210Subgrade Compaction

210.1 Description. This work shall consist of compacting the earth subgrade on the roadbed of a previously

graded roadway. This work shall be performed prior to any work under Sec 209. The contractor shall perform this work on the subgrade at all locations specified by the engineer. Tentative locations of subgrade compaction will be shown in the plans, but the engineer will specify all locations and depths of this work by written order. No contract adjustment will be made for the direct or indirect costs, incidental or consequential costs, or effects of any overrun, or partial or complete underrun.

210.2 Construction Requirements.

210.2.1 The subgrade for the full width of the roadbed shall be scarified to a depth of at least 6 inches, and the

scarified material shall be brought to a uniform moisture content either by drying or by adding water and manipulating. At the contractor's option, the upper 6 inches of soil may be removed and replaced with satisfactory material, or removed and manipulated before replacing. The material shall be compacted to the required density and within the moisture contents specified under Sec 203.5.

210.2.2 If it is determined that the required subgrade density cannot be obtained by moisture control and

compaction of the upper 6 inches, the unsuitable material shall be excavated to a maximum depth of 18 inches, and replaced with satisfactory material compacted in layers not to exceed 6 inches, except as otherwise permitted by the engineer. Each 6-inch layer shall be processed, wetted or dried as necessary, and compacted to the required density.

210.2.3 If the contractor’s operations cause an unsatisfactory subgrade, the contractor shall restore the subgrade

to a satisfactory condition at the contractor's expense.

210.3 Method of Measurement. Measurement will be made to the nearest 1/10 station along the centerline of

each roadbed, regardless of width, for each depth of compaction authorized and totaled to the nearest 100 feet for the sum of all segments. For the purpose of measurement, a divided highway will be considered as having two roadbeds. Measurement of ramps will be made from the ramp’s gore point.

210.4 Basis of Payment. The accepted quantity of subgrade compaction, 6-inch depth, will be paid for at the

contract unit price. Subgrade compaction to a depth of 12 inches will be paid for at the rate of two times the contract unit price for subgrade compaction, 6-inch depth. Subgrade compaction to a depth of 18 inches will be paid for at the rate of three times the contract unit price for subgrade compaction, 6-inch depth.