Figure 17-4.—Retaining wall.to be poured, adding a waste factor, and multiplying thisvolume times the amount of each component in the1-cubic-yard mix design. The manner of doing this isdescribed in the following example.Example Problem: Using the mix design deter-mined previously in this chapter, determine the totalamount of materials needed to construct the75-foot-long retaining wall shown in figure 17-4. The1-cubic-yard mix design is recapped below.Cement:6.49 sacks (Type IA)Water36.6 gallonsCoarse aggregate:1,735.0 poundsFine aggregate:1,153.0 poundsAir content:5.0 percentTo determine the total quantity of each of the aboveingredients needed for the retaining wall, you must firstcalculate the total volume of concrete required. As youshould know by now, an easy way to do this is to breakthe retaining wall into simple geometric shapes and thendetermine and accumulate the volumes of those shapes.Since you should know how to do this, we will simplysay that the total volume of the retaining wall is 63.7cubic yards. To this figure you add a 10-percent waste17-10factor so that the adjusted amount of concrete neededfor the project is 70.07 cubic yards. (Had the initialvolume needed been greater than 200 cubic yards, youwould have used a 5-percent waste factor.)Now that you know the total amount ofconcrete needed, you can determine the totalquantity of each of the concrete ingredients bysimply multiplying the amount of each ingredientneeded for 1 cubic yard by the total amount ofconcrete required for the retaining wall. As anexample, you need 1,153 x 70.07 = 80,790.7 pounds,or 40.4 tons, of fine aggregate for the retaining wall.The other ingredients are computed in the same way.That being done, you find that the followingquantities of ingredients are need for the project:Cement:455.0 sacks (Type IA)Water:2,567.0 gallonsCoarse aggregate:60.8 tonsFine aggregate:40.4 tonsBITUMINOUS MIX DESIGNHot-mix bituminous concrete for pavements is amixture of blended aggregate filled with bituminouscement binder. The materials are heated while beingmixed to promote fluidity of the bitumen for thoroughcoverage of the aggregate particles. The design of abituminous concrete mix consists of the determinationof an economical blend and gradation of aggregatestogether with the necessary content of bituminouscement to produce a mixture that will be durable, havethe stability to withstand traffic loads, and be workablefor placement and compaction with the constructionequipment available.The procedures described in this section areperformed during the design of a hot-mix bituminousconcrete. They include testing, plotting the results ongraphs, and checking the readings against values fromthe design tables. Testing of the ingredients and the mixis started before and continued throughout the pavingoperations. Specific test procedures are not covered inthis discussion; instead, you should refer to chapter 13of this TRAMAN and to Materials Testing,NAVFAC MO-330.

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