Engineering and Contracting . by making the every case the sand and. stone were broughtonto the job separately. .A large number oftests were run on both sand and stone to de-termine: (1) the per cent of voids, (2) theper cent of clay or silt, (3) the per cent ofsilicious material in the sand, and (4) thenature of the stones composing the larger ag-gregate. These tests were made before thework was commenced and from time to timeupon samples obtained from the job. Thesand was graded from Vi in. down to notmore than 3 per cent passing a 100 meshscreen. The larger aggregate was in mostcases graded
Engineering and Contracting . by making the every case the sand and. stone were broughtonto the job separately. .A large number oftests were run on both sand and stone to de-termine: (1) the per cent of voids, (2) theper cent of clay or silt, (3) the per cent ofsilicious material in the sand, and (4) thenature of the stones composing the larger ag-gregate. These tests were made before thework was commenced and from time to timeupon samples obtained from the job. Thesand was graded from Vi in. down to notmore than 3 per cent passing a 100 meshscreen. The larger aggregate was in mostcases graded from Wz ins. to % in. It is be-lieved that unless the aggregate is thoroughlytested, poor results are liable to be obtained. In all cases the cement was furnished tothe contractors by the county, contracts beingentered into with local dealers for furnishingand delivering cement on the jobs. Carefulattention was given to the care of emptycement sacks. In all cases these were tiedinto bundles of .iO, each witli a tag attached. Fig. 4. Method of Setting Forms and Supplying Water to the Concrete Mixer. conrrcie thicker in the center of the material for the earth shoulders wasthrown up m a windrow along the berm of showing the name of the dealer furnishing thecement, the name and number of the road andjthe name of the contractor. Lost cement sacks; Alav 13. l)14. Engineering and Contracting 553 I amDiinted to only IV2 per cent of the total niimlier used. rranstorhilion of Mulcrials.—One of thegreatest problems in country road work is the I transportation of materials to the job. A con-tinuous rain will often delay the work for I 24 hours or even longer, whereas in the city I haulinif may be commenced immediately afterthe rain. The methrd of haiding was quite
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