineering – Forth Stage
04-Aggregate:
Natural
Igneous (Granite)
Sedimentary (sand, gravel, sandstone, and limestone)
Metamorphic (Marble)
Industrial product
Slag (‫)ﻣﺨﻠﻔﺎت أﻓﺮان اﻟﺤﺪﻳﺪ‬
Clinker (‫)ﻣﺨﻠﻔﺎت أﻓﺮان اﻟﻔﺤﻢ‬
Main desirable properties of aggregate:
1) Inter particle friction (Mechanism of load transfer):
:‫ وﻳﻤﻜﻦ اﻟﺴﻴﻄﺮة ﻋﻠﻴﻪ ﻣﻦ ﺧﻼل‬،(‫ﻣﻴﻜﺎﻧﻴﻜﻴﺔ اﻧﺘﻘﺎل اﻷﺣﻤﺎل )اﻻﺣﺘﻜﺎك اﻟﺪاﺧﻠﻲ‬
a. Surface texture (rough or smooth): Resistance to displacement
b. Particle shape (angularity) ‫( اﻟﺘﺰوّي‬round, fractured, & cubical)
:‫ﻳﻘﻴﻢ ﻋﻦ ﻃﺮﻳﻖ‬
Angularity No. (0-10%) = % voids in round (≈33%) - % voids in any shape
‫( آﻠﻤﺎ آﺎن اﻟﺮآﺎم أﻓﻀﻞ‬10%) ‫وآﻠﻤﺎ اﻗﺘﺮﺑﺖ اﻟﻘﻴﻤﺔ ﻣﻦ‬
c. Gradation ‫( اﻟﺘﻮزﻳﻊ اﻟﺤﺒﻴﺒﻲ‬dense, gap, & open graded)
:‫ﻳﻘﻴﻢ ﻋﻦ ﻃﺮﻳﻖ‬
P
⎡d⎤
=⎢ ⎥
By Fuller (dense gradation) =
100 ⎣ D ⎦
1
2
Where:
D = diameter of max. size particle Æ (passing 100%); inch
d = size of opening for any sieve, inch
P = percent passing of that sieve.
:‫وﺗﺴﺘﻌﻤﻞ اﻟﻤﻨﺎﺧﻞ ﻓﻲ إﻳﺠﺎد ﺣﺠﻢ اﻟﺤﺒﻴﺒﺎت اﻟﻤﻄﻠﻮب وهﻲ آﻤﺎ ﻳﻠﻲ‬
2", 1.5", 1", 3/4", 1/2", 3/8", No.4, ….
.‫ ﻣﻌﻨﺎهﺎ ﺗﻮﺟﺪ أرﺑﻌﺔ ﺛﻘﻮب ﻓﻲ اﻷﻧﺞ اﻟﻤﺮﺑﻊ اﻟﻮاﺣﺪ‬No.4
:‫ ﻓﻨﺴﺘﺨﺮج ﺑﻘﻴﺔ اﻟﻨﺴﺐ ﻣﻦ اﻟﻘﺎﻧﻮن أﻋﻼﻩ وآﻨﺎ ﻳﺄﺗﻲ‬،1" ‫ إذا آﺎن اﻟﻤﻄﻠﻮب ﺗﺼﻤﻴﻢ ﺧﻠﻄﺔ ﺗﺤﻮي ﻋﻠﻰ رآﺎم أآﺒﺮ ﻗﻄﺮ ﻓﻴﻪ‬:‫ﻣﺜﺎل‬
04-1
Aggregate
Nov-2009
Lectures of Highway Engineering – Forth Stage
1"
1/2"
Æ
Æ
100%
3/8"
Æ
⎡ 3 "⎤
P=⎢ 8 ⎥
⎢ 1" ⎥
⎣
⎦
0.5
⎡ 1 "⎤
P = ⎢ 2 ⎥ *100 = 70%
⎢ 1" ⎥
⎣
⎦
0.5
*100 = 61%
.‫اﻟﺦ ﻣﻦ اﻟﻤﻨﺎﺧﻞ‬...
2) Durability (‫)اﻟﺪﻳﻤﻮﻣﺔ‬: The resistance to:
a. Crashing (‫)اﻟﻄﺤﻦ أو اﻟﺴﺤﻖ‬:
Crashing Value =
40 Tons
wt. of mat. pas sin g No.7
Original wt.
≤ 12% (≈ 8%)
(1/2" – 3/8")
‫ وﻣﺘﺒﻘﻲ‬1/2" ‫رآﺎم ﻣﺎر ﻣﻦ ﻣﻨﺨﻞ‬
3/8" ‫ﻋﻠﻰ اﻟﻤﻨﺨﻞ‬
b. Degradation (‫)اﻟﺘﻜﺴﺮ ﺑﺴﺒﺐ اﻟﺘﺄﺛﻴﺮ اﻟﻤﻴﻜﺎﻧﻴﻜﻲ‬:
% of wear by L. A. Operation, (‫)ﻃﺮﻳﻘﺔ ﻟﻮس أﻧﺠﻠﺲ‬
2.5kg (3/4"-1/2") + 2.5kg (1/2"-3/8") & Spheres (500 revolution)
Degradation =
wt. of mat. pas sin g No.12
≤ 30%
Original wt.
c. Disintegration (‫)اﻟﺘﻜﺴﺮ ﺑﺴﺒﺐ اﻟﺘﺄﺛﻴﺮ اﻟﻜﻴﻤﻴﺎﺋﻲ‬:
670 gm
330 gm
300 gm
1300 gm
(3/4" – 1/2")
(1/2" – 3/8")
(3/8" – No.4)
* Soundness
for 16-18 hours
& drying Cycle
By Na2SO4 (‫)آﺒﺮﻳﺘﺎت اﻟﺼﻮدﻳﻮم‬
≤ 12%
By MgSO4 (‫)آﺒﺮﻳﺘﺎت اﻟﻤﻐﻨﻴﺴﻴﻮم‬
≤ 18 %
3) Wet ability (‫)ﻗﺎﺑﻠﻴ ﺔ اﻟﺘﺮﻃﻴ ﺐ‬: adhesion with asphalt, or resistance to stripping of
asphalt film from aggregate in the presence of water.
a. Mechanical interlock: (‫)اﻟﺘﺄﺛﻴﺮ اﻟﻤﻴﻜﺎﻧﻴﻜﻲ‬
- Rough surface texture. (‫)ﺳﻄﺢ ﺧﺸﻦ‬
- Porous aggregate.
(‫ ﻟﻀﻤﺎن ﺗﺪاﺧﻞ اﻹﺳﻔﻠﺖ وﻋﺪم اﻧﻔﺼﺎﻟﻪ ﺑﺎﻟﻤﺎء‬،‫)ﻣﺴﺎﻣﻴﺔ ﺳﻄﺤﻴﺔ ﻋﺎﻟﻴﺔ وﻟﻜﻦ ﻏﻴﺮ ﻣﺆﺛﺮة ﻋﻠﻰ اﻟﻘﻮة‬
- No surface coating. (‫)إزاﻟﺔ اﻷﺗﺮﺑﺔ اﻟﻤﺤﻴﻄﺔ ﺑﺎﻟﺮآﺎم‬
04-2
Aggregate
Nov-2009
Lectures of Highway Engineering – Forth Stage
b. Chemical reactivity: (‫)اﻟﺘﺄﺛﻴﺮ اﻟﻜﻴﻤﻴﺎﺋﻲ‬
Basic minerals
(of aggregate)
(‫اﻟﻤﻮاد اﻷوﻟﻴﺔ )اﻟﺮآﺎم‬
+
Acidic portion
(of asphalt)
Æ
Compound not soluble in water
(‫ﻣﻮاد ﺣﺎﻣﻀﻴﺔ )ﻓﻲ اﻹﺳﻔﻠﺖ‬
‫ﻣﺮآﺐ ﻏﻴﺮ ذاﺋﺐ ﻓﻲ اﻟﻤﺎء‬
c. Interfacial tension: (‫)اﻟﺸﺪ اﻟﺴﻄﺤﻲ ﺑﺴﺒﺐ اﻟﺸﺤﻨﺎت‬
- Hydrophobic aggregate (water-hating) (‫)ﻏﻴﺮ ﻣﺄﻟﻮف ﻟﻠﻤﺎء‬
- Hydrophilic aggregate (water-loving) (‫)ﻳﺄﻟﻒ اﻟﻤﺎء‬
.‫ أﻏﻠﺐ اﻟﺮآﺎم اﻟﻌﺮاﻗﻲ ﻣﻦ اﻟﻨﻮع اﻟﺜﺎﻧﻲ )أﻟﻴﻒ ﻟﻠﻤﺎء( ﻟﺬﻟﻚ ﻳﺠﺐ ﻣﺮاﻋﺎة ذﻟﻚ‬.‫واﻟﻤﻔﻀﻞ ﻣﻨﻬﺎ ﻏﻴﺮ اﻟﻤﺄﻟﻮف ﻟﻠﻤﺎء‬
Aggregate combination (blending) & separation to meet Job Mix requirement:
‫أو ﻓﺼ ﻞ ﻟﺘ ﺪرﺟﺎت اﻟﺮآ ﺎم‬/‫ ﻟ ﺬﻟﻚ ﻧﺤﺘ ﺎج إﻟ ﻰ ﻋﻤﻠﻴ ﺔ دﻣ ﺞ و‬،‫اﻟﺮآ ﺎم اﻟﻄﺒﻴﻌ ﻲ ﻏﺎﻟﺒ ًﺎ ﻻ ﻳﻜ ﻮن ﺿ ﻤﻦ اﻟﻤﻮاﺻ ﻔﺎت اﻟﺨﺎﺻ ﺔ ﺑﺎﻟﺘ ﺪرج‬
:‫ﻟﻠﺤﺼﻮل ﻋﻠﻰ ﺗﺪرج ﻣﻘﺎرب ﻟﻤﻌﺎدﻟﺔ اﻟﺨﻠﻂ‬
1. Discarding the over size.
(‫)إﺑﻌﺎد اﻟﺤﺠﻮم اﻷآﺒﺮ ﻣﻦ اﻟﺤﺠﻢ اﻷﻗﺼﻰ ﻟﻠﺮآﺎم‬
2. Separating into two or more portions on selected proper sieve.
(‫)ﻓﺼﻞ اﻟﺮآﺎم إﻟﻰ ﺟﺰﺋﻴﻦ أو أآﺜﺮ ﻓﻲ ﻣﻨﻄﻘﺔ اﻟﺨﻠﻞ‬
3. Recombining using proper percentage for recombination with specification
requirement (mid-specification limits).
