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IF KI 7 e I IN k NeiI INx n. v3 N F4t . � ell .., . r . . . y. ^ . IN s v .. , , .3 a3., ; ' ^'N. , .�7 . . NN a S 7 330-5 .2 Prevention of Segregation : Form and maintain stockpiles in a manner that will prevent segregation . If a stockpile is determined to have excessive segregation, the Engineer will disapprove the material for use on the project until the appropriate actions have been taken to correct the problem . Fee 330-5 .3 Blending of Aggregates : Stockpile all aggregates prior to blending or placing in the cold hoppers . Place all aggregates to be blended or proportioned in separate bins at the cold hopper. Proportion by means of securely positioned calibrated gates or other approved devices . 330-5.4 Cold Bins : 330-5.4. 1 Adequacy of Bins : Use separate bin compartments in the cold aggregate feeder that are constructed to prevent any spilling or leakage of aggregate from one bin to another. Ensure that each bin compartment has the capacity and design to permit a uniform flow of aggregates . Mount all of the bin compartments over a feeder of uniform speed, which will deliver the specified proportions of the separate aggregates to the drier at all times . If necessary, equip the bins with vibrators to ensure a uniform flow of the aggregates at all times . 330-5 .4 .2 Gates : Provide each bin compartment with a gate which is adjustable in a vertical direction . Provide gates that can be held securely at any specified vertical opening . Equip the gates with a measuring device for measuring the vertical opening of the gates from a horizontal plane level with the bottom of the feeder. 330-5.5 Mineral Filler : If mineral filler is required in the mix, feed or weigh it in separately from the other aggregates . in 330-5 . 6 Heating and Drying : Heat and dry the aggregates before screening . Control the temperature of the aggregates so that the temperature of the completed mixture at the plant falls within the permissible range allowed by this Section . 330-5 . 7 Screening Unit : 330-5 . 7. 1 Oversize Aggregate : Remove any oversized pieces of aggregate by the use of a scalping screen . Do not return this oversized material to the stockpile for reuse unless it has been crushed and reprocessed into sizes that will pass the scalping screen . 330-5 . 7.2 Screening : Ensure that the quantity of aggregates being discharged onto the screens does not exceed the capacity of the screens to actually separate the aggregates into the required sizes . Allow up to a maximum of 10 % plus .... 10 material in the minus - 10 bin . The Engineer will determine the maximum amount of minus - 10 material allowed in the IF plus40 bins , in accordance with its effect on the uniformity of the mix . 330-6 Preparation of the Mixture. 330-6. 1 Batch Mixing : 330-6. 1 . 1 Aggregates : Once the dried aggregates and mineral filler (if required) are prepared in the manner previously described and combined in batches to meet the verified mix design by weighing each separate bin size, convey them to the empty mixer. 330-6. 1 .2 Asphalt Binder : Introduce the accurately measured hot asphalt binder into the mixer simultaneously with, or after, the hot aggregates . Continue mixing until the mixture is thoroughly uniform with all particles fully coated . 330-6 . 1 .3 Mixing Time : The mixing time begins when the measuring devices for both the asphalt and the aggregates indicate that all the material is in the mixer, and continues until the material begins to leave the mixing unit. Since the mixing time varies in relation to the nature of the aggregates and the capacity of the mixer, mix sufficiently to produce a thoroughly and uniformly coated mixture . - 70 - FPID ( S ) : 423186 - 1 - 58 - 01 Ile 't 51 IN I In I IN IF In 77777W77777 T"Wpw ,,- IN