134. For maximum strength and durability minimum percentage of cement, by weight is

A.15%

B.20%

C.25%

D.30%

135. Pick up the incorrect statement from the following. If water cement ratio is

A. increased, strength of concrete increases

B. decreased, strength of concrete increases

C. increased, strength of concrete is not affected

D. none of these.

136. To indicate proper control of consistency of a freshly mixed concrete for pavement construction, the slump should be between

A. 3 to 5 cm

B. 4 to 6 cm

C. 5 to 7 cm

D. 7 to 10 cm

137. Minimum number of 50 kg cement bags per cubic metre of concrete for a mix corre-sponding to crushing strength 280 kg/cm2 at 28 days, are

A.5

B.6.5

C.7

D.7.5

138. If E is the modulus of elasticity of the concrete in kgkm2, d is the slab thickness in cm, 1.t is the Poisson's ratio for the concrete, k is the sub-grade modulus kg/cm3, the radius r of relative stiffness in cm,

A. 50 cm

B. 60 cm

C. 70 cm

D. 80 cm

139. When load is applied on concrete pavement

A. away from edges, the maximum bending moment is negative

B. away from edges, the maximum bending moment cause compression

C. on the edges, the maximum stress is parallel to the edge of the slab

D. none of these.

140. If d is the thickness of a concrete pavement, the equivalent radius b of resisting section for an interior loading, is

A. b = 10.6 + d2 - 0.675 d

B. b = 1.6 + d2 + 0.675 d

C. b =-111.6 + d2 - 3.675 d

D. b = /1.6 + d2 - 0.675 d.

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