(‫)إﻋﺎدة دﻣﺞ اﻷﺟﺰاء ﺑﻨﺴﺐ ﻣﺌﻮﻳﺔ ﻣﻨﺎﺳﺒﺔ ﻟﺘﺘﻼﺋﻢ وﻣﻮاﺻﻔﺎت اﻟﺘﺪرج( )ﻣﻨﺘﺼﻒ اﻟﻤﻮاﺻﻔﺔ‬
4. Addition of fine materials (& Filler) if necessary.
(‫)إﺿﺎﻓﺔ رآﺎم ﻧﺎﻋﻢ )ﻣﻮاد ﻣﺎﻟﺌﺔ( ﻋﻨﺪ اﻟﺤﺎﺟﺔ‬
04-3
Aggregate
‫‪Nov-2009‬‬
‫‪Lectures of Highway Engineering – Forth Stage‬‬
‫‪Ex.:‬‬
‫‪Specifications‬‬
‫‪100‬‬
‫‪100‬‬
‫‪95 – 65‬‬
‫‪60 – 40‬‬
‫‪40 – 24‬‬
‫‪30 – 20‬‬
‫‪20 – 10‬‬
‫‪10 – 5‬‬
‫‪5–3‬‬
‫‪(% passing) Natural grading‬‬
‫‪100‬‬
‫‪90‬‬
‫‪80‬‬
‫‪60‬‬
‫‪40‬‬
‫‪30‬‬
‫‪20‬‬
‫‪10‬‬
‫‪5‬‬
‫‪Sieve size‬‬
‫"‪1‬‬
‫"‪3/4‬‬
‫"‪1/2‬‬
‫"‪3/8‬‬
‫‪No.4‬‬
‫‪No.10‬‬
‫‪No.40‬‬
‫‪No.80‬‬
‫‪No.200‬‬
‫‪Sol.:‬‬
‫ﻃﺮﻳﻘﺔ اﻟﺤﻞ‪:‬‬
‫‪ .1‬إزاﻟﺔ اﻟﺤﺠﻢ ﻓﻮق اﻟﺤﺠ ﻢ اﻷﻗﺼ ﻰ )‪ :(Discard Oversize‬ﻧﻼﺣ ﻆ أن اﻟﺤﺠ ﻢ اﻷﻗﺼ ﻰ ﻟﻠﺮآ ﺎم ﺿ ﻤﻦ اﻟﻤﻮاﺻ ﻔﺎت )"‪ (3/4‬ﻟ ﺬﻟﻚ‬
‫ﻳﺠﺐ إزاﻟﺔ اﻟﺤﺠﻮم ﺑﻴﻦ )"‪ (1"-3/4‬أي ﺟﻌﻞ اﻟﻤﺎر ﻣﻦ اﻟﻤﻨﺨﻞ )"‪ (100%) (3/4‬وﺗﺼﺤﻴﺢ ﺗﺪرج ﺑﺎﻗﻲ اﻟﻤﻨﺎﺧﻞ‪.‬‬
‫‪ .2‬ﺑﻌﺪ اﻟﻤﺮﺣﻠﺔ اﻷوﻟﻰ ﻧﺤﺪد ﺑﺪاﻳ ﺔ اﻟﺨﻠ ﻞ ﻓ ﻲ أي ﻣ ﻦ اﻟﻤﻨﺎﺧ ﻞ‪ ،‬وﻧﻼﺣ ﻆ أن ﻣﻨﻄﻘ ﺔ اﻟﺨﻠ ﻞ ﻣ ﻊ اﻟﻤﻮاﺻ ﻔﺎت ه ﻲ ﻋﻨ ﺪ اﻟﻤﻨﺨ ﻞ )"‪(3/8‬‬
‫وآﻤﻴ ﺔ اﻟﻤ ﺎر )‪ (67‬وه ﻲ ﻣﺘﺠ ﺎوزة ﻟﻠﻤﻮاﺻ ﻔﺔ )‪ ،(40-60‬ﻟ ﺬﻟﻚ ﻳ ﺘﻢ ﻓﺼ ﻞ اﻟﻤﻘ ﺎدﻳﺮ ﻋﻨ ﺪ اﻟﻤﻨﺨ ﻞ )"‪ (3/8‬واﻟ ﺬي ﻓﻴ ﻪ اﻟﺨﻠ ﻞ إﻟ ﻰ‬
‫ﻣﺠﻤﻮﻋﺘﻴﻦ ﺛﻢ ﻳﺘﻢ اﻟﻤﺰج ﺑﻨﺴﺐ ﺑﻤﺤﺎوﻟﺔ وﺧﻄﺄ ﻟﻠﻮﺻﻮل ﻟﻠﻨﺴﺐ اﻟﻤﻨﺎﺳﺒﺔ ﻟﺘﺼﺤﻴﺢ اﻟﺘﺪرج‪.‬‬
‫)‪(8‬‬
‫)‪(C‬‬
‫‪50% A‬‬
‫‪+‬‬
‫‪50% B‬‬
‫‪100‬‬
‫‪100‬‬
‫‪83‬‬
‫‪50‬‬
‫‪33‬‬
‫‪26‬‬
‫‪16‬‬
‫‪8‬‬
‫‪4.5‬‬
‫)‪(7‬‬
‫)‪(B‬‬
‫‪Portion‬‬
‫‪passing‬‬
‫"‪3/8‬‬
‫‪100‬‬
‫‪100‬‬
‫‪67‬‬
‫‪0‬‬
‫‪0‬‬
‫‪0‬‬
‫‪0‬‬
‫‪0‬‬
‫‪0‬‬
‫)‪(6‬‬
‫‪Percent‬‬
‫‪retained‬‬
‫)‪(5)-(4‬‬
‫‪0–0‬‬
‫‪0–0‬‬
‫‪11 – 33‬‬
‫‪33 – 100‬‬
‫)‪(5‬‬
‫)‪(A‬‬
‫)‪Step (2‬‬
‫‪Portion Passing‬‬
‫"‪3/8‬‬
‫‬‫‬‫‬‫‪100‬‬
‫‪(100/67)*45=67‬‬
‫‪(100/67)*34=51‬‬
‫‪(100/67)*22=33‬‬
‫‪(100/67)*11=16‬‬
‫‪(100/67)*6=9‬‬
‫)‪(4‬‬
‫)‪Step (1‬‬
‫‪Portion passing‬‬
‫"‪3/4‬‬
‫)‪(3‬‬
‫‪Specifications‬‬
‫)‪(2‬‬
‫)‪(% passing‬‬
‫‪Natural‬‬
‫‪grading‬‬
‫)‪(1‬‬
‫‪Sieve‬‬
‫‪size‬‬
‫‪100‬‬
‫‪100‬‬
‫‪(100/90)*80=89‬‬
‫‪(100/90)*60=67‬‬
‫‪(100/90)*40=45‬‬
‫‪(100/90)*30=34‬‬
‫‪(100/90)*20=22‬‬
‫‪(100/90)*10=11‬‬
‫‪(100/90)*5=6‬‬
‫‪100‬‬
‫‪100‬‬
‫‪95 – 65‬‬
‫‪60 – 40‬‬
‫‪40 – 24‬‬
‫‪30 – 20‬‬
‫‪20 – 10‬‬
‫‪10 – 5‬‬
‫‪5–3‬‬
‫‪100‬‬
‫‪90‬‬
‫‪80‬‬
‫‪60‬‬
‫‪40‬‬
‫‪30‬‬
‫‪20‬‬
‫‪10‬‬
‫‪5‬‬
‫"‪1‬‬
‫"‪3/4‬‬
‫"‪1/2‬‬
‫"‪3/8‬‬
‫‪No.4‬‬
‫‪No.10‬‬
‫‪No.40‬‬
‫‪No.80‬‬
‫‪No.200‬‬
‫ﻼ أي ان اﻟﺮآ ﺎم ﻻ ﻳﺤ ﻮﻳﻌﻠﻰ ﻣ ﻮاد ﻧﺎﻋﻤ ﺔ ﻣ ﻦ اﻟﺒﺪاﻳ ﺔ وﻻ ﻳﻤﻜ ﻦ ﺗﺼ ﺤﻴﺤﻪ ﺑﺈﻋ ﺎدة اﻟﺘﻮزﻳ ﻊ ﺑ ﻞ‬
‫إذا آﺎﻧﺖ ﻧﺴ ﺒﺔ اﻟﻤ ﺎﻟﺊ )‪ (1)= (4.5‬ﻣ ﺜ ً‬
‫ﺑﺈﺿﺎﻓﺔ )‪.(filler‬‬
‫)‪(5‬‬
‫‪97% C + 3% D‬‬
‫‪100‬‬
‫‪100‬‬
‫‪83.5‬‬
‫‪51.5‬‬
‫‪35‬‬
‫‪22.25‬‬
‫‪18.5‬‬
‫‪10.75‬‬
‫‪4‬‬
‫‪Aggregate‬‬
‫)‪(4‬‬
‫)‪(D‬‬
‫‪Filler‬‬
‫‪100‬‬
‫‪100‬‬
‫‪100‬‬
‫‪100‬‬
‫‪100‬‬
‫‪100‬‬
‫‪100‬‬
‫‪100‬‬
‫‪100‬‬
‫)‪(3‬‬
‫)‪(C‬‬
‫)‪(2‬‬
‫‪Specifications‬‬
‫)‪(1‬‬
‫‪Sieve size‬‬
‫‪100‬‬
‫‪100‬‬
‫‪83‬‬
‫‪50‬‬
‫‪33‬‬
‫‪26‬‬
‫‪16‬‬
‫‪8‬‬
‫‪1‬‬
‫‪100‬‬
‫‪100‬‬
‫‪95 – 65‬‬
‫‪60 – 40‬‬
‫‪40 – 24‬‬
‫‪30 – 20‬‬
‫‪20 – 10‬‬
‫‪10 – 5‬‬
‫‪5–3‬‬
‫"‪1‬‬
‫"‪3/4‬‬
‫"‪1/2‬‬
‫"‪3/8‬‬
‫‪No.4‬‬
‫‪No.10‬‬
‫‪No.40‬‬
‫‪No.80‬‬
‫‪No.200‬‬
‫‪04-4‬‬
Nov-2009
Lectures of Highway Engineering – Forth Stage
Ex.:
Sieve
1"
1/2"
No.4
No.10
No.40
No.80
No.200
Stock (A)
Passing
100
63
19
8
5
3
2
Stock (B)
Passing
Stock (C)
Passing
100
92
55
36
3
Specification
100
70 – 85
40 – 55
30 – 42
20 – 30
12 – 22
5 – 10
100
97
88
Sol.:
:‫ﻃﺮﻳﻘﺔ اﻟﺤﻞ‬
(No.200) ‫ وﻏﺎﻟﺒ ًﺎ ﻧﺒ ﺪأ ﺑﺎﻟﻨﺨ ﻞ‬،‫ﺗﻜﻮن ﻃﺮﻳﻘﺔ اﻟﺤﻞ ﺑﻄﺮﻳﻘﺔ اﻟﻤﺤﺎوﻟﺔ واﻟﺨﻄﺄ ﺑﻔﺮض ﻧﺴ ﺐ ﻣ ﺰج وﻣﻘﺎرﻧﺘﻬ ﺎ ﻣ ﻊ ﻣﻨﺘﺼ ﻒ اﻟﻤﻮاﺻ ﻔﺔ‬
(No.200) ‫( ﻧﺴ ﺒﺔ اﻟﻤ ﺎر ﻣ ﻦ اﻟﻤﻨﺨ ﻞ‬C) ‫ أي ﺑﻤ ﺎ أن ﻟﻠﻜﻮﻣ ﺔ‬،(Passing) ‫وﻧﻔﺮض ﻟﻪ ﻧﺴﺒﺔ ﺻﻐﻴﺮة ﻟﻠﻜﻮﻣ ﺔ ذا اﻟﻤﺤﺘ ﻮى اﻟﻌ ﺎﻟﻲ ﻣ ﻦ‬
(A, B) ‫( ﻓﻴﺠﺐ إﻋﻄﺎءهﺎ ﻧﺴﺒﺔ ﻗﻠﻴﻠﺔ وإﻋﻄﺎء ﻧﺴﺐ أآﺒﺮ ﻟﻠﻜﻮﻣﺘﻴﻦ‬5-10) ‫( واﻟﻤﻮاﺻﻔﺔ‬88) ‫ﻳﺴﺎوي‬
Sieve
1"
1/2"
No.4
No.10
No.40
No.80
No.200
‫ﻧﺴﺐ اﻟﻤﺰج‬
Stock (A)
Passing
100
63
19
8
5
3
2
65%
Stock (B)
Passing
100
92
55
36
3
30%
Stock (C)
Passing
Specification
100
70 – 85
40 – 55
30 – 42
20 – 30
12 – 22
5 – 10
100
97
88
5%
04-5
Mid
Specification
100
77.5
47.5
36
25
17
7.5
Passing %
Aggregate
100
76
47
38
25
18
7
Nov-2009
Lectures of Highway Engineering – Forth Stage
05-Asphalt Paving Mixture:
:‫ﻳﺠﺐ أن ﺗﺘﻮﻓﺮ ﻋﺪد ﻣﻦ اﻟﺨﻮاص اﻟﺘﻲ ﺗﺤﺪد آﻔﺎءة اﻷﺳﻔﻠﺖ‬
Function:
- Smooth riding quality surface. (‫)ﻧﻌﻮﻣﺔ ﺳﻄﺤﻴﺔ ﻟﻀﻤﺎن ﻧﻮﻋﻴﺔ ﺳﻴﺮ ﻣﻨﺎﺳﺒﺔ‬
- Safety. (‫)اﻷﻣﺎن‬
- Load carrying median. (‫)ﻳﻤﻜﻦ ﺗﺤﻤﻞ اﻷﺣﻤﺎل اﻟﻤﺮورﻳﺔ اﻟﻤﺴﻠﻄﺔ اﻟﻤﺘﻮﻗﻌﺔ‬
Note:
•
Batch plant: percentage depend on weight.
