Types of Pavements, Layers present in the pavements, Stresses on the rigid pavements, wheel load, repetitions etc.. and Indian Standard Method of design of Rigid Pavements.

1. DESIGN OF RIGIDDESIGN OF RIGID
PAVEMENTSPAVEMENTS
PART- IPART- I

2. COMPONENTS OF ROAD
G.L
SUBGRADE
EMBANKMENT
PAVEMENT
SHOULDERCARRIAGEWAY
ROAD WAY

3. PAVEMENTS
• Pavement : Pavement is a structure.
1. It consists of superimposed layers of
selected and processed materials.
2. It is placed on a Sub grade
3. It supports the applied traffic loads and
distributes them to the soil foundation.

4. ESSENTIAL REQUIEMENT OF PAVEMENTS
• 1) STRUCTURAL PERFORMANCE
– A PAVEMENT SHOULD BE
• (i) STRONG enough to resist the stresses imposed
on it and
• (ii) THICK enough to distribute the external loads
on the earthen subgrade.
• 2) FUNCTIONAL PERFORMANCE
– A PAVEMENT SHOULD HAVE
• (i) Riding quality,
• (ii) Surface friction for skid resistance,
• (iii) Low nice and
• (iv) Good geometrics.

5. TYPES OF PAVEMENTS
1)1) FLEXIBLE PAVEMENTS,FLEXIBLE PAVEMENTS,
2)2) RIGID PAVEMENTS,RIGID PAVEMENTS,
3)3) SEMI-RIGID PAVEMENTS,SEMI-RIGID PAVEMENTS,
4)4) COMPOSITE PAVEMENTS.COMPOSITE PAVEMENTS.

6. 1) FLEXIBLE PAVEMENTS
1. Consists THREE Layers.
2. It has low FLEXURAL strength.
3. Transfers the traffic loads by DISPERSION.
Wearing Course
SUB-BASE COURSE
BASE COURSE
Binding Course
SURFACE COURSE
SUB GRADE (FOUNDATION)

7. 1) FLEXIBLE PAVEMENTS

8. 2) RIGID PAVEMENTS
1. These consist of only TWO Layers.
2. Transfers the traffic loads by FLEXURE.
CC WEARING COURSE
SUB-BASE COURSE
SUB GRADE
Sub-base may be DLC/ PCC/ WMM/WBM

9. 2) RIGID PAVEMENTS

10. 3) SEMI-RIGID PAVEMENTS
• Surface course is FLEXIBLE.
• Base/ Sub-base is RIGID.
BITUMINOUS WEARING COURSE
RIGID BASE COURSE
SUB GRADE
Rigid Base may be DLC/ Lime-fly ash/ soil-cement concretes

11. 4) COMPOSITE PAVEMENTS
• These Pavements comprises of multiple,
structural layers of different, heterogeneous,
composition.
Ex:: Brick sandwiched pavement, which
consists CC pavement layers at bottom and
top duly sandwiching brick layer.

12. WHAT IS RIGID PAVEMENT ?
1)The load carrying capacity is mainly due to the rigidity and
high modulus of elasticity of the slab itself, i.e., slab action
2) The strength of rigid pavement is mainly of FLEXURAL
strength ( beam strength).
3) The stresses developed due to different loads are BENDING
stresses.
4) The design of CC Pavement is based on its Flexural
Strength not on Compressive strength.

13. TYPES OF RIGID PAVEMEDNTS
• 1) JOINTED PLAIN CONCRETE PAVEMENTS –
JPCP.
• 2) JOINTED REINFORCED CONCRETE
PAVEMENTS – JRCP.
• 3) CONTINUOUSLY REINFORCED CONCRETE
PAVEMENTS – CRCP.

14. 1) JOINTED PLAIN CONCRETE PAVEMENTS
• a) Characterized by short joint spacing ( 4.50 to 5.00 m).
• b) No temperature reinforcement is provided.

