Three groups of students from the Geotechnical Engineering class collected soil-aggregate samples for laboratory testing from a recycled aggregate processing plant in Palm Beach County, Florida. Three samples, denoted by Soil A, Soil B, and Soil C, were collected from three locations of the aggregate stockpile, and sieve analyses were conducted (see Figure 2.37 on the next page).
a. Determine the coefficient of uniformity and the coefficient of gradation for Soils A, B, and C.
b. Which one is coarser: Soil A or Soil C? Justify your answer.
Figure 2.37

c. Although the soils are obtained from the same stockpile, why are the curves so different?
d. Determine the percentages of gravel, sand, and fines according to Unified Soil Classification System.

100 -Soil --+-Soil B -+-Soil C 80 60- 40 20 0 100 10 0.1 0.01 Particle size (mm)