This document summarizes the theory of flexible pavement construction presented by four civil engineering students at AKS University Satna. It defines flexible pavement as layers consisting of soil subgrade, subbase course, base course, and surface course that distribute vehicle loads through particle contact down to the subgrade. Common tests used to evaluate the soil subgrade strength are the group index method, California bearing ratio method, and triaxial compression test. The group index method assigns a rating from 0 to 20 based on soil properties, with higher values indicating a weaker subgrade requiring thicker pavement. The California bearing ratio method determines pavement thickness based on the subgrade strength and intended wheel loads.
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1. “
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AKS UNIVERSITY SATNA
DEPT. OF CIVIL ENGINEERING 2022
CONSTRUCTION OF FLEXIBLE PAVEMENT
Guide by : Mrs. Shraddha Pandey
(Assistant Professor)
Department of Civil Engineering
2. THEORY OF
FLEXIBLE PAVEMENT
Presented by :
Ritik Mishra ( B2055R14401010)
Arunendra Pratap Singh Patel ( B2055R14401009)
Anand Kumar Ahirwar ( B2055R14401011)
Moinuddin Shah (B1955R10101029)
3. WHAT IS PAVEMENT ?
• Pavement is one type of hard surface made from durable surface material laid down
on an area that is intended to carry vehicular or foot traffic.
• A structure consisting of superimposed layers of processed materials above the
natural soil sub-grade , whose primary function is to distribute the applied
vehicle loads to the sub – grade.
5. FLEXIBLE PAVEMENT :
• Flexible pavement are named flexible because they transfer the load applied on it
through particle contact by distribution it through particle contact by distributed
from top to bottom up to subgrade .
• Flexible pavement are those which on a whole have low or negligible flexural
strength and rather flexible in their structural action under load .
6.
7. RIGID PAVEMENT
Rigid pavements are constructed of portland cement concrete slabs
resting on a prepared subbase of granular material or directly on a
granular subgrade. Load is transmitted through the slabs to the
underlying subgrade by flexure of the slabs.
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10. FLEXIBLE PAVEMENT CONSIST OF THE FOLLOWING
COMPONENTS:
Soil sub grade
Sub base course
Base course
Surface course
11. COMMON STRENGTH TESTS USED FOR
EVALUATION OF SOIL SUB GRADE ARE:
Group index method (GI)
California Bearing Ratio method (CBR)
Modified CBR method
Triaxial compression test
12. GROUP INDEX METHOD (GI) :
• The thickness requirement of pavements on the basis of group index value.
• In this method soil depending on the percentage , fineness, liquid limit and
plasticity index.
• The higher value of GI represents the weaker soil subgrade, the greater values be
the thickness of pavement.
• The GI values of soil vary from 0 to 20.
13. LIMITATION:
• This method does not consider the strength characteristic of sub grade soil.
• quality of pavement is not considered, some thickness is required , even better
quality material is used.
FORMULA:
GI = 0.2a + 0.005ac + 0.01bd
a = percentage of material passing through IS 200 (0.075mm) sieve, is more than 35 and less than 75 (0 to 40)
b = percentage of material passing through IS 200 (0.075mm) sieve, is more than 15 and less than 55 (0 to 40)
c = liquid limit more than 40 and less than 60 (0 to 20)
d = plasticity index more than 10 and less than 30 (0 to 20)
14.
15. CALIFORNIA BEARING RATIO METHOD (CBR):
• This method is based on the strength parameters of subgrade soil and subsequent pavement material.
• Thickness of subbase
Thickness of subbase= Total thickness – Thickness over subgrade
Thickness of base = Thickness of subbase – thickness over base
FORMULA :
T(cm)=
𝟏.𝟕𝟓𝒑
𝒄𝒃𝒓
− 𝑷/𝝅𝒑
P= wheel load in kg , p= tyre presser or contact presser in kg /cm 2, P/pπ=P/π(P/A) = A/π= πa2/π= a2
A= contact presser
a= radius of contact area
• This formula is more appropriate for the CBR value of subgrade. Less than 12%
16. LIMITATION:
• This CBR method gives the total thickness, requirement of the pavement above
the subgrade And this thickness requirement of the pavement above the
subgrade.
• Would remains some in respected of the quality of material
