Highway Engineering (101-120)

101. The group index for a soil, whose liquid limit is 40 percent, plasticity index is 10

percent and percentage passing 75 micron IS sieve is 35, is 0

---

102. Bottom most layer of pavement is known as subgrade

---

103. Flexible pavement distribute the wheel load through a set of layers to the subgrade

---

104. The number of repetitions, which the pavement thickness designed for a given wheel load should be able to support during the life of pavement is

1000000

---

105. Group index method of design of flexible pavement is an empirical method based on physical properties of subgrade soil

---

106 Minimum and maximum values of group index can be 0 and 20 respectively

---

107. If the group index value of subgrade is between 5 and 9, then the subgrade is

treated as poor

---

108. Tyre pressure influences the quality of surface course

---

109. Rigidity factor for a tyre pressure greater than 7 kg/cm² is less than 1

---

110. In a dual wheel assembly if P is equal to each wheel load, S is centre to centre

distance of dual wheels and d is the distance between walls of wheels, then

total stress due to the dual wheels at any depth greater than 2 S is equiva

lent to a single wheel load of magnitude 2 P

---

111.Main drawback of CBR method is that it gives the total thickness which

remains the same irrespective of the quality of materials used in the' component layers

---

112.Radius of relative stiffness in cm is given by

where.E = modulus of elasticity of cement

concrete, kg/cm²

μ = Poisson's ratio for concrete

h = slab thickness, cm

k = subgrade modulus, kg/cm³

---

113.Critical load position in a rigid pavement design is taken as

interior, edge and corner loading

---

114. If the radius of wheel load distribution is 30 cm and slab thickness is 15 cm, then the equivalent radius of resisting section is 30 cm

---

115. The critical combination of stresses for corner region in cement concrete roads is load stress + warping stress

---

116. Tie bars in cement concrete pavements are at longitudinal joints

---

117. The maximum spacing of contraction joints in rigid pavements is 4.5 m

---

118. The maximum thickness of expansion joint in rigid pavements is 25 mm

---

119. The function of an expansion joint in rigid pavements is to allow free expansion

---

120. A traffic survey revealed the present average daily traffic of commercial vehicles as 1000. The annual rate of growth of traffic is found to be 8 percent. The

pavement construction is to be completed in three years after the last traffic count.Then the number of vehicles for design of rigid pavements will be taken as

1000 (1.08)²³