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1012-1 AGGREGATES FOR ASPHALT PLANT MIXES.
(A) Composition of Mixture:
The several aggregate fractions shall be sized, uniformly graded, and combined in such proportions that the resulting mixture meets the grading requirements of a job mix formula approved by the Department. Aggregates which will not produce a job mix within the full allowable tolerances required by these specifications will be rejected.
When the aggregates are to be used in a plant mix for which a job mix formula has not been previously issued, the Contractor shall submit samples of all aggregates proposed for use in the mix. The aggregate samples shall be taken by the Contractor in the presence of a representative of the Engineer.
Aggregates produced from crystalline limestone, crystalline-dolomitic limestone, or marble shall not be used in the production of open-graded asphalt friction course. When sand asphalt surface course or asphalt concrete surface course is the top or final layer, the amount of coarse aggregate or fine aggregate produced from crystalline limestone, crystalline dolomitic-limestone, or marble shall not exceed 50% of the total amount of coarse aggregate or fine aggregate in the bituminous plant mixed material.
(B) Coarse Aggregate:
(1) General:
Coarse aggregate shall consist of crushed stone, crushed gravel, a mixture of uncrushed gravel with either crushed stone or crushed gravel, or other inert material having similar characteristics. It shall be composed of clean, tough, durable fragments free from an excess of flat or elongated pieces, and shall be free of organic matter and deleterious substances.
(2) Gradation:
The size of aggregate used shall be as required by the specifications or as approved by the Engineer.
(3) Fractured Faces:
For all plant mixes except open-graded asphalt friction course, Type J-1; asphalt concrete binder course, Type HDB; and asphalt concrete surface course, Type HDS, that portion of the coarse aggregate material retained on the No. 4 sieve shall contain at least 60 percent by weight of crushed pieces having 1 or more mechanically induced fractured faces. For open-graded asphalt friction course, Type J-1, that portion of the coarse aggregate retained on the No. 4 sieve shall contain at least 75 percent by weight of crushed pieces having 2 or more fractured faces, and at least 90 percent by weight of crushed pieces having 1 or more mechanically induced fractured faces. For asphalt concrete binder course, Type HDB, and asphalt concrete surface course, Type HDS, that portion of the coarse aggregate retained on the No. 4 sieve shall contain at least 60 percent by weight of crushed pieces having 2 or more mechanically induced fractured faces.
(4) Flat or Elongated Pieces:
Coarse aggregate to be used in open-graded asphalt friction course, Type J-1, shall contain not more than 20 percent of flat and elongated pieces based on the combined total number of both flat and elongated pieces determined by particle count. Flat pieces are those having a ratio of width to thickness of greater than 4. Elongated pieces are those having a ratio of length to thickness of greater than 5.
(5) Soundness:
The maximum weighted average loss shall be 15 percent when subjected to 5 cycles of the soundness test.
(6) Resistance to Abrasion:
Coarse aggregate for all plant mixes except open-graded asphalt friction course, Type J-1; asphalt concrete binder course, Type HDB; and asphalt concrete surface course, Type HDS, shall have a maximum percentage of wear of 55 percent. For open-graded asphalt friction course, Type J-1, the coarse aggregate shall have a maximum percentage of wear of 45 percent. For asphalt concrete binder course, Type HDB, and asphalt concrete surface course, Type HDS, the coarse aggregate shall have a maximum percentage wear of 45 percent unless marine limestone is used, in which case the maximum percentage wear shall be 55 percent.
(7) Clay Lumps:
The maximum percentage by weight of clay lumps shall be 0.3 percent when tested in accordance with AASHTO T112.
(C) Fine Aggregate:
(1) General:
Fine aggregate shall be well graded from coarse to fine and consist of natural sand, stone screenings, or a blend of natural sand and stone screenings. It shall be composed of rough surfaced and angular grains of quartz or other hard durable rock.
(2) Natural Sand:
Sand shall be furnished by the Contractor from sources which have been tentatively approved by the Engineer. Sources which have been contaminated by industrial wastes shall not be used. A sufficient number of samples of fine aggregate, but in no case less than 4, will be taken to indicate any variation within any stockpile or source of supply.
Fine aggregate containing sticks, roots, trash, visible lumps of clay, or other unsatisfactory material shall be cleaned so that the unsatisfactory material is removed before the aggregate is used in the asphalt mixture. The Contractor may utilize any method he desires subject to the approval of the Engineer to clean and condition material for the asphalt mixture.
