University of South Alabama Department of Civil, Coastal, and Environmental Engineering CE490/590 Pavement Design Homework #6 (100 points) Due: 5:00 pm Wed Feb 20 1. A fine-grained soil has an unconfined compressive strength of 2.3 tsf. The results of repeated load testes are shown below. (1) Develop equations relating the resilient modulus to the deviator stress. (2) What should be the minimum and maximum resilient modulus for this soil? Deviater stress, psi Recoverable strain, 10-4 2 1.41 4 3.2 7 7.61 14 18.9 20 30.32 28 51.81 2. Recycled materials such as reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) have been used in asphalt mixtures. A contractor has designed a JMF using RAP and RAS, as attached. Please answer the following questions: (1) What are advantages and disadvantages use RAP and RAS in HMA? (2) How many stockpiles does this mix have? (3) Relying on the data in the JMF, show all the equations how to calculate air void = 4.0%, VMA = 14.9%, VFA = 73.1%, and the blended aggregate specific gravity Gsb = 2.648. (4) Show how to determine Asphalt Binder Replacement (ABR) ratio. (5) For MEPDG Level II design, we need E* input with appropriate estimation using Witczak equation. Estimate E* at each conditions below for the air void = 4%. Plot the figure with a-axis as frequency and y-axis, including temperatures, and comment on how temperature and frequency affect E*? Note: use A and VTS to calculate viscosity of asphalt at each temperature. For this binder, A = 10.3120, VTS = −3.4400. (1 Poise = 100 cP) Frequency, Temperature, Viscosity of asphalt E* (psi) Hz °F (106, Poise) 20 14 20 32 20 86 20 122 5 14 5 32 5 86 5 122 1 14 1 32 1 86 1 122 0.01 14 0.01 32 0.01 86 0.01 122
Purchase answer to see full attachment