Continuous plant: percentage depend on volume.
•
Hot mix: after heating aggregate & asphalt.
Cold mix: mixing at normal temperature (emulsified asphalt).
•
Dense mix: % air voids ≤ 10%.
Open mix: % air voids > 10%.
Desirable properties:
1) Stability (‫)اﻟﺜﺒﺎت‬: resistance to permanent deformation.
(‫)ﻣﻘﺎوﻣﺔ اﻟﺨﻠﻴﻂ ﻟﻠﺘﺸﻮﻩ اﻟﺪاﺋﻤﻲ‬
Affected by:
• Frictional resistance (‫)اﻟﻤﻘﺎوﻣ ﺔ اﻟﻨﺎﺗﺠ ﺔ ﻣ ﻦ اﻻﺣﺘﻜ ﺎك‬: rough surface texture (of
aggregate), optimum asphalt content, & dense gradation with compaction.
(‫ ﺗﺪرج آﺜﻴﻒ ﻣﻊ اﻟﺮص‬،‫ ﻧﺴﺒﺔ اﻻﺳﻔﻠﺖ اﻟﻤﺜﻠﻰ‬،‫)ﺧﺸﻮﻧﺔ اﻟﺮآﺎم‬
• Cohesion (‫)اﻟﺘﻤﺎﺳ ﻚ‬: reology of asphalt, adhesion with aggregate, & surface area
of aggregate (filler 3-8%).
(‫)آﻠﻤﺎ ﻧﺰداد ﻣﺴﺎﺣﺔ اﻟﺮآﺎم ﻳﺰداد اﻟﺘﻼﺻﻖ ﺑﻴﻨﻪ وﺑﻴﻦ اﻷﺳﻔﻠﺖ ﻟﺬﻟﻚ ﻧﺴﺒﺔ اﻟﻤﺎﻟﺊ ﻣﻬﻤﺔ ﻓﻲ زﻳﺎدة اﻟﺜﺒﺎت‬
• Inertia of pavement: speed of vehicles, concentration of load, & axle load.
(‫ واﻟﺤﻤﻞ اﻟﻤﺤﻮري‬،‫ ﺗﺮآﻴﺰ اﻷﺣﻤﺎل‬،‫)ﺳﺮع اﻟﻤﺮآﺒﺎت‬
2) Durability (‫)اﻟﺪﻳﻤﻮﻣ ﺔ‬: resistance to weathering (air, water, & oil) & abrasive action
of traffic.
‫( وﻣﻘﺎﻣ ﺔ‬Stripping ‫ اﻟﻤ ﺎء واﻟﻤ ﻮاد اﻟﻨﻔﻄﻴ ﺔ ﺗﺴ ﺒﺐ ﻓﺼ ﻞ اﻟﻤ ﻮاد‬،Oxidation ‫)ﻣﻘﺎوﻣ ﺔ اﻟﺘﺠﻮﻳ ﺔ أواﻟﺘﻌﺮﻳ ﺔ )اﻟﻬ ﻮاء ﻳﺴ ﺒﺐ اﻟﺘﺄآﺴ ﺪ‬
(‫اﻟﺘﺄﺛﻴﺮ اﻻﺗﻼﻓﻲ ﻟﻠﺴﻴﺮ‬
05-1
Asphalt Paving Mixture
Nov-2009
Lectures of Highway Engineering – Forth Stage
Affected by:
• % of asphalt (‫)ﻧﺴﺒﺔ اﻻﺳﻔﻠﺖ‬
• Gradation (dense or open) (‫)اﻟﺘﺪرج‬
• Degree of compaction (‫)درﺟﺔ اﻟﺤﺪل‬
3) Flexibility (‫)اﻟﻤﺮوﻧﺔ‬: (fatigue resistance) ability to bend repeatedly without fracture.
(‫ ﻗﺎﺑﻠﻴﺔ اﻟﺘﻤﺪد ﻟﻤﺮات ﻣﺘﻌﺪدة ﺑﺪون ﺣﺪوث ﺗﻜﺴﺮ‬،‫)ﻣﻘﺎوﻣﺔ اﻟﻜﻠﻞ‬
4) Skid resistance (‫)ﻣﻘﺎوﻣﺔ اﻟﺘﺰﺣﻠﻖ‬: ability to provide safe coefficient of friction.
(‫)أﻣﻜﺎﻧﻴﺔ ﺗﻮﻓﻴﺮ ﻣﻌﺎﻣﻞ اﺣﺘﻜﺎك ﺁﻣﻦ‬
Affected by:
• % of asphalt. (‫)ﻧﺴﺒﺔ اﻻﺳﻔﻠﺖ‬
• Gradation. (‫)اﻟﺘﺪرج‬
5) Imperviousness (‫)ﻋﺪم اﻟﻨﻔﺎذﻳﺔ‬: (‫)اﻻﻧﻐﻼﻗﻴﺔ أو ﻋﺪم وﺟﻮد ﻣﺴﺎﻣﺎت‬
6) Workability (‫)ﻗﺎﺑﻠﻴ ﺔ اﻟﺘﺸ ﻐﻴﻞ‬: ability to provide smooth shaping of the finished
pavement.
Affected by:
• Balanced portion of materials (‫)أﺟﺰاء ﻣﺘﻨﺎﺳﺒﺔ ﻣﻦ اﻟﻤﻮاد‬
• Efficient equipments.
Job Mix formula:
1. Selection of aggregate quality & gradation with in specification limits.
(‫)اﺧﺘﻴﺎر اﻟﺮآﺎم ﻣﻦ اﻟﻨﺎﺣﻴﺔ اﻟﻨﻮﻋﻴﺔ واﻟﺘﺪرج ﺿﻤﻦ اﻟﻤﻮاﺻﻔﺎت اﻟﻘﻴﺎﺳﻴﺔ‬
2. Selection of asphalt cement grade.
((‫ وﻳﻜﻮن ﻟﻴﻦ ﻟﻀﻤﺎن ﻗﺎﺑﻠﻴﺔ اﻟﺘﺸﻐﻴﻞ واﻟﻤﻄﺎوﻋﺔ وﺻﻠﺐ ﻟﻤﻨﻊ اﻟﺘﺸﻮﻩ اﻟﺪاﺋﻤﻲ )اﻟﺜﺒﻮﺗﻴﺔ‬،‫)اﺧﺘﻴﺎر ﻧﻮﻋﻴﺔ اﻻﺳﻔﻠﺖ‬
3. Selection of optimum asphalt cement.
(‫ ﺗﻜﻮن آﻤﻴﺔ آﺎﻓﻴﺔ ﻟﻀﻤﺎن اﻟﺪﻳﻤﻮﻣﺔ واﻟﻤﻄﺎوﻋﺔ وﻻ ﺗﺆﺛﺮ ﻋﻠﻰ اﻟﺜﺒﻮﺗﻴﺔ واﻻﺣﺘﻜﺎك اﻟﺪاﺧﻠﻲ‬،‫)اﺧﺘﻴﺎر ﻧﺴﺒﺔ اﻻﺳﻔﻠﺖ اﻟﻤﺜﻠﻰ‬
05-2
Asphalt Paving Mixture
Nov-2009
Lectures of Highway Engineering – Forth Stage
Mix Design Methods:
1. Marshall method
2. Hveem method
3. Immersion – compression
4. Indirect tensile strength
5. Creep method
Marshall Method:
(Max. size of aggregate 1")
Stability: maximum load resistance of standard specimen (4" dia. & 2.5" height)
when tested in the direction of diameter, at 60oC at the rate of 2"/min.
(Stability ≥ 800 kg)
(60oC) ‫( ﻋﻨ ﺪ ﺗﺴ ﻠﻴﻄﻪ ﺑﺎﺗﺠ ﺎﻩ اﻟﻘﻄ ﺮ وﺑﺪرﺟ ﺔ ﺣ ﺮارة‬4"x2.5") ‫ وهﻲ ﻣﻘﺎوﻣﺔ أآﺒﺮ ﺣﻤﻞ ﻣﺴﻠﻂ ﻋﻠﻰ ﻧﻤﻮذج ﻗﻴﺎﺳﻲ‬:‫ﺛﺒﺎﺗﻴﺔ ﻣﺎرﺷﺎل‬
(2"/min.) ‫وﺑﻤﻌﺪل ﺗﺤﻤﻴﻞ‬
‫ ﻣﻠ ﺊ اﻟﻘﺎﻟ ﺐ ﺑ ﺎﻟﻤﺰﻳﺞ اﻟﺴ ﺎﺧﻦ ﺑﺪرﺟ ﺔ ﺣ ﺮارة اﻟﻤ ﺰج‬:‫ﻣﻠﺨ ﺺ ﻃﺮﻳﻘ ﺔ اﻟﻌﻤ ﻞ ﻟﻠﺘﺠﺮﺑ ﺔ‬
‫( ﺛﻢ ﺗﺘﻢ ﻋﻤﻠﻴﺔ اﻟﺮص وذﻟﻚ ﺑﻤﻄﺮﻗﺔ‬100-105oC) ‫( ﺛﻢ ﺗﺮآﻬﺎ ﻟﺘﺒﺮد ﻟﺪرﺟﺔ‬160oC)
Dial gage (1)
Stability
Dial gage (2)
Flexibility
4"
: ‫ﻗﻴﺎﺳﻴﺔ ﺑﻤﻌﺪل‬
75 blow/end (tire pressure = 200psi)
or 50 blow/end (tire pressure =100psi)
‫ ﺛ ﻢ ﺗﻔﺤ ﺺ‬،‫( ﻟﻀ ﻤﺎن زوال اﻟﺘﺸ ﻮهﺎت اﻟﻮﻗﺘﻴ ﺔ ﺑﺴ ﺒﺐ اﻟ ﺮص‬24hr) ‫ﺛ ﻢ ﺗﺘ ﺮك ﻟﻤ ﺪة‬
.‫ﺑﺠﻬﺎز ﻣﺎرﺷﺎل ﺑﺪرﺟﺔ ﺣﺮارة اﻟﻔﺤﺺ‬
Flexibility (Flow): the deformation (strain) corresponding to the max. load resistance
of the standard specimen. (2 – 4 mm)
Durability: density – voids analysis.
