Utilization of Waste Incineration Bottom Ash to Enhance Engineering Properties of Expansive Subgrade Soils

Table 1

ERA manual-2002 rating of subgrade, subbase, and base-course materials based on the CBR value.

CBR (%)	General rating	Uses
0–3	Very poor	Subgrade
3–7	Poor to fair	Subgrade
7–20	Fair	Subbase
20–50	Good	Base coarse/base
>50	Excellent	Base coarse