Subgrade
Defined in the standard specifications of 8 state transportation agencies. Each definition below is the agency’s own text, with the section it comes from — they do not all say the same thing, and on a contract the difference is the point.
Definitions are quoted from state-authored public specification books. This page carries no I-Code-derived terms.
The top surface of a roadbed upon which the pavement structure, shoulders, and curbs are constructed. Subgrade that has been treated with lime, fly ash, cement kiln dust, or combinations thereof for stabilization will be considered subbase.
Section 101 — DEFINITIONS AND TERMS →The portion of the roadbed immediately below the base course or pavement, including below the curb and gutter, valley gutter, shoulder and driveway pavement. The subgrade limits ordinarily include those portions of the roadbed shown in the Plans to be constructed to a design bearing value or to be otherwise specially treated. Where no limits are shown in the Plans, the subgrade section extends to a depth of 12 inches below the bottom of the base or pavement and outward to 6 inches beyond the base, pavement, or curb and gutter.
Section 1 — DEFINITIONS AND TERMS →Materials directly below the pavement structure. The subgrade is natural in- place material (e.g., excavated areas) or compacted fill material (e.g., embankments).
Section 101 — GENERAL, ABBREVIATIONS, AND DEFINITIONS →The top surface of a roadbed upon which the pavement structure and shoulders includin g curbs are constructed.
Section 101 — DEFINITIONS AND TERMS →The surface upon which the pavement structure, including shoulders, are constructed.
Section 101 — General Information, Definitions, and Terms →Portion of the earth grade upon which the pavement structure is placed.
Section 101 — Terms, Format, and Definitions →The top surface of a roadbed upon which the pavement structure and shoulders are constructed.
Section 101 — DEFINITIONS AND TERMS →The portion of the Roadbed prepared as a foundation for the Pavement
Section 101 — Abbreviations, Symbols, T erms, and Definitions →