303.01 Description. This item shall consist of a foundation
course for surface course, for other base courses, or for pavements. It shall be constructed on the prepared subgrade, s ubbase, or other completed base course according to these specificat ions and in substantial conformity with the lines, grades, comp acted thickness, and typical cross section shown on the plans.
303.02 Materials. Aggregate Base Course shall be gravel,
crushed stone, and/or steel slag so proportioned as to meet the requirements for a class of aggregate specified in Table 303-1. Steel slag is allowed for Classes 1 and 2 only. Classes 7 and 8 shall be any mechanically crushed natural rock or stone of i gneous, sedimentary, and/or metamorphic origin produced fro m a solid geological formation by quarrying methods. The Contractor shall have the option of using any h igher numbered class Aggregate Base Course than that spec ified, provided that payment will be for the class specified. Material furnished for Aggregate Base Course, Class 3 through Class 8, shall have a percent of wear by the Los An geles Test not greater than 45 as determined by AASHTO T 96. 195 When it is necessary to blend two or more materials , each material shall be proportioned separately through m echanical feeders to ensure uniform production. Premixing or blending to avoid separate feeding will not be permitted. Prod uction of material by blending materials on the roadway to obtain a mi xture that will comply with the requirements specified herein will not be permitted. For the purpose of this specification, shale and sl ate are not considered to be gravel or stone. The material fur nished shall not contain more than 5% by weight of shale, slate, and other objectionable, deleterious, or injurious matter. For Classes 1 and 8 materials, the fraction passing the #200 (0.075 mm) sieve shall not be greater than three-fo urths of the fraction passing the #40 (0.425 mm) sieve. For Cla sses 3 through 8 the fraction passing the #40 (0.425 mm) sieve shall have a liquid limit not greater than 25. To ensure that gravel is uniformly graded, the diff erence between the percent passing the various sieves shall be as follows for Classes 3, 4, and 5: Sieve Percent 3/4" - 3/8" (19.0 mm - 9.5 mm) 5 min. 3/8" - #4 (9.5 mm - 4.75 mm) 5 min. #4 - #10 (4.75 mm - 2.00 mm) 5 min. #10 - #40 (2.00 mm - 0.425 mm) 4 min. When the material contains aggregate larger than th at specified above for the class called for in the Contract, the oversize aggregate shall be removed by screening or by screening and c rushing. The removal of large size aggregate by hand methods wil l not be permitted.
303.03 Construction Requirements. The base course material
shall be placed on a completed and approved subgrad e or existing base that has been bladed to substantially conform to the grade and cross section shown on the plans. The subgrade shall be prepared as specified in Sect ion 212 and shall be free from an excess or deficiency of moist ure at the time of placing base course material. The subgrade shall a lso comply, where applicable, with the requirements of other it ems that may be contained in the Contract that provide for the cons truction, 196 reconstruction, or shaping of the subgrade or the r econstruction of the existing base course. Base course material shall not be placed on a froze n subgrade or subbase. The aggregate shall be placed on the subgrade or ot her base course material and spread uniformly to such depth and lines that when compacted it will have the thickness, width, a nd cross section shown on the plans. If the required compacted depth of the base course exceeds 6" (150 mm), the base shall be constructed in two or m ore layers of approximate equal thickness. The maximum compacted thickness of any one layer shall not exceed 6" (150 mm) excep t when vibrating or other approved types of special compac ting equipment are used, the compacted depth of a single layer of base course may be increased to 8" (200 mm) upon approval of the En gineer. Each layer shall be stable before advancing to the next layer sequence. The material shall be spread the same day that it i s hauled. Spreading shall be performed in such manner that no segregation of coarse and fine particles nor nests or hard areas c aused by dumping the aggregate on the subgrade will exist. Care sha ll be taken to prevent mixing of subgrade or unspecified material with the base course material during the blading and spreading op eration. Aggregate shall not be dumped or mixed on an existi ng or newly constructed ACHM course or PCC Pavement that will n ot be overlaid under the same Contract or on any open gra ded base course. Mechanical spreading equipment shall be us ed, if necessary, to place the base course on the subgrade. If sufficient working space is not available to all ow proper aeration or addition of water to the base, the base material shall be mixed by any satisfactory method before placement. Each course shall be thoroughly mixed for the full depth of the course and shall be compacted by any satisfactory m ethod that will produce the density hereinafter specified. The agg regate shall be maintained substantially at optimum moisture during the mixing, spreading, and compacting operations, water being a dded or the material aerated as may be necessary. The specifie d grade and cross section shall be maintained by blading throughout t he compaction operation. The material in each course shall be co mpacted to a 197 density, as determined by AASHTO T 310, Direct Tran smission, of not less than 98% of the maximum laboratory density determined in the laboratory by AASHTO T 180, Method D. Aggregat e base course placed in areas outside of the normal travel ed way, such as driveways, islands, gore areas, other incidental co nstruction, and restricted width areas outside of the normal travel ed way which cannot accommodate a full width roller shall be com pacted to a density, as determined by AASHTO T 310, Direct Tran smission, of not less than 95% of the maximum laboratory density . Shoulders are considered to be within the normal traveled way . The aggregate shall be compacted across the full width of applica tion. The compacted base course shall be tested for depth and any deficiencies corrected by scarifying, placing addit ional material, mixing, reshaping, and recompacting to the specifie d density, as directed. Where neither prime coat nor surfacing is provided in the same Contract with the base course, the material in the base course shall be uniformly compacted, stable, and free of segrega ted areas. The Contractor shall maintain the base course in a satisfactory condition until accepted.
