This set of Railway Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Blanket and Blanketing Material”.
1. What should be the maximum percentage of plastic fines present in non-cohesive material?
Explanation: Fines are the particles measuring up to 75mm. in sand, gravel, and other non-cohesive materials they should not exceed more than 5% value.
2. What should be the maximum liquid limit value for Macadam type materials?
Explanation: For Macadam type materials liquid limit should not exceed 35 and plasticity limit should be less than 10. The coefficient of uniformity should be above 4.
3. Which of the following is the correct expression for calculation of Coefficient of curvature?
a) D30/D60 × D10
b) D230/D60 × D10
c) D30/D60 × D40
d) D230/D40 × D10
Explanation: Coefficient of curvature can be calculated by the expression D230/D60 × D10. Its value for Macadam materials should be between 1 and 3.
4. Which test is used for determining the dry density of the material?
a) Proctor’s test
b) Blain’s test
c) Vicat’s test
d) Alexander’s test
Explanation: Compaction of Macadam should be done near the optimum moisture content to achieve at least 90% of the maximum dry density which is determined by Proctor’s test.
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