The soil is classified as using the AASHTO method (Ignore the group index)

How is the plasticity index of a soil determined?

Repeat Problem 2.4 with the following data. 2.4 The following are the results of a sieve analysis. a. Determine the percent finer than each sieve and plot a grain-size distribution curve. b. Determine D10, D30, and D60 for each soil. c. Calculate the uniformity coefficient Cu. d. Calculate the coefficient of gradation Cc.

Repeat Problem 2.8 using the following data. 2.8 The following are the results of a sieve and hydrometer analysis. a. Draw the grain-size distribution curve. b. Determine the percentages of gravel, sand, silt and clay according to the MIT system. c. Repeat Part b according to the USDA system. d. Repeat Part b according to the AASHTO system.

State whether the following are true or false. a. In the AASHTO classification Table 4.1, the soils that are more suitable for roadwork are located on the left than right. b. In AASHTO classification system, the better performing fine grained soils are the ones with lower group indices. c. In AASHTO classification system, sands are classified as grains with 0.075-4.75 mm diameter. d. The USCS symbol for clayey gravel is CG. e. A soil with USCS symbol SM is sandy silt.

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 2.35). (a) (b) Figure 2.35 (a) Soil-aggregate stockpile; (b) sieve analysis (Courtesy of Khaled Sobhan, Florida Atlantic University, Boca Raton, Florida) 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. c. Although the soils are obtained from the same stockpile, why are the curves so different? (Hint: Comment on particle segregation and representative field sampling.) d. Determine the percentages of gravel, sand and fines according to Unified Soil Classification System.

In AASHTO, which group are the following soils likely to fall into? a. A well graded gravel with approximately 10% fines. b. A well graded sand with approximately 10% fines. c. A uniform fine sand. d. A high plastic clay.

A hydrometer test has the following result: Gs = 2.65, temperature of water = 26 C, and L = 10.4 cm at 45 minutes after the start of sedimentation (see Figure 2.25). What is the diameter D of the smallest-size particles that have settled beyond the zone of measurement at that time (that is, t = 45 min)? Figure 2.25 ASTM 152H type of hydrometer placed inside the sedimentation cylinder (Courtesy of Khaled Sobhan, Florida Atlantic University, Boca Raton, Florida)

For a soil, given: D10 = 0.08 mm D30 = 0.22 mm D60 = 0.41 mm Calculate the uniformity coefficient and the coefficient of gradation of the soil. 2.4 Repeat Problem 2.3 for the following: D10 = 0.24 mm D30 = 0.82 mm D60 = 1.81 mm

The properties of seven different clayey soils are shown below (Skempton and Northey, 1952). Investigate the relationship between the strength and plasticity characteristics by performing the following tasks: a. Estimate the plasticity index for each soil using Skemptons definition of activity [Eq. (4.28)]. b. Estimate the probable mineral composition of the clay soils based on PI and A (use Table 4.3) c. Sensitivity (St) refers to the loss of strength when the soil is remolded or disturbed. It is defined as the ratio of the undisturbed strength (f-undisturbed) to the remolded strength (f-remolded)) at the same moisture content [Eq. (12.49)]. From the given data, estimate f-remolded for the clay soils. d. Plot the variations of undisturbed and remolded shear strengths with the activity, A, and explain the observed behavior.