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46. For laying bituminous carpet over water bound macadam road surface, one has to apply a ____. |
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A. bitumen grout |
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B. slurry coat |
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C. seal coat |
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D. tack coat |
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Answer: D tack coat |
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Explanation: Bituminous tack coat is the application of bituminous material over an existing pavement surface which is relatively impervious like an existing bituminous surface or a cement concrete pavement or a pervious surface like the WBM which has already been treated by a prime coat. |
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47. In a cement concrete pavement dowel bars are used in ____. |
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A. dummy joints |
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B. expansion joints |
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C. construction joints |
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D. longitudinal joints |
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Answer: B expansion joints |
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Explanation: Longitudinal joints in cement concrete pavements are constructed with suitable tie bars. Dowel bars are provided at expansion joints and sometimes at contraction joints. |
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48. The total thickness of pavement by CBR method depends on the CBR value of ____. |
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A. subgrade |
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B. base course |
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C. surface course |
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D. All layers |
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Answer: A subgrade |
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49. The modulus of subgrade reaction is obtained from the plate bearing test in the form of load deformation curve. The pressure corresponding to the following settlement value should be used for computing modulus of subgrade reaction ___. |
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A. 0.250 cm |
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B. 0.150 cm |
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C. 0.175 cm |
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D. 0.125 cm |
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Answer: D 0.125 cm |
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The modulus of subgrade reaction ‘k’ is given by, k = P/Δ = P/0.125 kg/cm³ |
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50. In the plate bearing test, if the load applied is in the form of an inflated type of wheel, then this mechanism corresponds to ____. |
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A. semi-rigid plate |
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B. rigid plate |
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C. semi-elastic plate |
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D. flexible plate |
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Answer: D flexible plate |
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Plate bearing test conducted with a mild steel plate is considered relevant to the condition of rigid plate as in equation Δ = 1.18 pa/Es The wheel loads through inflated rubber tyres may be considered as flexible plate loading or loading with uniformly distributed pressure as in equation Δ = 1.5 pa/Es where, p = uniform pressure of loaded plate, a = radius of plate and Es modulus of elasticity of the soil |