Questiоn 2. Circle the cоrrect chоice for the following sentences, fill in the blаnks, or show detаiled cаlculations (2 points each unless otherwise mentioned): In the AASHO Road Test, which base type for flexible pavement test sections performed best? a. ATB b. CTB c. River gravel d. Crushed stone 2. Where did the most rutting happen in the layers of the flexible test sections of the AASHTO Road Test? a. AC Layer b. Base Layer c. Subbase Layer d. Embankment 3. Which of the following pavement types has higher stress transmitted to the subgrade layer? a. Rigid b. Flexible 4. Why is there higher stress in (3)? 5. Which axle configuration results in the least damage in asphalt pavements for the same load? a. Single b. Tandem c. Tridem d. Quad 6. What is the actual contact area shape between the tire and the pavement? a. One middle rectangular portion surrounded by two semi-circles b. Rectangular c. Circular d. Trapezoidal 7. What is the standard load on a single axle as defined by AASHTO? a. 18 kips b. 20 kips c. 22 kips d. 24 kips 8. If the load on a tandem axle with four tires on each side is 40,000 lb and the tire pressure is 100 psi, then the imprint area for each tire is most nearly a. 400 sq. in b. 42.5 sq. in. c. 50 sq. in. d. 55 sq. in. 10. The terminal serviceability of asphalt pavements on a primary route like a rural Interstate, according to the 1993 AASHTO Pavement Guide, is usually taken as ___________________ 11. According to the Corps of Engineers, soils with more than the following percentage of materials finer than 0.02 mm in size are usually considered frost-susceptible: a. 1% b. 2% c. 3% d. 4% 12. Which parameter (s) is/are commonly used for quality control of subgrade soil compaction? a. Optimum moisture content b. Maximum dry density c. Both (i) & (ii) d. Neither (i) or (ii) 13. If the deviatoric stress increases in a triaxial test, the resilient modulus of fine-grained soil will a. Decrease b. Increase c. Remains unaffected d. Was not discussed in the class 14. If the deviatoric stress increases in a triaxial test, the resilient modulus of coarse-grained soil will a. Decrease b. Increase c. Remains unaffected d. Was not discussed in the class 15. (5) An LFWD test (150-mm diameter plate) was performed on a soft subgrade. A total load of 11 KN was applied to the plate, and the measured deflection at the center of the plate was 550 microns. Assuming Poisson’s ratio of 0.4, compute the elastic modulus of the subgrade layer. [E = {Π(1-γ2) σo.a}/(2do)] ______________________________ 16. (5) A 2-lane, 2-way major rural arterial highway under reconstruction has an AADT of 10,000 during the design year. The annual growth rate is expected to be 2%. The percentage of trucks is 10%. The truck factor has been estimated to be 0.40 for all trucks. Estimate the cumulative ESALs for this highway on the design lane for a 20-year design period. [Cum. ESAL = AADT*T* D*Tf * G * Y * 365 where G * Y = {1 + r) Y - 1}/(r)] ____________________________________________ 17. In the current accelerated pavement testing at KSU, 500,000 repetitions of an 18-kip load on a single axle have been applied. What would be the equivalent number of 18-kip ESALs used assuming the fourth power relationship? _________________________ 18. Which of the following sources is responsible for the most moisture in the pavement system? a. Surface infiltration b. Groundwater c. Capillary action d. Seepage 19) The minimum coefficient of permeability of a drainable base, as recommended by FHWA, is a. 300 ft/day b. 500 ft/day c. 1000 ft/day d. 3000 ft/day 20)The drainable base's thickness, as FHWA recommends, is a. 250 mm b. 200 mm c. 150 mm d. 100 mm