30 Questions
What does the reliability factor R% in pavement design represent?
The probability that the pavement designed will not reach the terminal serviceability level before the end of the design period
What is the purpose of incorporating a reliability factor R% in pavement design?
To account for uncertainties in traffic prediction and pavement performance
What does So represent in the context of flexible and rigid pavements?
Standard deviation for flexible and rigid pavements
Which functional classification requires the highest level of reliability according to AASHTO guidelines?
Interstates and other Freeways in urban areas
Which parameter is used to determine the resilience of the subgrade in pavement design?
Resilient modulus of the subgrade
What is recommended as the level of reliability for local roads in both urban and rural areas?
50 - 80%
What is the initial serviceability index of the highway?
4.2
What is the Marshall stability of the asphalt concrete surface layer?
1600 Ib
What is the resilient modulus of the subgrade?
5 ksi
What is the required subbase thickness if the thicknesses are not satisfactory?
7 in.
What is the percentage that the pavement is exposed to saturation?
25%
What is the reliability of the highway?
95%
What is the elastic modulus of the surface course?
360,000 psi
What is the terminal serviceability level of the pavement?
2.5
What is the drainage coefficient of the base course?
1.20
What is the value of a1 obtained from Fig. 5?
0.40
What is the thickness of the subbase course (D3) rounded to the nearest whole number?
13.5 in.
What is the total estimated traffic that the flexible pavement is designed to carry over the design period?
2.5 million ESAL
What is the function of the total pavement thickness requirement?
Dependent on the resilient modulus of subgrade soil
What is a common practice when laboratories are not equipped to perform the resilient modulus test for soils?
Estimate Mr through empirical correlation with other soil properties
Which equation provides a correlation suggested by AASHTO for fine-grained soils with soaked CBR of 10 or less?
Equation (62.11)
In computing the effective Mr, how does AASHTO suggest estimating relative damage corresponding to each seasonal modulus?
$\text{Relative damage} = \frac{Mr}{1000}$
According to AASHTO, what is the purpose of an effective roadbed soil Mr?
To represent the combined effect of all seasonal modulus values
What is the typical range of values for the regression constant K1?
1500-6000
What is the first step suggested by AASHTO in computing the effective Mr?
Divide the year into equal-length time intervals
How is the total structural number required above the subgrade soil, denoted SN3, determined?
Using the nomograph in Fig. 3 with Mr as input
What is used to replace Mr to determine SN2?
E2 (stiffness modulus of base course material)
What is used to replace Mr to determine SN1?
E3 (stiffness modulus of subbase material)
What is the typical range of values for the regression constant K2?
0.4-0.6
In Example 62.9, what is the design lane ESAL to be carried by the constructed pavement on the subgrade with Mr 5655psi?
5 x 10^6
Learn about how the design traffic loading in Equivalent Single Axle Load (ESAL) is computed using the provided equation, along with a discussion on other input parameters involved. This quiz covers topics related to highway engineering and design standards.
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