Answer Happy

Grain size distributions curves are given for 9 soils in Figures 1, 2 and 3. The Liquid Limit and Plastic Limit for the fine-grained portion of these soils are given in Table 1. a) Classify the soils according to ASTM/USCS (i.e., give both the Group Symbol and Group Name). b) It is proposed that Soil 3 (Figure 2) be used for a highway subgrade. What is the AASHTO soil classification for this soil (see classification table on the last page of this assignment)? What is this soil's general rating as a subgrade?

3 in. in. U.S. Standard sieve size No.4 No.10 No. 40 No. 200 TTTT 100 90 80 70 60 3 2. +2 Percent finer by weight (or mass) 50 40 30 20 10 o L 100 ابيا 10 0.01 0.001 1.0 0.1 Grain size (mm) SAND Medium Fine GRAVEL COBBLES SILT OR CLAY Coarse Fine Coarse Figure 1

in. 3 in. 100 U.S. Standard sieve size No.4 No. 10 No. 40 No. 200 TT דיויד 90 3 80 | 70 60 Percent finer by weight (or mass) 50 40 30 20 10 البيبليبيا 0 100 10 0.01 0.001 1.0 0.1 Grain size (mm) SAND Medium Fine COBBLES GRAVEL Coarse Fine SILT OR CLAY Coarse Figure 2

نما | م in. 3 in. 100 U.S. Standard sieve size No.4 No.10 No. 40 No. 200 . 90 1 1 1 1 80 70 60 Percent finer by weight (or mass) 50 40 30 20 2. 10 بيليا 0 100 10 0.01 0.001 1.0 0.1 Grain size (mm) SAND Coarse Medium Fine COBBLES GRAVEL Coarse Fine SILT OR CLAY Figure 3

Table 1: Atterberg Limits for Soil Materials Soil # LL PL Figure # 1 1 1 N/A N/A N/A 2 N/A 1 3 1 2 2 ס|ס|ס| ק 2 2 2 N/A 34 40 64 46 30 75 N/A 32 28 35 30 3 1 3 2 27 32 3 3