15. 2) JOINTED REINFORCED CONCRETE PAVEMENTS
• a) Characterized by LONG joint spacing ( 9.00 to 30.00 m).
• b) Nominal temperature reinforcement is provided.

16. 3) CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS
• a) Theoretically no joints,
• b) Designed temperature reinforcement is provided to control the
concrete from Shrinkage .

17. DESIGNE PRINCIPLE
• Design is a process of
adjusting factors that we can control
in order to
accommodate factors that we cannot control
and achieve
the parameters and performance that we want.

18. DESIGNE of
PLAIN JOINTED CEMENT CONCRETE PAVEMENT
Factors that we can control
1. Type of Cement Concrete Pavement (Grade),
2. Thickness of C.C. Pavement,
3. Type and thickness of supporting courses,
4. Spacing of Joints.
Factors that we have to accommodate (that we cannot control)
1. Wheel loads,
2. Design Traffic in the Design Period,
3. Temperature differential,
4. Properties of Concrete ( E, u, a ),
5. Properties of Subgrade.
Parameters and performances to be achieved are
1. The stresses developed should be less than the strength
2. The Cumulative Fatigue Damage should be less than 1.0.

19. DESIGN CODES
• Commercial traffic = Vehicle with LADEN weight exceeding 3.0 T.
• CVPD = Commercial Vehicles Per Day.
In case CVPD <= 150 ( on Rural Roads )
IRC:SP:62, GUIDELINES FOR THE DESIGN AND CONSTRUCTION OF CEMENT
CONCRETE PAVEMENTS FOR RURAL ROADS.
In case CVPD > 150 ( other than Rural Roads )
IRC:58-2002, GUIDELINES FOR THE DESIGN OF PLAIN JOINTED RIGID
PAVEMENT FOR HIGHWAYS.
________________________________
In this session we deal with IRC:58-2002

20. IRC:58-2002 DESIGN PRINCIPLE
DESIGN ::The basic design of SLAB is done with
98 % Axle Load considering STRESSES
developed from loads.
CHECK :: The design there after checked for
FATIGUE CONSUMPTION for Higher axle loads.

21. WHEEL LOADS SURVEY
• LEGAL AXLE LOAD LIMIT IN INDIA
• 10.2 t – for SINGLE AXLES,
• 19.0 T – for TANDEM AXLES
• 24.0 T – for TRIDEM ACLES
In designing PAVEMENT thickness axle loads plays vital Role.
Higher Axle Loads induces very high stresses.
Axle load survey to be conducted in which
6, 8, 10, 12, 14, 16, 18, 20, 22 and 24 T for Single Axles
12, 16, 20, 24, 28, 32, 36, 40, 42 and 44 T for Tandem Axles

22. TYRE PRESSURD
• Tyre pressure varies from 0.70 to 1.0 MPa
• For Design purpose Tyre pressure = 0.80 MPa

23. LOAD SAFETY FACTOR-LDF
In order to take care of
– unpredicted heavy truck loads and
– high volume of truck traffic
The Axle loads should be increased by multiplying with L.S.F
L.S.F. = 1.2 for Express ways and National Highways.
L.S.F. = 1.1 for Lesser important Roads.
L.S.F. = 1.0 for Residential and other street roads.

24. DESIGN PERIOD
The life span of Cement Concrete Pavement is 30 Years.
Design Period = 30 Years
for the Roads with predictable traffic.
Design Period = 20 Years
for the Roads with unpredictable traffic
and Low Volume Roads
.

25. DESIGN TRAFFIC
The cumulative number of repetitions of Axles
during the design period.
( ){ }
r
rA
C
n
11*365 −+
=
A = Initial number of AXLES PER DAY in the year when the road is
operational.
r = Annual rate of growth of commercial traffic ( Laden weight >3 T)
r = 0.075 (or 7.50 %)
n = Design period in years = 30/ 20 years.

