Department of Civil Engineering
SUB-Highway Engg.
TOPIC NAME-Road Materials(Part-1)
BY
ER. Ankit Joshi
(Asst Hod. CIVIL Engineering Department)
AY:2021-2022
Road materials are divided into
3 major categories
Soil
Aggregates
Binders
SOIL
Origin of Soil
Grains are divided into 4 major categories
Gravel
Sand
Silt
Clay
Classification of soil according to grain size
Types of Soil :-
According to texture and grain size it is divided into the following categories
Sand
Silt
Clay
Loam
S.L
Sandy Loam
C.L.
Silty Sand
Clayey Sand
Silty Clay
Phase system of Soil
It is of two types :-
Atterberg limits
Unified Classification System
Group Index = 0.2a + 0.005a.c + 0.01b.d
Where,
a = portion of material passing 0.074mm sieve, greater than 35% and not exceeding 75 % .
b = portion of material passing 0.074 m sieve And greater than 15% & not exceeding 35%
c = Value of liquid limit in excess of 40% and less that 60%
d = value of plasticity index exceeding 10% and not more than 30%
Q-1 ) Find out the Uniformity Co-efficient & Co-efficient of gradation by using the
following table
Sieve Size ( mm) | % Passing |
4.75 | 60 |
2.00 | 30 |
0.60 | 10 |
0.40 | 5 |
0.20 | 0 |
Q-2 ) The index properties of soil are given below :-
Passing 0.074mm sieve = 55%
Liquid Limit = 50%
Plastic Limit = 41%
Find out Plasticity index & Group Index of the above.
Solution :-
Given Data,
Passing 0.074mm sieve = 55%
Liquid Limit = 50%
Plastic Limit = 41%
Plasticity Index = L.L. – P.L.
Group Index = 0.2a + 0.005a.c + 0.01b.d
a = 55 – 35 = 20
b = 55 – 15 = 40
c = 50 – 40 = 10
d = 9 – 10 = 0 ( min )
Group Index = 5.0
Active & Passive Earth Pressure