Technical information

2-5
moisture contents for sections N1 and N2 were 10% and 11% respectively. The average
in-place wet unit weight was 132.0 pcf (2116 kg/m³) for both sections, and the
corresponding dry unit weights were 120.0 and 118.9 pcf (1924 and 1906 kg/m³). From
this information it may be concluded that the relative in-place degree of compaction,
based on dry densities, was 100.3% and 99.4% for sections N1 and N2 respectively.
Figure 2.2.2: Final gradation of upper subgrade soil at N1 and N2 sections (Timm and
Priest, 2006).
2.2.3 Granular Base
The granular base consisted of a well graded crushed granite material, compacted in a
single 6 in. (152 mm) layer. The gradation of this material is shown in Figure 2.2.3. As
can be seen, 100 percent of the material is smaller than the 1.5 in. sieve (38.1 mm
opening). Also note that less than 10% of the material is passes the #200 sieve (0.075
mm opening). Loose base samples were recompacted in the lab using modified Proctor
effort, resulting in a maximum dry unit weight of 137.9 pcf (2211 kg/m³) and a
corresponding moisture content of 9.2% (i.e., laboratory optimum). The average field