26. DESIGN TRAFFIC
Flexural STRESS caused by Axle load
= Maximum When the tyre imprint is
tangential to the LONGITUDINAL EDGE.
TWO LANE
Design traffic = 25 % of Total Two way
commercial vehicles.
FOUR LANE/ MULTI LANE
Design traffic = 25 % of Total traffic in the
direction of predominant traffic.
HOUL ROADS IN MINE AREAS
Design traffic is arrived with suitable
adjustment.
The DESIGN TRAFFIC is used to calculate
FATIGUE FAILURE.

27. TEMPERATURE DIFFERENTIAL
Temperature differential between
the
TOP and BOTTOM
of concrete pavements causes the
concrete slab to
WARP
giving rise to
STRESS

28. CHARACTERISTIC OF SUBGRADE
• SUB GRADE (Foundation)
– The strength of Subgrade is expressed in terms of
Modulus of subgrade reaction, k.
– MODULUS OF SUBGRADE REACTION:
• 1) It is a pressure per unit deflection of foundation
(Subgrade).
• 2) UNIT = Pressure/ Deflection
= kg/sq cm/cm = kg/cucm.
• 3) It is determined by plate bearing test.
• 4) The limiting design deflection for C.C. Pavement is 1.25
mm.
• 5) The k- value of subgrade is the pressure sustained at this
deflection.

29. Soaked CBR
value in %
2 3 4 5 7 10 15 20 50 100
CHARACTERISTIC OF SUBGRADE
APPROXIMATE K-VALUE CORRESPONDING TO
CBR VALUES FOR HOMOGENOUS SOILS
K- value
(kg/sqcm/cm)
2.1 2.8 3.5 4.2 4.8 5.5 6.2 6.9 14 22.2
If k-value of subgrade is less than 6.0 kg/sqcm/cm,
the Cement Concrete Pavement
should not be laid directly over the subgrade.
Sub-base to provided to over Subgrade.

30. CHARACTERISTIC OF SUB-BASE
• SUB-BASE MAY BE ANY OR SOME OF
• a) Granular material (WBM/ WMM) ,
• b) Stabilized Soil/ Cement treated Granular material
• c) Dry lean concrete (Semi-rigid Material )
The code strongly recommends Dry lean concrete sub-base
for modern concrete pavements.
• Note:- All the above Sub-bases augment the
k-value of Sub grade.

31. SUB-BASE with GRANULAR MATERIAL
• Granular Material
a) Layers of Water Bound Macadam (WBM) or
Wet Mix Macadam.
b) Well graded granular material, like, natural
gravel, crushed slag, crushed concrete, brick
metal, literate, kantar etc.,
c) Well-graded soil aggregate mixture.

32. SUB-BASE with GRANULAR MATERIAL
K- VALUES OVER GRANULAR SUB-BASE
K-value of
subgrade
(kg/sqcm/cm)
Effective k(kg/sqcm/cm) over
untreated granular layer sub-
base of thickness in cm
15 22.5 30
2.8 3.9 4.4 5.3
5.6 6.3 7.5 5.3
8.4 9.2 10.2 11.9
The thickness of sub-base should not be less than 150 mm

33. SUB-BASE with STABLISED SOIL
• Stablised/ Cement treated Sub-base
Local soil or murram stablised with
• LIME or
• LIME-FLY ASH or
• CEMENT.
7-day unconfined compressive strength of the
treated/ stablised granular soil should a
minimum of 2.1 MPa.

34. SUB-BASE with STABLISED SOIL
K- VALUES OVER CEMENT TREATED SUB-BASE
K-value of
subgrade
(kg/sqcm/cm)
Effective k (kg/sqcm/cm) over
cement untreated granular layer
sub-base of thickness in cm
10 15 20
2.8 7.6 10.8 24.1
5.6 12.7 17.3 22.5
The thickness of sub-base should not be less than 150 mm

35. SUB-BASE with Dry lean concrete (Semi-rigid Material )
• Semi-rigid Material.
a) Lime-burnt clay puzzolana concrete. The 28 day
compressive strength should be 40-50 kg/ sqcm.
b) Lime-fly ash concrete or
c) Dry Lean Cement Concrete. DLC should have a minimum
compressive strength of 7 MPa at 7 days.
The code strongly recommends Dry lean concrete sub-base
for modern concrete pavements with heavy traffic.

