305In-Grade Modification

305.01 Description. This work consists of modifying in place materials by

incorporating other materials and constructing one or more courses in accordance with these specifications and in reasonably close conformity with the lines, grades, and typical cross sections shown on the plans or established by the Engineer.

305.02 Materials.

305.02.1 Materials to be Modified . The materials to be modified shall consist of

material in place on the roadbed or material placed under this contract or a combination thereof. General conditions governing the use of materials shall be as set out in Section 106.

305.02.2 Stabilizer Aggregates . Stabilizer aggregates of the kind and size specified

shall meet the requirements of Subsection 703.20.

305.03 Construction Requirements.

305.03.1 Equipment. The methods and equipment used in performing the work shall

meet the requirements of Subsection l08.05. Equipment necessary for proper prosecution of the work shall be on the project and approved by the Engineer prior to commencing work. Watering equipment shall have pressurized spray bars with suitable nozzle openings. Mixing and scarifying equipment shall have positive depth controls. Rollers shall be of sufficient number, type , size, and weight to accomplish the required compaction. When measurement for payment for stabilizer ag gregate is to be made by the ton, the Contractor shall furnish approved platform s cales capable of weighing the entire loaded vehicle. Scales and their use shall be in accordance with the requirements set out in Subsection 40l.03.2.1.11, except they shall be installed at an approved location on or near the project.

305.03.2 Processing.

305.03.2 1--Before Addition of Stabilizer Aggregate. The material to be modified shall

be prepared in accordance with the requirements of Section 321. In addition, if the existing surface consists of bituminous surfacing, the surfacing shall be scarified, pulverized, and thoroughly mixed until all the ma terial will pass a three-inch sieve. The material shall then be brought to the designated lines, grades, and cross sections and to the required density. To ensure proper prosecution of the work, sufficient roadbed shall be prepared in advance of spreading stabilizer aggregate.

305.03.2 2--After Addition of Stabilizer Aggregate . After the roadbed and in-place

material have been prepared as specified and approved, the designated quantity of aggregate to be added shall be uniformly spread. The Contractor shall organize the work so that delay in spreading and incorporation of aggregate will be only for the time necessary to haul the re quired quantity of stabilizer materials on a section of sufficient length to permit a single effective spreading, mixing, shaping, and compacting operation. Dumping of long lines of stab ilizer aggregates on the roadbed and prolonged periods of hauling adjacent thereto will not be permitted. Unless wet soil conditions prevent satisfact ory manipulation, aggregates shall be incorporated not later than the following day. Preliminary scarifying shall be carefully controlled, and the undisturbed foundation beneath the loose material shall have a crown conforming as nearly as practicable to that of the finished course. Mixing shall immediately follow the proper distribution of the aggregate and shall be performed with rotary or other agitating type mixers, supplemented by other equipment as necessary to pulverize the materials and th oroughly incorporate each into the other so that the resulting course will be uniform throughout. During mixing, sufficient water shall be added to bring the material to the proper moisture content. Mixing shall be carefully controlled to provide an undisturbed underlying foundation at the designed grade and cross section, and shall be continued until a minimum of 95.0 percent of all materials, exclusive of individual rocks or stone, will pass a two-inch sieve. The first section of each modified course constructed will serve as a test section. The length of the test section shall be determined by the capabilities of the equipment selected to perform the work but will be at least 1000 feet and not more than 1500 feet for the designated width. The Contractor and Engineer will evaluate the results of the test section in relation to contract requirements. In case the Engineer determines the work does not comply with contract requirements, the Contractor’s procedure and augment or equipment shall be revise as necessary to provide work completed in accordance with the contract and shall correct all deficient work at no additional cost to the State. The Contractor shall be fully responsible for damage to or contamination of the underlying material or shoulder material a nd shall make corrections as necessary at no additional cost to the State. For the purpose of determining reasonable co nformity with the designated width of a course, the width of a course shall not vary from the designated edge lines by more than plus or minus three inches. A course whose compacted thickness is designate d to be more than eight inches shall be constructed in two or more layers of ap proximately equal thickness. The maximum compacted thickness of any one layer shall not exceed eight inches. No material shall be placed on or mixed with frozen material.

305.03.3 Shaping, Compacting and Finishing . Compaction shall start longitudinally

at the outer edges of the course and proceed toward the center. The material shall be sprinkled or aerated as necessary during compaction to maintain the needed moisture content for compaction. Shaping and compacting shall be carried out in a manner that will prevent lamination and shall continue until the entire depth and widt h of the course has reached the required density. Throughout the entire compaction op eration, the shape of the course shall be maintained by blading and rolling. Surface compaction and finishing shall be performed so as to produce a smooth, closely knit surface, free from lamination, cracks, ridges, or loose material, and conforming to the required section and established lines and grades. Prior to subsequent construction or release of maintenance, all irregularities, depressions, soft spots, and other deficiencies shall be corrected to meet the requirements of these specifications without additional compensation. Density tests will be performed in accordance with the methods as provided in Subsection 700.03 and 700.04. Determination of acceptance of compaction of in-grade modification for required density will be performed on a lot to lot basis. Each lot will be 2,500 linear feet per layer placed. At the discretion of the Engineer, a residual portion of a lot completed during a day's operation may be considered as a separate lot or may be included in the previous or the subsequent lot, except that any day's operation of less than one full lot will be considered a lot. The lot will be divided into five approximately equal sublots with one density test taken at random in each sublot. The average of th e five density tests shall equal or exceed 93.0 percent with no single density test below 89.0 percent. In addition to the requirements for density a nd correction of deficiencies, the Contractor shall be fully responsible for constructing and maintaining a course which will remain firm and stable under constr uction equipment and other traffic the course will be subjected to prior to release of maintenance.