% of air voids (3 – 5)% or (3 - 7)% in total mix.
05-3
Asphalt Paving Mixture
Nov-2009
Lectures of Highway Engineering – Forth Stage
Density
(gm/m3)
‫ ﺛﺒﻮﺗﻴ ﺔ‬،‫ﺗﺮﺳﻢ اﻟﻌﻼﻗﺔ ﺑﻴﻦ ﻧﺴﺒﺔ اﻻﺳﻔﻠﺖ ﻓﻲ اﻟﻤﺰﻳﺞ ﻣﻊ اﻟﻌﻮاﻣﻞ )اﻟﻜﺜﺎﻓﺔ‬
.(‫ وﻧﺴﺒﺔ اﻟﻔﺠﻮات اﻟﻤﻤﻠﻮءة ﺑﺎﻻﺳﻔﻠﺖ‬،‫ ﻧﺴﺒﺔ اﻟﻔﺠﻮات‬،‫ اﻟﻤﺮوﻧﺔ‬،‫ﻣﺎرﺷﺎل‬
2
‫ﺛﻢ ﻳﺘﻢ اﺧﺘﻴﺎر اﻟﻨﺴﺒﺔ اﻟﻤﺜﻠﻰ ﻣﻦ اﻻﺳ ﻔﻠﺖ ﺑﺤﻴ ﺚ ﺗﺤﻘ ﻖ ﻗ ﻴﻢ ﻟﻬ ﺬﻩ اﻟﻌﻮاﻣ ﻞ‬
Stability
(kg)
‫ وذﻟ ﻚ ﺑﺈﻳﺠ ﺎد ﻧﺴ ﺒﺔ‬.‫ﺿﻤﻦ اﻟﻤﻮاﺻﻔﺎت اﻟﻘﻴﺎﺳ ﻴﺔ ﻟﻄﺒﻘ ﺔ اﻟﺘﺒﻠ ﻴﻂ اﻟﻤﻄﻠﻮﺑ ﺔ‬
:‫اﻻﺳﻔﻠﺖ اﻟﻤﻘﺎﺑﻠﺔ ﻟﻤﺎ ﻳﺄﺗﻲ‬
Flow
(mm)
(Max. Stability) ‫ أآﺒﺮ ﻗﻴﻤﺔ ﻟﻠﺜﺒﺎت‬.2
(‫( )ﻣﻌﺪل اﻟﻘﻴﻤﺔ‬5%) ‫ ﻋﻨﺪ ﻧﺴﺒﺔ ﻓﺠﻮات‬.3
5
1
(‫( )ﻣﻌﺪل اﻟﻘﻴﻤﺔ‬75%) ‫ ﻧﺴﺒﺔ اﻟﻔﺠﻮات ﻣﻤﻠﻮءة ﺑﺎﻻﺳﻔﻠﺖ‬.4
Voids in mix
(%)
8
Voids filled with asphalt
(%)
85
‫ ﻳﺴ ﻘﻂ اﻟﻤﻌ ﺪل ﻋﻠ ﻰ اﻟﻤﻨﺤﻨﻴ ﺎت‬،‫وﺑﺄﻳﺠ ﺎد ﻣﻌ ﺪل ﻟﻨﺴ ﺒﺔ اﻻﺳ ﻔﻠﺖ أﻋ ﻼﻩ‬
.‫ وﻳﺪﻗﻖ ﻣﻊ اﻟﻤﻮاﺻﻔﺔ‬،‫ﻻﻳﺠﺎد ﻗﻴﻤﺔ آﻞ ﻋﺎﻣﻞ ﻣﻦ اﻟﻌﻮاﻣﻞ‬
.‫وﺧﻮاص اﻟﺮآﺎم أو اﻻﺳﻔﻠﺖ‬
1000
600
(Max. Density) ‫ أآﺒﺮ ﻗﻴﻤﺔ ﻟﻠﻜﺜﺎﻓﺔ‬.1
‫إذا ﻟ ﻢ ﺗﻨﻄﺒ ﻖ أﺣ ﺪ اﻟﻤﻮاﺻ ﻔﺎت ﻓﻬﻨ ﺎك ﺧﻠ ﻞ ﻓ ﻲ ﻣﻮاﺻ ﻔﺎت وﺗﺤﻠﻴ ﻞ‬
2.4
2
65
4
5
6
Asphalt content by wt. of total
mix (%)
For surface course (wearing):
• % of asphalt (usually effective asphalt) = 4.5 – 6.5 % by wt. of total mix
• Stability at 60oC & 75 blows/end ≥ 800 kg
• Flow = 2 – 4 mm
• % air voids in total mix = 3 – 5 %
• % voids filled with asphalt = 70 – 85 %
• % voids in mineral aggregate V. M. A.% (min. =15%)
• Filler / Asphalt (max. = 1.4)
• Index of retained strength =
• Relative compaction =
comp. st. (Im mersion)
*100% ≥ 70%
comp. st. (Dry)
Field density
*100% ≥ 96%
Lab. density
Compaction of Pavement:
a) Rolling edges & joints: immediately after spreading (Tandem steel roller).
b) Break down rolling: as soon as the mix can bear roller (3-wheel roller).
c) Intermediate roller: while the mix is still plastic (kinematics roller).
d) Finish rolling: mix still warm to eliminate tire marks (steel roller).
Note: Smoothness: (Irregularities) ≤ 3mm/3m
3m
05-4
Asphalt Paving Mixture
Nov-2009
Lectures of Highway Engineering – Forth Stage
Analysis of Mixture (Mass-Volume Relationship):
‫ﻓﺮاﻏﺎت هﻮاﺋﻴﺔ‬
‫اﻻﺳﻔﻠﺖ اﻟﻔﻌﺎل‬
(‫)اﻟﻤﺤﻴﻂ ﺑﺎﻟﺮآﺎم‬
Aggregate particle coated
with asphalt, showing
absorbed asphalt, permeable
and impermeable porous
Zero
Air voids (air space)
Va
WS1
Binder
(Asphalt)
Effective asphalt
Gb
VS1
WS2
Absorbed Asphalt
VS2
WS
‫اﻻﺳﻔﻠﺖ اﻟﻤﻤﺘﺺ داﺧﻞ اﻟﻤﺴﺎﻣﺎت اﻟﻨﻔﺎذة ﻟﻠﺮآﺎم‬
‫اﻟﻔﺠﻮات اﻟﻤﺤﺼﻮرة ﺑﻴﻦ اﻟﺮآﺎم واﻻﺳﻔﻠﺖ‬
‫اﻟﺠﺰء اﻟﺼﻠﺐ ﻣﻦ اﻟﺮآﺎم‬
+
‫اﻟﻔﺠﻮات اﻟﺪاﺧﻠﻴﺔ اﻟﺼﻤﺎء‬
W
Vv
V
Permeable Porous
Wagg.
Solid Aggregate
+
Impermeable Porous
V3
V2
V1
Aggregate coated with
asphalt, showing air voids
Va = volume of air voids in total mix
Vs1 = volume of effective asphalt
Vs2 = volume of absorbed asphalt
V1 = apparent volume of aggregate
V2 = effective volume of aggregate
V3 = bulk volume of aggregate
V = total volume of mixture
Vv = voids of aggregate (Voids in mineral aggregate)
- Bulk GA = bulk specific gravity of combined aggregate =
=
WAgg.
V3
100
%course
%fine
%filler
+
+
Gs(course) Gs(file) Gs(filler)
Ex.:
50% (1"-No.4) Gs=2.6, 45%,
45% (No.4-No.200) Gs=2.65,
5% (No.200) Gs=3.15
Bulk GAgg. =
100
50
45
5
+
+
2.6 2.65 3.15
05-5
Asphalt Paving Mixture
Nov-2009
Lectures of Highway Engineering – Forth Stage
- PS = total % of asphalt (by wt. of total mix)
- PA = % of aggregate (by wt. of total mix)
PS + PA = 100% Æ PA = 100 - PS
- In void less mix Æ max. theoretical sp. gr. of mix
(max. Gm by testing in the lab (ASTM-2041)
max . Gm =
- Effective GA =
=
W
V − Va
WA
V2
100 − PS
(as sp. gr. of asphalt), where V2 = V-(Va+Vs1+Vs2),
100 PS
−
Gm Gs
Effective GA constant property (independent of asphalt content)
‫ وﻻﻳﺠ ﺎد‬،‫( ﻟﻨﺴ ﺒﺔ ﻣ ﻦ اﻻﺳ ﻔﻠﺖ ﻟﻨﻮﻋﻴ ﺔ رآ ﺎم واﺳ ﻔﻠﺖ‬Theoretical) (max. Gm) ‫ﻣ ﻦ ﺗﺠﺮﺑ ﺔ ﻣﺨﺘﺒﺮﻳ ﺔ ﻳﻤﻜ ﻦ أﻳﺠ ﺎد‬
(max. Gm) ‫( وﻧﻄﺒ ﻖ اﻟﻘ ﻮاﻧﻴﻦ اﻵﺗﻴ ﺔ ﻻﺳ ﺘﺨﺮاج ﻗ ﻴﻢ‬effective GA) ‫( ﻟﻨﺴ ﺐ أﺧ ﺮى ﻣ ﻦ اﻻﺳ ﻔﻠﺖ ﻳﻤﻜ ﻦ أﻳﺠ ﺎد‬max. Gm)
.‫( دون إﺟﺮاء ﺗﺠﺎرب أﺧﺮى‬Calculated)
- Actual Gm =
W
Wair
=
Wair − Wwater
V
Found by: Core from pavement, or compacted sp. gr. in lab
- Calculated max. Gm =
100
W
=
P
100 − PS
V − Va
S
+
Gs effective G A
- % air voids (in total mix) =
Va
max . Gm − actual Gm
*100% =
*100%
V
max . Gm
- % voids in mineral aggregate (V.M.A.%) =
Vv
actual Gm * PA
*100% = 100 −
bulk G A
V
Vv = V – V3, WS1 + WS2 = WS, WS + WA = W
- Absorbed asphalt (% by wt. of agg.) = P'S2 =
⎡
1
1
WS 2
*100%
WA
⎤
−
=⎢
⎥ * Gs *100%
⎣ bulk G A effective G A ⎦
V3 – V2 = VS2,
VS2Gs
,
WA
⎛ WA WA ⎞
⎟⎟
⎜⎜
,
⎝ V3 V2 ⎠
05-6
Asphalt Paving Mixture
Nov-2009
Lectures of Highway Engineering – Forth Stage
- Effective asphalt (% by wt. of total mix) = PS1 = PS −
P'S2 *PA
= PS – PS2
100
Where: PS2 = absorbed asphalt (% by wt. of total mix)
- % voids filled with asphalt =
=
VS1
*100%
Vv
actual Gm * PS1
*100%
actual Gm * PS1 + Gs * % air voids
Vv = Va + VS
Ex.: To prepare asphalt mixture as surface course, it is found the following:
a) For aggregate:
Sieve size:
% passing:
For course agg.
