CDD buoi 12

Multiple Choice

What is the significance of strengthening old pavement structures in road design?

• It increases the lifespan and durability of roads.

• It reduces the need for regular maintenance.

• It helps in accommodating higher traffic loads.

• It improves the aesthetic appearance of roads.

Open Ended

Based on the table, how does the condition of the surface layer affect the selection of the layer coefficient (hệ số lớp a) for pavement strengthening?

Multiple Choice

What is the typical range for the loss of PSI (ΔPSI) used in the design of strengthening old flexible pavements?

• 1.7 to 2.5

• 0.5 to 1.0

• 2.5 to 3.5

• 3.0 to 4.0

Multiple Select

Which of the following statements about classifying subgrade soil quality for low-traffic flexible pavement design are correct?

• 'Rất xấu' corresponds to MR < 20 MPa and CBR < 2%

• 'Tốt' corresponds to MR > 42 MPa and CBR = 7%

• 'Trung bình' corresponds to MR > 30 MPa and CBR = 5% to 6%

• 'Xấu' corresponds to MR > 60 MPa and CBR > 8%

Fill in the Blanks

The structural number (SN) for flexible pavement design can be calculated using the formula: 2.54.SN = a1.D1 + a2.D2 + a3.

Multiple Choice

For a flexible pavement with a crushed stone base and a total equivalent single axle load (ESAL) between 10,000 and 30,000, what is the required thickness of the base layer if the subgrade is classified as 'Tốt' and the traffic level is 'Thấp'?

• 10 cm

• 15 cm

• 20 cm

• 28 cm

Open Ended

Explain how the use of local materials (SB) as a subbase can reduce the required thickness of the crushed stone base (BS) in flexible pavement design for low-traffic roads. Use the example provided to illustrate your answer.

Open Ended

Based on the table, how does the condition of the surface layer affect the selection of the layer coefficient (a) for reinforced base layers in pavement design?

Multiple Select

What are the three methods to determine the effective structural number (SNeff) of an existing pavement structure?

• Laboratory testing of pavement materials

• Non-destructive testing using FWD equipment

• Investigation and survey of pavement condition

• Measuring pavement deflection using Benkelman beam