36. SUB-BASE with Dry lean concrete (Semi-rigid Material )
K- VALUES OVER DRY LEAN CONCRETE SUB-BASE
k-value of subgrade
(kg/sqcm/cm) 2.1 2.8 4.2 4.8 5.5 6.2
Effective k over 100 mm
DLC (kg/sqcm/cm) 5.6 9.7 16.6 20.8 27.8 38.9
Effective k over 150 mm
DLC (kg/sqcm/cm) 9.7 13.8 20.8 27.7 41.7 --
The code considers the k-values of 6 - 30 kg/cucm

37. SEPPARATION MEMBRANE
Foundation layer below
concrete slabs should be
smooth surface to reduce
the inter layer friction.
A separation membrane of
minimum thickness 125
micron (0.125 mm)
ploythene is
recommended to reduce
friction.

38. DRAINAGE LAYER
The subgrade should be protected from softening and erosion.
This is done in any of following ways according to nature of
subgrade.
a) FILTER LAYER :: to prevent the subgrade from wetting so
that the CBR value not effected.
b) BLANKET LAYER :: of 225 mm thick in case of clayey
subgrade.
c) DRAINAGE LAYER :: to facilitate quick disposal of water
The drainage layer may be GSB or WMM or SAND BED.

39. CHARECTERISTICS OF CONCRETE
The important properties of concrete to be considered
in designing of Cement Concrete Pavement.
a) DESIGN STRENGTH,
b) MODULUS OF ELASTICITY,
c) POISSON’S RATIO,
d) COEFFICIENT OF THERMAL EXPANSION and
e) FATIGUE BEHAVIOUR OF CONCRETE.

40. DESIGN STRENGTH OF CONCRETE
The Concrete
Pavements fail
due to bending
stresses. Hence
the design of
concrete
pavements is
based on
FLEXURAL
STRENGTH
(MODULUS OF
RUPTURE) of
concrete.

41. DESIGN STRENGTH OF CONCRETE
Flexural strength
should be
determined by
modulus of rupture
tests under third
point loading.
The size of beam be
150x15x70 cm

42. DESIGN STRENGTH OF CONCRETE
Flexural strength of Plain concrete can be obtained
from the characteristic compressive cube
strength of concrete.
The formula is
ckcr ff *7.0=
Flexural strength in N/sq.mm
characteristic compressive cube
strength of concrete.
=crf
=ckf

43. MODULUS OF ELASTICITY and POISSON’S RATIO
Modulus of elasticity of concrete, E
E = Experimentally determined value or
= 300000 kg/ sq.cm.
Poisson’s ratio, u = 0.15
Coefficient of thermal expansion, a
a = 1/100000 per degree centigrade

44. FATIGUE BEHAVIOUR OF CEMENT CONCRETE
Due to repeated application of of FLEXURAL STRESSES by traffic
loads, a progressive damage takes place in the cement concrete
slab in the form of gradual development of micro-cracks.
When the applied stresses in terms of flexural stress is high, the
micro-cracks are high.
STRESS RATIO , SR
SR = Flexural stress due to LOAD /
Flexural strength of CONCRETE
Higher the STRESS RATIO,
Lower the number of REPETITIONS

45. FATIGUE BEHAVIOUR OF CEMENT CONCRETE
Fatigue N is measured in terms of NUMBER OF
REPETITION of LOAD.
Stress Ratio- SR Allowable Repetitions- N
Less than 0.45 Un limited
0.45 – 0.55
268.3
4325.0
2577.4






−SR
Greater than 0.55 [ ] 0828.0
)9718.0(
10
SR−

46. THANK YOUTHANK YOU
continued in Partcontinued in Part
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