303.04 Quality Control and Acceptance. Quality control and
acceptance shall be according to the provisions of Section 306.
303.05 Method of Measurement. Aggregate Base Course will
be measured in vehicles either by the cubic yard (c ubic meter) or by the ton (metric ton).
303.06 Basis of Payment. Work completed and accepted and
measured as provided above will be paid for at the contract unit price bid per cubic yard (cubic meter) or ton (metr ic ton) for Aggregate Base Course of the particular class speci fied, which price shall be full compensation for preparing the subgra de; for furnishing material; for spreading, finishing, watering, manip ulating, and compacting; for performing quality control and acce ptance sampling and testing; and for all labor, equipment, tools, a nd incidentals necessary to complete the work. 198 In cases where the combined specific gravity of the material used for Aggregate Base Course exceeds 2.80 and the meth od of measurement is by the ton (metric ton), the quantit y of material will be adjusted for payment by multiplying the quantity of the material used by a specific gravity of 2.80 and dividing by the higher specific gravity. Payment will be made under: Pay Item Pay Unit Aggregate Base Course (Class__) Cubic Yard (Cubic Meter) or Ton (Metric Ton) SECTION 304 VACANT TABLE 303-1 AGGREGATE BASE COURSE GRADING (AASHTO T 11 AND T 2 7) AND CRUSHING REQUIREMENTS (AHTD TEST METHOD 304) SIEVE (mm) CLASS 1 CLASS 2 CLASS 3 CLASS 4 CLASS 5 CLASS 6 CLASS 7 CLASS 8 PERCENT PASSING 3" (75) 100 100 100 2" (50) 95-100 95-100 95-100 1½" (37.5) 85-100 100 100 100 100 1" (25.0) 60-100 60-100 100 3/4" (19.0 ) 60-100 60-100 60-100 60-100 60-100 50 -90 50-90 65-100 3/8" (9.5) 40-80 40-80 40-80 40-80 40-80 #4 (4.75) 30-60 30-60 30-60 30-60 30-60 25-55 25-5 5 25-55 #10 (2.00) 20-50 20-50 20-45 20-45 20-45 #40 (0.425) 10-35 10-35 10-35 10-35 10-35 10-30 10- 30 10-30 #200 (0.075) 3-15 3-15 3-12 3-12 3-12 3-12 3 -12 3-12 MAX. PLASTICITY INDEX (MINUS #40 MATL.) 13 10 6 6 6 6 6 6 (0.425 mm) MINIMUM PERCENT CRUSHED (RETAINED ON #4 [4.75 mm] SIEVE) 15 MINIMUM PERCENT CRUSHER-RUN MATERIAL 90 90 90 200 SECTION 305 RECONSTRUCTED BASE COURSE
305.01 Description. This item shall consist of reshaping an
existing base course essentially true to grade and typical section, preparatory to the placement of a surface course of pavement and shall be constructed according to these specificati ons and essentially in conformity with the lines, grades, and typical s ections shown on the plans.
305.02 Materials. When required, the Contractor shall furnish
additional aggregate base course of the class speci fied, meeting the requirements of Section 303.
305.03 Construction Methods. The existing base course shall
be scarified for its entire width as shown on the t ypical section to a uniform depth sufficient to eliminate all depressio ns and irregularities. The depth of scarification shall b e carefully controlled to prevent contamination of the base mat erial with subgrade. If the base material becomes contaminate d due to the Contractor's work, the contaminated base shall be r emoved and replaced by the Contractor at no cost to the Depart ment. After the scarifying operation is completed, the ro adbed shall be shaped to the specified grade and cross section and compacted by any satisfactory method that will obtain the densit y herein specified. The base course material shall be maintained at opt imum moisture during the shaping and compacting operations by add ing water or by aerating the material as necessary. The specified grade and section shall be maintained by blading throughout the compa ction operation. The density of the compacted material in the recons tructed base course, as determined by AASHTO T 310, Direct Trans mission, shall be not less than 95% of the maximum laborator y density determined in the laboratory by AASHTO T 180, Metho d D. The reconstructed base course shall be compacted across its full width. The Contractor shall reshape all or any part of the base as many times as may be necessary to secure the desired res ults.
305.04 Quality Control and Acceptance. Quality control and
acceptance shall be according to the provisions of Section 306.
305.05 Method of Measurement. Reconstructed Base Course
will be measured by the station (metric station) me asured along the centerline of the roadway. Roadways in each direct ion of a divided 201 highway will be measured separately, and additional areas outside the normal roadway will be converted to the normal measurement on an equivalent area basis.
305.06 Basis of Payment. Reconstructed Base Course completed
and accepted and measured as provided above will be paid for at the contract unit price bid per station (metric station ) for Reconstructed Base Course, which price shall be full compensation for all scarifying, spreading, and shaping; for all waterin g, manipulating, finishing, and compacting; for performing quality c ontrol and acceptance sampling and testing; and for all labor, equipment, tools, and incidentals necessary to complete the work. Payment will be made under: Pay Item Pay Unit Reconstructed Base Course Station (Metric Station)