Gs = 2.64
For fine agg.
Gs = 2.67
For filler
Gs = 3.10
1"
100
No. 4
45
No. 200
5
b) For asphalt (40-50) Æ Gs = 1.04
c) For asphalt concrete contains 5% asphalt Æ max. Gm = 2.49
If the same above materials used to construct asphalt concrete layer with 5.7%
asphalt. The core from layer has Wair = 1200gm, & Wwater = 692gm. Check this layer?
Sol.:
Check: % air voids (3-5), V.M.A. = min. 15,
asphalt voids (70-85), effective asphalt (4.5-6.5)%, ‫اﻟﺘﻘﺮﻳﺐ ﻟﺜﻼث ﻣﺮاﺗﺐ‬
Bulk GA =
100
= 2.672
55
40
5
+
+
2.64 2.67 3.1
Effective GA =
100 − 5
= 2.687 (‫)ﻣﻘﺪرا ﺛﺎﺑﺖ ﺑﺘﻐﻴﺮ ﻧﺴﺒﺔ اﻻﺳﻔﻠﺖ‬
100
5
−
2.49 1.04
For the layer with asphalt = 5.7%
Actual Gm =
1200
= 2.362
1200 − 692
05-7
Asphalt Paving Mixture
Nov-2009
Lectures of Highway Engineering – Forth Stage
Calculated max Gm =
100
= 2.464
5.7 100 − 5.7
+
1.04
2.687
Check:
1) % V. M. A. = 100 −
2) % air voids =
2.362 * 94.3
= 16.6% ≥ 15% ∴OK
2.672
2.464 − 2.362
*100% = 4.1% (3 – 5)% ∴OK
2.464
3) absorbed asphalt (by wt. of agg.)
1
1 ⎤
−
= ⎡⎢
*1.04 *100% = 0.23%
⎣ 2.672 2.687 ⎥⎦
∴ effective asphalt concrete = PS1 = 5.7 −
0.23 * 94.3
= 5.48% (4.5-6.5)% ∴OK
100
4) % voids filled with asphalt
=
2.362 * 5.48
*100% = 75.2% (70 – 85)% ∴OK
2.362 * 5.48 + 1.04 * 4.1
05-8
Asphalt Paving Mixture
Nov-2009
Lectures of Highway Engineering – Forth Stage
06-Drainage:
Proper drainage is important to ensure high quality pavement. Moisture in the
subgrade and subbase layer can weaken these materials by:
1) Increasing pore water pressure.
2) Reducing the materials resistance to shear.
- Some soils expand when moist causing differential heaving.
- Moisture can cause stripping of aggregate.
Moisture Sources:
Rain water, runoff, and high ground water, which prevented by:
A) Surface Drainage:
By removing all water that is present on surface and shoulder, by these primary
means, to prevent water infiltration and accumulation:
1) Impermeable Mix:
Air voids in total mix <7%, by proper compaction and minor cracks in the mix
should be sealed.
2) Slop:
Cross slop =2% and using curb with gutter (in urban and suburban highways)
or road side ditches (in rural highway cut).
3) Grade:
Use grade ≥ 0.5% for curb with gutter or side ditches to allow flow to central
collection point.
B) Subsurface Drainage:
Is concerned with removing water, typically the result of high water table or
wet weather which can accumulate under the pavement structure by two chief means:
- Gravity flow: (in mix with air voids above 7%) and through cracks.
- Capillary rise: (in the fine grained soil).
06-1
Drainage
Nov-2009
Lectures of Highway Engineering – Forth Stage
1) Minimize water infiltration into the pavement structure: by providing proper road
side drainage and minimizing air voids in the mix.
2) Provide surface drainage: consist of three base elements:
- A permeable subbase to provide for rapid removal of water which enters the
pavement structure.
- A method of conveying the removed water, by using a base sloped towards a
drainage ditch.
- A filter layer (such as geotextile, graded aggregate) to prevent the migration of fines
into the permeable base from subgrade.
Asphalt or PCC
Shoulder
Base and/or subbase
Permeable base (subbsae)
grotextile or
graded agg.
Outlet
Collector pipe
06-2
Drainage
Nov-2009
Lectures of Highway Engineering – Forth Stage
07-Evaluation of Strength for Subgrade:
* C. B. R.: California Bearing Ratio, for subgrade in "Flexible Pavement".
C.B.R.0.1" =
C.B.R.0.2"
P0.1" (psi)
1000(psi)
Whichever is grater
P (psi)
= 0.2"
1500(psi)
* K: Modulus of subgrade reaction, for subgrade in "Rigid Pavement"
By Westagard: R = K * δ
Where: R = reaction (applied stress), δ = deflection
P
Pressure (P)
10psi
18" ϕ
P0.05"
24" ϕ
26" ϕ
28" ϕ
K
1
0.05"
30" ϕ
δ10psi
Subgrade
Deflection (δ)
‫ وﻳﻘ ﺮأ اﻟﺘﺸ ﻮﻩ وﻳﺮﺳ ﻢ‬،(‫ﺗﺠﺮى اﻟﺘﺠﺮﺑﺔ ﻣﻮﻗﻌﻴًﺎ ﻣﻦ ﺧﻼل ﺗﺤﻤﻴﻞ ﺻﻔﺎﺋﺢ ذات أﻗﻄﺎر ﻣﺨﺘﻠﻔﺔ )اﻟﻤﺒﻴﻨﺔ أﻋ ﻼﻩ‬
:‫ وهﻨﺎك ﻃﺮﻳﻘﺘﻴﻦ‬،(K) ‫ﻣﻨﺤﻨﻲ وﻣﻨﻪ ﻧﺴﺘﺨﺮج ﻗﻴﻤﺔ‬
As:
K (pci) =
P0.05"
0.05"
Or sometime: K =
10(psi)
δ10 psi
‫ وﻳﻤﻜ ﻦ اﺳ ﺘﺨﺪام أﻗﻄ ﺎر‬،‫ﻓﻲ ﺣﺎﻟﺔ ﻋﺪم اﻣﻜﺎﻧﻴﺔ اﺳﺘﺨﺪام ﺑﻌﺾ اﻟﺼﻔﺎﺋﺢ ﻓﻲ اﻟﺘﺠﺮﺑﺔ ﺑﺴ ﺒﺐ ﺿ ﻴﻖ اﻟﻤﺴ ﺎﺣﺔ‬
:‫أﺧﺮى وﺗﺼﺤﺢ اﻟﻨﺘﺎﺋﺞ‬
For the sheets & deflection:
Depend on K with 30" ϕ base plate
For K40"ϕ = 0.8 K30"ϕ
K20"ϕ = 1.5 K30"ϕ
07-1
Evaluation of Strength for Subgrade
Nov-2009
Lectures of Highway Engineering – Forth Stage
By AASHTO class.:
Clayey sand
A-7
Æ
K = 50 – 150 psi
Gravel
A-1
Æ
K = 400 – 500 psi
For soft subgrade:
(‫( ﻗﻠﻴﻠﺔ ﺟﺪًا )ﺗﺮﺑﺔ ﺿﻌﻴﻔﺔ‬K) ‫إذا آﺎﻧﺖ‬
Partial or full replacement with better soil, as granular material, with cohesive
soil (more frictional resistance), or by soil stabilization.
.‫ أو اﺳﺘﺨﺪام ﺗﻘﻨﻴﺎت ﺗﺜﺒﻴﺖ اﻟﺘﺮﺑﺔ‬،(‫اﺳﺘﺒﺪال ﺟﺰﺋﻲ او آﻠﻲ ﺑﺘﺮﺑﺔ أﻓﻀﻞ )ﺧﻠﻂ اﻟﺘﺮﺑﺔ اﻟﻀﻌﻴﻔﺔ ﺑﺘﺮﺑﺔ ﻗﻮﻳﺔ‬
07-2
Evaluation of Strength for Subgrade
Nov-2009
Lectures of Highway Engineering – Forth Stage
08-Thickness Design of Flexible Pavement:
By different methods [due to: methods pf traffic analysis, failure definition
(structural & users), evaluation of properties, & environmental effects].
1) AASHO (AASHTO) Guide method.
2) T. A. I. method (The asphalt institute method).
3) N. C. S. A. (National Crushed Stone Association).
AASHTO method:
D1
D2
D3
D4
D or h = f (Wt18, ρt, S, & R)
SN = f (S, R)
Note: h (for each layer) > max. size of agg. * 2
Surface
Leveling
Base
Subbase (C.B.R.)
Subgrade (C.B.R.)
Where:
a)
Wt18 = Equivalent (18kips) (≈8.2ton) single axle applications.
Wt18 = f (axle type, axle load magnitude, ρt, design life, & SN)
Wt18 = Σ T*A*F
Where:
T = Future trucks / Day / Direction = (Future ADT * %Truck * D.D)
A = Axle / Truck
F = Damage factor
b) ρt = Terminal Serviceability:
Lowest serviceability allowed at the end of design period before resurfacing or
reconstruction.
By:
Arbitrary scale (named present serviceability index: 5 for best riding quality, and 0
for worst)
ρt = 2.5 for main highway
ρt = 2.0 for secondary highway
08-1
Thickness Design of Flexible Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
c) S = Road bed support value
d) R = Regional factor
e) SN = Structural number:
Index number derived from analysis of traffic (Wt18), road bed support number
(S), regional factor (R) [from monograph], which may be converted to thickness of
various layers by using suitable layer coefficient.
SN4 = a1 D1+a1' D2+a2 D3+a3 D4
SN3 = a1 D1+a1' D2+a2 D3
SN2 = a1 D1+a1' D2
SN1 = a1 D1
Surface
Leveling
Base
Subbase
Subgrade
Subgrade
SN3 = a1 D1+a2 D2+a3 D3
SN2 = a1 D1+a2 D2
SN1 = a1 D1
D1 Æ a1
D2 Æ a1'
D3 Æ a2
D4 Æ a3
Surface
Base
Subbase
D1 Æ a1
D2 Æ a2
D3 Æ a3
Subgrade
Case (1) General
Case (2) Ideal Arrangement
(D1) ‫( ﻧﺠ ﺪ‬P.514) ‫( ﻣ ﻦ اﻟﻤﺨﻄ ﻂ‬a1)‫( و‬P.509) ‫( ﻣ ﻦ اﻟﻤﺨﻄﻄ ﺎت‬SN1) ‫( ﻧﺴﺘﺨﺮج‬D1) ‫( اﻟﻤﻄﻠﻮب‬SN1 = a1 D1) :‫ﻣﻼﺣﻈﺔ‬
.(0.5") ‫ﺑﺎﻻﻧﺞ وﻳﻘﺮب ﻷﻗﺮب ﻧﺼﻒ‬
For case (1) General:
a1 = Layer coefficient for Surface
D1 = Thickness of Surface (inch)
a2 = Layer coefficient for Base
D2 = Thickness of Base (inch)
a3 = Layer coefficient for Subbase
D3 = Thickness of Subbase (inch)
Design monographs and tables: Yoder (Table 4.9 P.164, 165), (Fig. 15.1 P.509), (Table 15.1
P.510), (Fig. 15.3 P.514, 515), (Fig. 15.5 P.516)
08-2
Thickness Design of Flexible Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
Ex.:
A main rural highway has been built or designed for (200) daily 18-kips single
axle load repetition. Regional factor (R) = 1.2 & the characteristics of pavement
materials as following:
Subgrade
Æ
C. B. R. = 5%
(Plastic clay)
Subbase
Æ
C. B. R. = 20%
(Sand-gravel)
Base
Æ
C. B. R. = 80%
(Crushed stone)
Surface
Æ
E = 4.3*105psi
(Asphalt concrete)
Sol.:
From graph (P.514, 515)
Surface
a1 = 0.42
(Modulus E = 4.3)
Base
a2 = 0.13
(C. B. R. = 80%)
Subbase
a3 = 0.095
(C. B. R. = 20%)
SN1 = a1 D1
Wt18 = 200
From graph (P.516)
‫( ﻟﻠﻄﺒﻘﺔ اﻟﺘﻲ ﻗﺒﻠﻬﺎ‬C. B. R.) ‫ﻗﻴﻢ‬
S1 (@ 80% C.B.R.) = 8.5
Æ
SN1 = 1.95
S2 (@ 20% C.B.R.) = 6.2
Æ
SN2 = 2.82
S3 (@ 5% C.B.R.) = 4
Æ
SN3 = 3.78
SN1 = a1 D1
1.95 = 0.42*D1
Æ
D1 = 4.64" use D1 = 5"
Æ
D2 = 5.54" use D2 = 6"
Æ
D3 = 9.47" use D3 = 9.5"
SN2 = a1 D1 + a2 D2
2.82 = 0.42*5 + 0.13*D2
SN3 = a1 D1 + a2 D2 + a3 D3
3.78 = 0.42*5 + 0.13*6 + 0.045*D3
08-3
Thickness Design of Flexible Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
H.W.:
Secondary highway, ADT (1994) = 400vph, truck = 40%, D. D. = 50%, annual
rate of traffic growth = 6%, design life = 20 years, wet (saturated road bed).
