are set according to the proportions obtained in the computation of the final trial blend. Aggregate  Blending  Limits Figure 17-7 is an aggregate grading chart (DD Form 1207), showing the specification limits for the mix and the gradation of the blend when mixed in the proportions shown in figure 17-6A, trial No. 1. Specify Gravity of Bituminous Mix Components A specific gravity data sheet is shown in figure 17-8 (DD Form 1216). This form is used for computing the specific gravity of all the bituminous mix components. If more aggregate fractions are used than are provided for  on  the  form,  additional  forms  may  be  used. Procedures  for  performing  these  tests  are  discussed  in chapter  13  of  this  TRAMAN. Marshall Stability Computations DD Form 1218 (figs. 17-9A and 17-9B) is a data and  computation  sheet  used  in  the  Marshall  stability  test. The specific gravity values of the aggregates and the aggregate  fraction  percentages  from  the  trial  blending furnish  the  information  to  compute  the  fractional weights and to prepare the test specimens. Record the measurements made on the test specimens in the upper right-hand corner of the form. Determine, as described in chapter 13 of this TRAMAN, the stability, flow, unit weight of total mix, and percentage of voids filled with binder to complete the form. Marshall Method Computations Transfer  the  values  from  DD  Form  1218  (figs. 17-9A and 17-9B) for each binder content computation to DD Form 1219 (fig. 17-10). Each graph on the form represents a different test property. Plot the values for each property on their respective graph using the binder contents as ordinates. Draw a smooth curve through the plotted  points. Marshall  Test  Criteria Table   17-7   lists   the   criteria   for   determining optimum  asphalt  content  (OAC).  For  each  test  property, you should consider the type of mix to be used and the expected  load.  The  optimum  bitumen  content  for  each property is designated as a definite point on the curve for that property. The bitumen content percentages (one for each property) are averaged, and the average is used to  read  the  corresponding  value  of  each  test  property. The value, as determined, should be referred to the criteria portion of table 17-7 to see if it is within the permissible   limits   so   that   the   mix   will   perform satisfactorily. Test Variation for Aggregates with 10 Percent or More Larger Than 1-Inch Maximum Size The procedure described in the Marshall method and  the  examples  as  given  in  the  preceding  paragraphs are  applicable  to  hot-mix  design  where  the  amount  of aggregate  larger  than  the  1-inch  sieve  is  less  than  10 percent of the total. When the larger than (plus) 1-inch material  exceeds  10  percent  of  the  total,  the  following variations are made in the procedure: 1. Mix bitumen at the selected content with the entire aggregate,  including  the  plus  1-inch  portion. 2. Pass the mixed hot batch through a 1-inch sieve. Discard the plus 1-inch portion. 3. Make compacted specimens from the portion that passes the 1-inch sieve and perform the Marshall test, except do not calculate the voids of the compacted specimens at this time. 4.  Determine  the  bulk  specific  gravity  of  the  plus 1-inch aggregate, and, with the specific gravity of the compacted specimens, compute the adjusted specific gravity (GA) as follows: where: A =  weight   of   dry,   plus   1-inch   material expressed as a percentage of the total batch weight  (bitumen  plus  aggregate) B =    portion  of  total  batch  remaining  after  the dry, plus 1-inch portion is removed (100%-A%) C    = bulk   specific   gravity   of   plus   1-inch aggregate D    = actual   specific   gravity   of   compacted specimen f =  empirical  factor  =  0.995 17-20