Natural sand shall be non-plastic when tested in accordance with AASHTO T90.
The total natural sand or sands in the mixture will be tested in accordance with AASHTO T11 to determine the amount of material which can be washed through the No. 200 sieve. The total amount of material which was washed through the No. 200 sieve shall not exceed 4.0% by weight of the total aggregate in the mixture, except that for Type F-1 mixtures, the total amount shall not exceed 6.0%. In addition, for any individual sand the amount of such washed material shall not exceed 12.0% by weight. The above test will be performed prior to establishing the design mix and, when deemed necessary by the Engineer, during production of the mixture.
Natural sand which contains grains of questionable hardness will be subjected to 5 cycles of the soundness test. The weighted average loss shall be not more than 15 percent. The soundness test will be performed prior to establishing the mix design.
(3) Stone Screenings:
Stone screenings shall be so graded that no more than 20 percent by weight will pass the No. 200 sieve when tested by dry sieving in accordance with AASHTO T27.
Stone screenings shall be produced from stone which has a maximum percentage of wear of 55 percent when tested in accordance with AASHTO T96 using test grading A.
When subjected to 5 cycles of the soundness test, the weighted average loss shall be not more than 15 percent.
(D) Mineral Filler:
Mineral filler shall consist of limestone dust, dolomite dust, portland cement, or other inert mineral matter which has been approved by the Engineer. It shall be free from foreign or other objectionable material and shall exhibit a plasticity index of not more than 5. It shall be dry and free from lumps. When flyash is used, the loss on ignition shall not exceed 10 percent by weight of the flyash.
Mineral filler shall meet the following grading requirements when tested in accordance with AASHTO T37:
Sieve Percentage by
Designation Weight Passing
No. 30 100
No. 80 95-100
No. 200 65-100
1012-2 AGGREGATES FOR ASPHALT SURFACE TREATMENT.
(A) General:
The coarse aggregate shall consist of crushed stone, crushed gravel, crushed slag, or other inert material having similar characteristics. All coarse aggregate shall be adequately washed so that it is free from clay, loam, dust, and other adherent materials.
All fine aggregate shall be adequately cleaned so that it is free from sticks, roots, visible lumps of clay, or other unsatisfactory material prior to use.
(B) Gradation:
Coarse aggregate for the mat or seal coat shall be standard size No. 5, No. 6, or No. 78M as required by Table 6601, unless otherwise required by the contract. The aggregate shall meet the applicable gradation requirements of Table 10051.
Aggregate that has become segregated shall be remixed until it will meet the applicable gradation requirements.
(C) Fractured Faces:
That portion of the coarse aggregate retained on the No. 4 sieve shall contain at least 75 percent by weight of crushed pieces having 2 or more fractured faces, and at least 90 percent by weight of crushed pieces having 1 or more fractured faces.
(D) Soundness:
The maximum weighted average loss of either coarse or fine aggregate shall be 15 percent when subjected to 5 cycles of the soundness test.
(E) Resistance to Abrasion:
Crushed stone and crushed slag shall have a maximum percentage of wear of 50 percent. Crushed gravel shall have a maximum percentage or wear of 55 percent.
(F) Blending of Aggregates:
Blending of 2 or more aggregates will not be permitted regardless of the origin of the aggregates if any one of the aggregates fails to meet the requirements for soundness or resistance to abrasion.
(G) Weight of Slag:
Crushed slag shall have a minimum weight of 70 pounds per cubic foot as determined in accordance with AASHTO T19.
Blotting sand shall be fine aggregate consisting of natural sand, commercial sand, manufactured sand, coarse screenings, or other inert material having similar characteristics. The requirements of Subarticles 10122(D) and 101229(F) will be applicable to blotting sand. The fine aggregate shall be adequately cleaned so that it is free from sticks, roots, visible lumps of clay, or other unsatisfactory material prior to use.
Blotting sand shall be standard size No. 1S or 2S meeting the
applicable gradation requirements of Table 10052, or
coarse screenings with 100% passing the 3/8 inch sieve and
not more than 5% passing the No. 200 sieve. As an exception to
the above, when the blotting sand is used over a asphalt curing
seal the material passing the No. 200 sieve shall not be more
than 10%.