*EJM086*

EJM – 086

First Semester M.E. (Civil) Degree Examination, March 2013 (Semester Scheme) HIGHWAY ENGINEERING 2K8HW 101 : Pavement Materials Time : 3 Hours

Max. Marks : 100

Instructions : 1) Answer any five full questions. 2) Missing data may be suitably assumed.

1. a) Mention and explain the desirable properties of road aggregates.

10

b) Explain the mechanism of stripping and adhesion failure. Indicate the various methods to improve adhesion. 10 2. a) Explain bitumen with respect to its origin, preparation and chemical constitution. Mention the properties of bitumen.

10

b) Explain the different types of bituminous emulsion and mechanism of breaking of emulsions. Under what circumstances their use is preferred ? 10 3. a) Mention the advantages of Polymer and Rubber modified bitumen. What are the general requirements of modifiers ? b) Explain the following :

10 10

i) Cutback bitumen ii) Seperation test. 4. a) Briefly explain the various factors which may cause hardening of a binder under service conditions.

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b) What are the fundamental properties of bitumen-stone-water system ? Explain any one theory to evaluate the adhesion property of bitumen on road aggregates. 10 5. a) Differentiate between open graded and dense graded bituminous mixes. Explain the desirable properties of a good bituminous mix.

10 P.T.O.

*EJM086*

EJM – 086

b) A bituminous concrete mix is prepared with aggregates A, B and C mixed in the proportion A : B : C = 55 : 43 : 02. The relative specific gravities of A, B, C and bitumen are 2.80, 2.75, 3.05 and 1.02 respectively. The bitumen content by weight of aggregate is 5.2 % .The prepared specimen weigh 1270 gms. in air and 730 gms. in water. Determine the following : i) Maximum theoretical density ii) Percent air voids in the total mix iii) VMA iv) VFB.

10

6. a) Explain the step-by-step procedure for designing a bituminous mix by Marshall method. 10 b) What is superpave ? Explain the principle and working of a superpave gyratory compactor. 10 7. a) Explain the following : i) Rotational viscometer ii) Bending beam rheometer.

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b) Explain the important properties of concrete and their influence on long term service of a concrete road. 10 8. Write short notes on the following : i) Elastic recovery test ii) Joint filler iii) Static immersion test iv) Selection of superpave binder grades.

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(4×5= 20)