Truck type:
40Kips
13Kips
Materials
Properties
Asphalt concrete wearing course
M. S.
≥ 800 kg
Asphalt concrete leveling course
M. S.
≥ 700 kg
Crushed stone base
C. B. R.
80 %
Subbase
C. B. R.
30 %
Subgrade
C. B. R.
2%
Determine thickness of layers in (cm)
Note: let D1 = 8 cm
Ans.: D1 = 8cm (3"), D2 = 11cm (4.5"), D3 = 12cm (5"), D4 = 57cm (22.5")
1kg = 2.20462 lb
08-4
Thickness Design of Flexible Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
(Yoder, Fig. 15.3, P.515)
08-5
Thickness Design of Flexible Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
(Yoder, Fig. 15.3, P.515)
08-6
Thickness Design of Flexible Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
Regional Factor
(Yoder, Table 15.1, P.510)
Condition
Roadbed materials frozen to depth of 5in or more
Roadbed materials dry, summer and fall
Roadbed materials wet, spring thaw
R value
0.2 – 1.0
0.3 – 1.5
4.0 – 5.0
(Yoder, Fig. 15.5, P.516)
08-7
Thickness Design of Flexible Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
(Yoder, Fig. 15.5, P.517)
08-8
Thickness Design of Flexible Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
(Yoder, Fig. 15.1, P.509)
08-9
Thickness Design of Flexible Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
Table 4.9 AASHO Equivalence Factors – Flexible Pavement
(Yoder, P.164)
Single Axle, ρt = 2.0
Axle Load
(kips)
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
1
0.0002
0.002
0.01
0.03
0.08
0.16
0.32
0.59
1.00
1.61
2.49
3.71
5.36
7.54
10.38
14.00
18.55
24.20
31.14
39.57
2
0.0002
0.003
0.01
0.04
0.08
0.18
0.34
0.60
1.00
1.59
2.44
3.62
5.21
7.31
10.03
13.51
17.87
23.30
29.95
38.02
Structural Number, SN
3
4
0.0002
0.0002
0.002
0.002
0.01
0.01
0.04
0.03
0.09
0.08
0.19
0.18
0.35
0.35
0.61
0.61
1.00
1.00
1.56
1.55
2.35
2.31
3.43
3.33
4.88
4.68
6.78
6.42
9.24
8.65
12.37
11.46
16.30
14.97
21.16
19.28
27.12
24.55
34.34
30.92
5
0.0002
0.002
0.01
0.03
0.08
0.17
0.34
0.60
1.00
1.57
2.35
3.40
4.77
6.52
8.73
11.48
14.87
19.02
24.03
30.04
6
0.0002
0.002
0.01
0.03
0.08
0.17
0.33
0.60
1.00
1.60
2.41
3.51
4.96
6.83
9.17
12.17
15.63
19.93
25.10
31.25
Tandem Axle, ρt = 2.0
Axle Load
(kips)
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
1
0.01
0.01
0.02
0.04
0.07
0.10
0.16
0.23
0.32
0.45
0.61
0.81
1.06
1.38
1.76
2.22
2.77
3.42
4.20
5.10
2
0.01
0.02
0.03
0.05
0.08
0.12
0.17
0.24
0.34
0.46
0.62
0.82
1.07
1.38
1.75
2.19
2.73
3.36
4.11
4.98
Structural Number, SN
3
4
0.01
0.01
0.02
0.01
0.03
0.03
0.05
0.05
0.08
0.08
0.12
0.12
0.18
0.17
0.26
0.25
0.36
0.35
0.49
0.48
0.65
0.64
0.84
0.84
1.08
1.08
1.38
1.38
1.73
1.72
2.15
2.13
2.64
2.62
3.23
3.18
3.92
3.83
4.72
4.58
08-10
5
0.01
0.01
0.02
0.04
0.07
0.11
0.16
0.24
0.34
0.47
0.63
0.83
1.08
1.38
1.73
2.16
2.66
3.24
3.91
4.68
6
0.01
0.01
0.02
0.04
0.07
0.10
0.16
0.23
0.33
0.46
0.62
0.82
1.07
1.38
1.74
2.18
2.70
3.31
4.02
4.83
Thickness Design of Flexible Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
Table 4.9 (Continued)
(Yoder, P.165)
Single Axle, ρt = 2.5
Axle Load
(kips)
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
1
0.0004
0.003
0.01
0.03
0.08
0.17
0.33
0.59
1.00
2.61
2.48
3.69
5.33
7.49
10.31
13.90
18.41
24.02
30.90
39.26
2
0.0004
0.004
0.02
0.05
0.10
0.20
0.36
0.61
1.00
1.57
2.38
3.49
4.99
6.98
9.55
12.82
16.94
22.04
28.30
35.89
Structural Number, SN
3
4
0.0003
0.0002
0.004
0.004
0.02
0.01
0.05
0.04
0.12
0.10
0.23
0.21
0.40
0.39
0.65
0.65
1.00
1.00
1.49
1.47
2.17
2.09
3.09
2.89
4.31
3.91
5.90
5.21
7.94
6.83
10.52
8.85
13.74
11.34
17.73
14.38
22.61
18.06
28.51
22.50
5
0.0002
0.003
0.01
0.03
0.09
0.19
0.36
0.62
1.00
1.51
2.18
3.03
4.09
5.39
6.97
8.88
11.18
13.93
17.20
21.08
6
0.0002
0.002
0.01
0.03
0.08
0.18
0.34
0.61
1.00
1.55
2.30
3.27
4.48
5.98
7.79
9.95
12.51
15.50
18.98
23.04
Tandem Axle, ρt = 2.5
Axle Load
(kips)
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
1
0.01
0.02
0.03
0.04
0.07
0.11
0.16
0.23
0.33
0.45
0.61
0.81
1.06
1.38
1.75
2.21
2.76
3.41
4.18
5.08
2
0.01
0.02
0.04
0.07
0.10
0.14
0.20
0.27
0.37
0.49
0.65
0.84
1.08
1.38
1.73
2.16
2.67
3.27
3.98
4.80
Structural Number, SN
3
4
0.01
0.01
0.02
0.02
0.04
0.03
0.07
0.06
0.11
0.09
0.16
0.14
0.23
0.21
0.31
0.29
0.42
0.40
0.55
0.53
0.70
0.70
0.89
0.89
1.11
1.11
1.38
1.38
1.69
1.68
2.06
2.03
2.49
2.43
2.99
2.88
3.58
3.40
4.25
3.98
08-11
5
0.01
0.01
0.03
0.05
0.08
0.12
0.18
0.26
0.36
0.50
0.66
0.86
1.09
1.38
1.70
2.08
2.51
3.00
3.55
4.17
6
0.01
0.01
0.02
0.04
0.07
0.11
0.17
0.24
0.34
0.47
0.63
0.83
1.08
1.38
1.73
2.14
2.61
3.16
3.79
4.49
Thickness Design of Flexible Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
09-Rigid Pavement:
Joints
Concrete slab
Concrete slab
Base (or Subbase)
Function of Base (or Subbase):
1) Drainage purpose
Subgrade
2) Reduce the effect of subgrade volume change on concrete layer
3) Prevent pumping of fines through joints & edges
4) Increase "K" modulus of subgrade reaction
Rigid Pavement Characteristics:
- Can resist unlimited loading
- Minor defects are not reflected.
- More skid resistance, safe.
- More economical for same projects at certain location.
- Concrete layer is less thickness than other layers.
Rigid Pavement Types:
a) Plain concrete pavement:
1. No reinforcement except of using tie bars
(for longitudinal joints)
2. Closer spacing between contractions joint
(as transverse joints)
Longitudinal
Joints
Transverse
Joints
Inclined
Joints
3. Inclined joints may be used
(for better load transfer)
4. Very limited use
b) Simply reinforced concrete pavement:
1. Temperature (wire-mesh, B. R. C.) reinforcement between joints to control
cracking (close to the upper surface)
2. Dowel bars across transverse joints
09-1
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
3. Tie bars across longitudinal joints to control warping
4. Wider spacing between joints (from 3-6m to 12-14m)
Longitudinal
Joints
Transverse
Joints
5. Widely used
Section
c) Continuously reinforced concrete pavement:
1. No joints except some expansion joints & may be some contraction joints
2. Heavy reinforcement (≈ > 0.6% of cross sectional area)
3. High cost
4. Used in very-weak subgrade & high traffic load
d) Pre-stressed concrete pavement:
1. Fewer joints
2. More expensive
Type of Joints in Rigid Pavement:
1) Contraction joints: to relieve excessive tensile stress due to drop in temperature.
