FLH PDDM Chapter 9 - Eastern Federal Lands Highway Division

9.4.J. Engineer’s Estimate. (continued)The 1.65 metric tons per cubic meter factor applies to aggregate with a specific gravity of around 2.70.For sources with significantly different specific gravity, it is appropriate to multiply the 1.65 factor by theknown specific gravity divided by 2.70.The quantities for crushed aggregate base usually show on a Tabulation of Quantities Sheet in the plans.Show the rate of application in metric tons or cubic meters per kilometer or per square meter for thebidder's information. Also, specify if the quantities include the 6 percent water additive.Aggregate by the cubic meter = (Average W)(D)(L)(1.33)Aggregate by the metric ton = (Average W)(D)(L)(1.33)(1.65*)(1.06**)Where:W = Width in metersD = Depth in metersL = Length in meters* Metric tons per cubic meter** 6 percent allowance for mixing water where a pugmill is required.When the maximum dry density is available from the lab reports, multiply the compacted volume by thedry density and convert to metric tons.Aggregate by the square meter = (W)(L)If square meter measurement is used, show the exact limits used to arrive at the quantities on the typicalsection. Where measurement is by the square meter, compute the cubic meters or metric tons to providebidders with an application rate.Add a 5 to 10 percent allowance to quantities measured by the metric ton or cubic meter so the bidschedule quantity is an even 500 or 1000 cubic meters or metric tons. Square meter measurements requirevery little allowance as the limits are pretty well predetermined on the Typical Sections. Round up to aneven 1000 square meters for the bid schedule.• Section 302.— Treated Aggregate Courses. Compute quantities for this section similar to Section 301for metric tons or square meters.• Section 303.— Road Reconditioning. Measurement under this section is kilometers or square meters.Use kilometers for mainline work and side roads where widths are relatively constant. Use square metersfor parking areas and other oddly shaped areas or for very small quantities of work.Round kilometers to the nearest 0.01 km for the bid schedule. Add 5 to 10 percent to the square metersto obtain an even 100 or 500 square meters in the bid schedule.• Section 304.— Aggregate Stabilization. Measurement for aggregate stabilization is kilometers or squaremeters. Follow the guidance under Section 303 to compute quantities.Provide an allowance for chemical additives so the bid schedule quantity comes out to an even 10, 50, or100 metric ton quantity.• Section 305.— Aggregate-Topsoil Course. Measurements under this section include metric ton, squaremeter, cubic meter, or meter. Provide an allowance to round the bid schedule amount to an even 10, 100,or 500 units as appropriate.9 - 137