Category:302 Stabilized Permeable Base

302.1 Construction Inspection for Sec 302

302.1.1 Description (Sec 302.1)

Treated permeable base provides a structural, highly permeable drainage layer. This work consist of furnishing and placing a stabilized permeable base material.

302.1.2 Material (Sec 302.2)

302.1.2.1 General (Sec 302.2.1)

Stabilized permeable base shall be either asphalt binder stabilized or Portland cement stabilized at the option of the contractor.

302.1.2.2 Asphalt Stabilized Permeable Base (Sec 302.2.2)

All proportioning, mixing, and transporting shall be in accordance with Sec 401.

302.1.2.3 Cement Stabilized Permeable Base (Sec 302.2.3)

All proportioning, mixing, and transporting shall be in accordance with Sec 401. Fly ash and ground granulated blast furnace slag shall not be used. Cement and water must conform to specific material requirements of Sec 1019 and Sec 1070. Water must be free from substances deleterious to hardening of cement. Water from sources approved for drinking purposes is normally satisfactory.

302.1.3 Construction Requirements (Sec 302.3)

Review the general construction requirements listed in Construction Inspection for Bases and Aggregate Surfaces. Many of the requirements for producing and placing treated permeable bases are also those specified for asphalt concrete, portland cement concrete, and portland cement concrete pavement. Check the appropriate specifications for applicable provision.

302.1.3.1 Contamination (Sec 302.3.1)

Contamination, filling voids with foreign material, will destroy the bases’ function. The engineer should be alert to this problem and require the contractor to take steps to ensure the base remains free of any foreign material.

302.1.3.2 Displacement (Sec 302.3.2)

Rutting effects the ability of the base to drain and results in areas of deficient thickness. Rutting or other displacement of the permeable base or the underlying base is not permitted. If displacement occurs, which could result in ponding or a non-uniform, non-draining thickness of permeable base, the material must be completely removed without disturbing the adjacent or underlying material and shall be replaced at the contractor’s expense.

302.1.3.3 Asphalt Stabilized Permeable Base (Sec 302.3.3)

Applicable sections of Sec 401 apply, except as noted herein. Observe temperature requirements and the rolling of asphalt treated bases to ensure compaction meets specifications. Ensure minimum lift thicknesses are maintained and document.

302.1.3.4 Cement Stabilized Permeable Base (Sec 302.3.4)

Cement Stabilized Permeable Base consists of base aggregate, cement, and water uniformly mixed, hauled and spread in one layer, compacted, finished, and cured in accordance with Sec 501 of Standard Specifications, and in reasonably close conformity with lines, grades, thickness, and typical cross sections shown on the plans.

Subgrade should be prepared and shaped in accordance with Sec 209 of Standard Specifications. Soft or spongy areas in subgrade should be removed, replaced with satisfactory material, and properly compacted. All drainage conduit, including underdrain if required, should be in place.

Ensure minimum lift thicknesses are maintained and documented.

302.1.4 Method of Measurement (Sec 302.4)

Final measurement of the completed permeable base will not be made except for authorized changes during construction or where appreciable errors are found in the contract quantity.

302.1.5 Basis of Payment (Sec 302.5)

The accepted quantities of permeable base of the thickness specified will be paid for at the contract unit price for each of the pay items included in the contract.

302.2 Material Inspection for Sec 302

This guidance establishes procedures for mix design of stabilized permeable base. Ingredients for use in stabilized permeable base are to be inspected in accordance with the applicable Materials Inspection Guidance.

302.2.1 Procedure

302.2.1.1 Asphalt Stabilized Permeable Base

Mix design procedures are identical to those shown in Materials Inspection for Sec 401. However, trial mix samples shall not be obtained unless requested by the Field Office. Proportioning, mixing, and transporting are to be in accordance with the applicable requirements of Sec 401.

302.2.2.2 Cement Stabilized Permeable Base

Proportioning, mixing, and transporting are to be in accordance with the applicable requirements of Sec 501.