‫ واﻟﻨﺎﺗﺠﺔ ﻣﻦ اﻻﺣﺘﻜﺎك ﺑ ﻴﻦ اﻟﺒﻼﻃ ﺔ‬،‫ ﻟﻠﺘﺨﻠﺺ ﻣﻦ اﺟﻬﺎدات اﻟﺸﺪ اﻟﻨﺎﺗﺠﺔ ﻣﻦ اﻧﺨﻔﺎض درﺟﺔ اﻟﺤﺮارة‬:‫ﻣﻔﺎﺻﻞ اﻟﺸﺪ‬
.‫ واﻟﺘﻲ ﺗﺴﺒﺐ ﻓﺸﻞ اﻟﻄﺒﻘﺔ‬،(Subgrade) ‫واﻟﺘﺮﺑﺔ ﺗﺤﺘﻬﺎ‬
‫ﺗﻘﻠﺺ‬
‫ﻗﻮى اﺣﺘﻜﺎك‬
‫ واﻷﺧ ﺪود‬،‫ ﻟﻤﻨﻊ ﺗﺄآﺴﺪ ﺣﺪﻳﺪ اﻟﺘﺴﻠﻴﺢ وﺗﺄﺛﺮ ﻃﺒﻘﺔ اﻟﺘﺮﺑﺔ‬،‫وﺗﻌﺎﻟﺞ ﺑﻌﻤﻞ أﺧﺪود ﻳﻤﻸ ﺑﺎﻟﻤﺎﺳﺘﻚ ﻟﻤﻨﻊ اﻟﻤﻴﺎﻩ ﻣﻦ اﻟﻤﺮور‬
.‫ﻳﺼﻨﻊ ﻣﻨﻄﻘﺔ ﺿﻌﻴﻔﺔ ﻟﺘﺤﺪﻳﺪ ﻣﺴﺎر اﻟﻔﺸﻞ‬
3/8"
B.R.C.
d/4
d
d/2
Fixed
Dowel bars 1/2"-3/4" ϕ, 12-24" length,
& 12-18" spacing
(For load transfer)
Free
09-2
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
B. R. C. Design:
‫( ﻓ ﻲ اﻟﺠ ﺰء اﻷﻋﻠ ﻰ ﻣ ﻦ ﻃﺒﻘ ﺔ اﻟﺘﺒﻠ ﻴﻂ ﻟﻤﻘﺎوﻣ ﺔ اﺟﻬ ﺎدات اﻟﺸ ﺪ‬B.R.C.) ‫ﺗﻮﺿ ﻊ ﻃﺒﻘ ﺔ ﻣ ﻦ اﻟﺘﺴ ﻠﻴﺢ‬
‫ وﺗﻜ ﻮن ﻟﻄﺒﻘ ﺔ اﻟﺘﺒﻠ ﻴﻂ ﺑ ﻴﻦ اﻟﻤﻔﺎﺻ ﻞ )ﻋﻠ ﻰ ﺟ ﺎﻧﺒﻲ‬،‫( اﻟﻤﺘﻮﻟﺪة ﺑﺴﺒﺐ ﺗﻐﻴﺮ ﺗﺪرﺟﺎت اﻟﺤ ﺮارة‬Tensile stresses)
:‫ وأﺳﻠﻮب ﺣﺴﺎب آﻤﻴﺔ اﻟﺘﺴﻠﻴﺢ آﻤﺎ ﻳﺄﺗﻲ‬،(‫اﻷﺧﺪود‬
L
Edge
b
d
joint
joint
Edge
1ft
C
L = Allowable spacing for contraction joint (for longitudinal reinforcement), (ft)
b = Slab width, (ft)
C = Coefficient of friction (1 – 2 use 1.5)
γ = Unit wt. of concrete (pcf)
d = Slab thickness (ft)
Friction resistance = Allowable tensile strength
Friction resistance = Concrete tensile strength + Steel tensile strength
(L/2 * b * d)* γ * C = b * d * ftc + As * fs
For one unit of width use b =1ft
For safety assume concrete tensile strength (b * d * ftc) = 0
ftc = Allowable tensile strength of concrete ≈ 400 psi
fs = Allowable tensile strength of steel ≈ 25000 psi
As = Area of steel (in2/ft)
W=d*γ
where: W = Weight of 1ft2 of slab
L/2 * 1 * W * C = As * fs
As =
L*W *C
2FS
‫( ﺗﻜ ﻮن اﻟﻤﺴ ﺎﻓﺔ ﺑ ﻴﻦ‬L) ‫ أﻣ ﺎ ﻟﻠﺘﺴ ﻠﻴﺢ ﺑﺎﻻﺗﺠ ﺎﻩ اﻟﻌﺮﺿ ﻲ‬،‫( ﺗﻜﻮن اﻟﻤﺴﺎﻓﺔ ﺑﻴﻦ ﻣﻔﺼ ﻠﻴﻦ‬L) ‫ﻟﻠﺘﺴﻠﻴﺢ ﺑﺎﻻﺗﺠﺎﻩ اﻟﻄﻮﻟﻲ‬
.(b) ‫( أي‬edge to edge) ‫ﺣﺎﻓﺘﻲ اﻟﻄﺮﻳﻖ‬
09-3
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
2) Expansion Joints: provide a clear spacing along the depth to relieve excessive
compressive stresses due to rise in temperature.
‫ ﻓﺎﻟﻤﻌﺎﻟﺠﺔ ﺑﻌﻤﻞ أﺧﺪود أو ﻓﺮاغ ﻋﻠﻰ ﻋﻤﻖ ﻃﺒﻘ ﺔ اﻟﺘﺒﻠ ﻴﻂ ﻟﻤﻨ ﻊ‬،‫ ارﺗﻔﺎع درﺟﺔ اﻟﺤﺮارة ﺗﺴﺒﺐ اﻟﺘﻤﺪد‬:‫ﻣﻔﺎﺻﻞ اﻟﺘﻤﺪد‬
.‫إﺟﻬﺎدات اﻻﻧﻀﻐﺎط‬
3/4"
d/4
d
d/2
Fixed
Free
Dowel
bar
- Difficult in construction & maintenance
- Needed when casting in cold season, near structure, & for materials with high
coefficient of thermal expansion
- Contraction joints used as expansion joints
3) Warping joints: to relieve tensile stresses due to warping because of difference in
temperature between top and bottom of the slab (in night & day).
3/8"
T
Keyed
C
d/4
d
d/2
Fixed
Tie bar 1/2"ϕ,
30-36" length, &
24-30" spacing
Fixed
Night
C
T
Day
4) Construction joints: in some conditions.
.(‫ وﻳﺴﺘﺨﺪم ﻓﻲ ﺑﻌﺾ اﻟﺤﺎﻻت )ﻣﺜﻞ ﻧﻬﺎﻳﺔ وﺟﺒﺔ ﻋﻤﻞ وﺑﺪاﻳﺔ وﺟﺒﺔ أﺧﺮى‬:‫ﻣﻔﺼﻞ إﻧﺸﺎﺋﻲ‬
Fixed
Free
09-4
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
Thickness Design of Rigid Pavement:
Design methods:
1) PCA method (Portland Cement Association)
2) AASHO (AASHTO) guide method
1) PCA method: depends on fatigue analysis under repeated loading.
h = f (axle type, axle load magnitude, No. of repetitions, M. R. (fr), & K)
where:
h = thickness of concrete layer
Design steps:
a) Analysis of traffic:
Nact.: Actual No. of repetitions in 40-years period for each axle load.
Axles ≥ 16 kips – Single (‫ وﻣﻔﺮدة ﺗﻬﻤﻞ‬16 ‫)اﻟﻤﺤﺎور أﻗﻞ ﻣﻦ‬
Axles ≥ 30 kips – Tandem (‫ وﻣﺰدوﺟﺔ ﺗﻬﻤﻞ‬30 ‫)اﻟﻤﺤﺎور أﻗﻞ ﻣﻦ‬
Nact. = T * A * 40 * 365
Where:
T = Future truck per day per direction
A = No. of axles per truck for certain axle load
b) Correction for impact:
Static axle load * 1.2 = corrected (dynamic) axle load
c) M. R. (fr): Modulus of rupture (for third-point loading) (psi)
σ=
M.C
I
P
Where:
M=
b
d
b.d 3
P.L
d
, C= , I=
6
2
12
P.L
∴ M.R. = 2
b.d
L/3
09-5
L/3
L/3
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
M.R. = 8 − 10 f c
= 600 – 750 psi
Where: fc = Compression strength of concrete (psi)
d) K: Modulus of subgrade reaction
e) S: Actual load stress in pavement
Determine form design charts from either single or tandem axle, depend on:
- Corrected axle load
- K – value
- Suggested thickness of concrete layer "d"
f) SR: Stress ratio
SR =
S
, for each axle load
M.R.
g) Nall.: Allowable No. of repetitions of each axle load to account for fatigue in
concrete pavement (depend on stress ratio SR)
Note: Unlimited repetitions for SR = 0.5 or less Æ ∞ vehicles
h) F: Fatigue percentage
F=
N act.
*100% , for each axle load
N all.
i) Σ F < 100%, for correct assumption of "d" value
.‫" وإﻋﺎدة اﻟﺘﺼﻤﻴﻢ‬d" ‫( ﻓﻴﺠﺐ ﺗﻜﺒﻴﺮ‬ΣF ≥ 100%) ‫إذا آﺎﻧﺖ‬
،"d" ‫( ﻓﺘﺒﻘﻰ‬ΣF ≤ 85%) ‫إذا آﺎﻧﺖ‬
.‫( وإﻋﺎدة اﻟﺘﺼﻤﻴﻢ‬1-0.5") ‫" ﺑﻤﻘﺪار‬d" ‫( ﻓﺎﻟﺘﺼﻤﻴﻢ ﻏﻴﺮ اﻗﺘﺼﺎدي أي ﻧﻘﻠﻞ‬85%) ‫أﻣﺎ إذا آﺎﻧﺖ أﻗﻞ ﻣﻦ‬
Design monographs and tables: Yoder (Fig. 17.2, 17.3, P.604, 605), (Table 17.1, P.603)
09-6
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
Ex.:
T = 60 trucks/day/dir, K = 150 psi, & M. R. = 650 psi
Axle type
Axle load
A'
(kips)
(No. of axles/100 trucks)
Tandem
45
0.1
43
0.1
41
0.1
39
1.0
37
0.9
35
1.4
33
1.8
31
9.4
Single
21
3.2
19
5.4
17
6.1
Find concrete layer thickness "d" using P.C.A. method?
Sol.:
Nact. = 60*(A'/100)*40*365
…(1)
Corrected axle load = 1.2*axle load
…(2)
…(3)
S
650
N act.
F=
*100%
N all.
SR =
…(4)
Assume d = 7"
(1)
Axle
type
(2)
Axle
load
Tandem
45
43
41
39
37
35
33
31
21
19
17
Single
(3)
A'
(No. of axles/
100 trucks)
0.1
0.1
0.1
1.0
0.9
1.4
1.8
9.4
3.2
5.4
6.1
(4)
Nact.
(3)+eq.(1)
876
876
876
8760
7884
12250
15800
82400
28100
47400
53500
(5)
Corrected
axle load
(2)+eq.(2)
54
51.6
49.2
46.8
44.4
42.8
39.6
37.6
25.2
22.8
20.1
(6)
S
(7)
SR
(8)
Nall.
(9)
F (%)
Graph+(5)+K+d
435
415
410
390
375
350
325
310
350
325
290
(6)+eq.(3)
0.67
0.64
0.63
0.60
0.58
0.54
0.50
0.48
0.54
0.50
0.45
(7)+table
4500
11000
14000
32000
57000
180000
∞
∞
180000
∞
∞
ΣF
(4)+(8)+eq.(4)
19
8
6
27
14
7
0
0
15
0
0
96%
ΣF(%) = 96% < 100%
∴ d = 7" OK
09-7
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
2) AASHTO method:
d (slab thickness) = f (ρt, No. of Wt18, K, & working stresses in concrete)
a) ρt: Terminal level of serviceability
2.5 for main highway
2.0 for secondary highway
b) No. of Wt18: No. repetitions of 18-kips single axle load
as:
Wt18 = f (axle type, effective axle load, ρt, design life, assumed "d")
c) K: Modulus of subgrade reaction (pci)
d) Working stress in concrete = M. R. * 0.75
‫( ﻣﻦ اﻟﻤﻔﺮوض ﺗﻌﺎد ﻋﻤﻠﻴﺔ اﻟﺘﺼﻤﻴﻢ‬0.5") ‫ اﻟﻤﺴﺘﺨﺮﺟﺔ ﺑﻤﻘﺪار أﻗﻞ أو أآﺒﺮ ﻣﻦ‬d ‫إذا آﺎﻧﺖ‬
Design monographs and tables: Yoder (Fig. 17.4, 17.5, P.608), (Table 4.10, P.166, 167)
Ex.:
T = 60 trucks/day/dir, K = 150 psi, & M. R. = 650 psi
Axle type
Axle load
A'
(kips)
(No. of axles/100 trucks)
Tandem
45
0.1
43
0.1
41
0.1
39
1.0
37
0.9
35
1.4
33
1.8
31
9.4
Single
21
3.2
19
5.4
17
6.1
Find concrete layer thickness "d" using AASHTO method? (assume ρt = 2.5)
09-8
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
Sol.:
Nact. = 60*(A'/100)*40*365
…(1)
Corrected axle load = 1.2*axle load
…(2)
Assume d = 7"
(1)
Axle
type
(2)
Axle
load
Tandem
45
43
41
39
37
35
33
31
21
19
17
Single
(3)
A'
(No. of axles/
100 trucks)
0.1
0.1
0.1
1.0
0.9
1.4
1.8
9.4
3.2
5.4
6.1
(4)
Nact.
(3)+eq.(1)
(5)
Corrected axle load
(2)+eq.(2)
(6)
Equivalent factor
(5)+Table
(7)
No. of Wt18
(4)*(6)
876
876
876
8760
7884
12250
15800
82400
28100
47400
53500
54
51.6
49.2
46.8
44.4
42.8
39.6
37.6
25.2
22.8
20.1
10.61
9.23
7.85
6.47
5.21
4.16
3.296
2.588
3.796
2.56
1.65
ΣWt18
9294.4
8085.5
6876.6
56677.2
41075.6
50960
52076.8
213251.2
10666.6
12134.0
88596
559694 psi
ΣWt18 ≈ 560 ksi
Working stress = 0.75 * 650 = 487.5 psi
& K = 150 psi
From monograph:
d = 6.25" < dassumed (with more than 0.5") Not OK
check (redesign) with d = 6.5"
09-9
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
Table 17.1. Stress Ratios Allowable
Load Repetitions
Yoder, P.603
Stress
Allowable
Ratio
Repetition
SR
Nall (Veh.)
0.51
400,000
0.52
300,000
0.53
240,000
0.54
180,000
0.55
130,000
0.56
100,000
0.57
75,000
0.58
57,000
0.59
42,000
0.60
32,000
0.61
24,000
0.62
18,000
0.63
14,000
0.64
11,000
0.65
8,000
0.66
6,000
0.67
4,500
0.68
3,500
0.69
2,500
0.70
2,000
0.71
1,500
0.72
1,100
0.73
850
0.74
650
0.75
490
0.76
360
0.77
270
0.78
210
0.79
160
0.80
120
0.81
90
0.82
70
0.83
50
0.84
40
0.85
30
NOTE:
Unlimited Repetition for SR
= 0.5 or less
Figure 17.2, Yoder, P.604
d = (7 – 9) in
Charts and Tables for
Rigid Pavement Thickness
Design by PCA Method
Figure 17.3, Yoder, P.605
09-10
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
Table 4.10 AASHO Equivalence Factors – Rigid Pavement
(Yoder, P.166)
Single Axle, ρt = 2.0
Axle Load
(kips)
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
6
0.0002
0.002
0.01
0.03
0.09
0.19
0.35
0.61
1.00
1.55
2.32
3.37
4.76
6.59
8.92
11.87
15.55
20.07
25.56
32.18
7
0.0002
0.002
0.01
0.03
0.08
0.18
0.35
0.61
1.00
1.56
2.32
3.34
4.69
6.44
8.68
11.49
15.00
19.30
24.54
30.85
D – Slab Thickness (in)
8
9
0.0002
0.0002
0.002
0.002
0.01
0.01
0.03
0.03
0.08
0.08
0.18
0.18
0.34
0.34
0.60
0.60
1.00
1.00
1.57
1.58
2.35
2.38
3.40
3.47
4.77
4.88
6.52
6.70
8.74
8.98
11.51
11.82
14.95
15.30
19.16
19.53
24.26
24.63
30.41
30.75
10
0.0002
0.002
0.01
0.03
0.08
0.17
0.34
0.60
1.00
1.58
2.40
3.51
4.97
6.85
9.23
12.17
15.78
20.14
25.36
31.58
11
0.0002
0.002
0.01
0.03
0.08
0.17
0.34
0.60
1.00
1.59
2.41
3.53
5.02
6.94
9.39
12.44
16.18
20.71
26.14
32.57
10
0.01
0.03
0.05
0.08
0.13
0.20
0.30
0.44
0.62
0.85
1.14
1.51
1.96
2.51
3.17
3.95
4.87
5.95
7.20
8.63
11
0.01
0.03
0.05
0.08
0.13
0.20
0.30
0.44
0.62
0.85
1.14
1.51
1.97
2.52
3.19
3.98
4.93
6.03
7.31
8.79
Tandem Axle, ρt = 2.0
Axle Load
(kips)
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
6
0.01
0.03
0.05
0.09
0.14
0.22
0.32
0.45
0.63
0.85
1.13
1.48
1.91
2.42
3.04
3.79
4.67
5.72
6.94
8.36
7
0.01
0.03
0.05
0.08
0.14
0.21
0.31
0.45
0.64
0.85
1.13
1.45
1.90
2.41
3.02
3.74
4.59
5.59
6.76
8.12
D – Slab Thickness (in)
8
9
0.01
0.01
0.03
0.03
0.05
0.05
0.08
0.08
0.13
0.13
0.21
0.20
0.31
0.30
0.44
0.44
0.62
0.62
0.85
0.85
1.14
1.14
1.49
1.50
1.93
1.95
2.45
2.49
3.07
3.13
3.80
3.89
4.66
4.78
5.67
5.82
6.83
7.02
8.17
8.40
09-11
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
Table 4.10 (Continued)
(Yoder, P.167)
Single Axle, ρt = 2.5
Axle Load
(kips)
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
6
0.0002
0.003
0.01
0.04
0.10
0.20
0.38
0.63
1.00
1.51
2.21
3.16
4.41
6.05
8.16
10.81
14.12
18.20
23.15
29.11
7
0.0002
0.002
0.01
0.04
0.09
0.19
0.36
0.62
1.00
1.52
2.20
3.10
4.26
5.76
7.67
10.06
13.04
16.69
21.14
26.49
D – Slab Thickness (in)
8
9
0.0002
0.0002
0.002
0.002
0.01
0.01
0.03
0.03
0.08
0.08
0.18
0.18
0.35
0.34
0.61
0.60
1.00
1.00
1.55
1.57
2.28
2.34
3.23
3.36
4.42
4.67
5.92
6.29
7.79
8.28
10.10
10.70
12.94
13.62
16.41
17.12
20.61
21.31
25.65
26.29
10
0.0002
0.002
0.01
0.03
0.08
0.18
0.34
0.60
1.00
1.58
2.38
3.45
4.85
6.61
8.79
11.43
14.59
18.33
22.74
27.91
11
0.0002
0.002
0.01
0.03
0.08
0.17
0.34
0.60
1.00
1.58
2.40
3.50
4.95
6.81
9.14
11.99
15.43
19.52
24.31
29.90
10
0.01
0.03
0.05
0.08
0.13
0.20
0.30
0.44
0.62
0.85
1.14
1.50
1.95
2.48
3.12
3.87
4.74
5.75
6.90
8.21
11
0.01
0.03
0.05
0.08
0.13
0.20
0.30
0.44
0.62
0.85
1.14
1.51
1.96
2.51
3.16
3.94
4.86
5.92
7.14
8.55
Tandem Axle, ρt = 2.5
Axle Load
(kips)
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
6
0.01
0.03
0.06
0.10
0.16
0.23
0.34
0.48
0.64
0.85
1.11
1.43
1.82
2.29
2.85
3.52
4.32
5.26
6.36
7.64
7
0.01
0.03
0.05
0.09
0.14
0.22
0.32
0.46
0.64
0.85
1.12
1.44
1.82
2.27
2.80
3.42
4.16
5.01
6.01
7.16
D – Slab Thickness (in)
8
9
0.01
0.01
0.03
0.03
0.05
0.05
0.08
0.08
0.14
0.13
0.21
0.21
0.31
0.31
0.45
0.44
0.63
0.62
0.85
0.85
1.13
1.14
1.47
1.49
1.87
1.92
2.35
2.43
2.91
3.04
3.55
3.74
4.30
4.55
5.16
5.48
6.14
6.53
7.27
7.73
09-12
Rigid Pavement
Nov-2009
Lectures of Highway Engineering – Forth Stage
09-13
Rigid Pavement
Apr-10
Lectures of Highway Engineering – Forth Stage
10-The Effect of type and amount of Filler on Asphalt Paving Mix
First:
The role of the filler in the mix is very complex:
1. Serves as an inertic materials in the mix.
2. Serves as an active materials in the mix.
(due to its fineness and surface characteristics).
a. Specific Surface (S.S.) (m2/kg).
b. Surface Activity (S.A.) (Shape Factor).
c. Absorption.
* F/A (filler/Asphalt) ratio should be decreased as S.S. increases.
* S.A.: Capacity of filler particles to absorb AC.
And it increases as the irregularity increases (roughness and angularity)
* More absorption è decrease in free AC.
Second:
1. Behavior of filler/AC (mastic) and asphalt paving mixture can be explained by
physical-chemical properties of filler at the filler-AC interface.
2. H.L. (Hydrated Lime) have the highest geometric irregularity and high surface
activity è higher consistency (low penetration, high softening point, low
ductility) for mastics and higher strength in mix.
3. Rapid deterioration of mix occurred with non-active filler (after 4 days of
immersion at 60oC water) and H.L.
Exhibits a superior durability potential with mix sensitivity to the immersion
periods (as an active filler). [by E. Marshall St. Loss%, H.L. 5%, LSD (Limestone
Dust) (15%)]
4. The use of Portland cement as filler increase the fatigue life of the mix.
10-1
The Effect of type and amount of Filler on Asphalt Paving Mix
Apr-10
Lectures of Highway Engineering – Forth Stage
Third:
1. The type and amount of filler used in asphalt paving mix is are of the most
important factor that influence distress. (permanent deformation, low temp.
cracking, fatigue cracking, and moisture damage).
2. Limestone dust (L.D.) (3, 5, 7)%, Hydrated Lime (H.L.) (5%), Cement (C.I.) (5%).
- Marshall Stiffness = Stability / Flow (kg/mm) (Sp. 4"x2.5")
- Compressive Strength = Max load / Cross-Section Area (kg/cm2) (Sp. 4"x4")
- Indirect tensile strength =
2. Pu
(kg/cm2)
π.t.D
3. There is an optimum filler content for every type, satisfying most of asphalt paving
mixture requirements for (strength, durability, workability).
Shape Factor = 2.30 à
H.L. (sp=2.30) à S.S. = 750m2/kg
Shape Factor = 1.30 à
L.D. (sp=2.88) à S.S. = 260m2/kg
C.I. (sp=3.10)
10-2
The Effect of type and amount of Filler on Asphalt Paving Mix
Lectures of Highway Engineering – Forth Stage
10-3
Apr-10
The Effect of type and amount of Filler on Asphalt Paving Mix