Fig. 69.—Sketch Plans of Concrete Making Plant for Battery Emplacement.
A batch made up as follows, tamped in place to a volume of 30 cu. ft. or 1-1/9 cu. yds.:
| 1 bbl. cement, at $2.532. | $ 2.532 |
| 0.315 cu. yd. shells, at $0.481. | 0.151 |
| 0.51 cu. yd. sand, at $0.25. | 0.130 |
| 0.89 cu. yd. stone, at $3.047. | 2.710 |
| Mixing and placing. | 0.761 |
| ———— | |
| Total for 30 cu. ft. | $ 6.284 |
This gives a cost per cubic yard of concrete in place as follows:
| Concrete in place, per cu. yd. | $ 5.655 |
| Forms, per cu. yd. of concrete. | 0.220 |
| ———— | |
| Total cost of concrete per cu. yd. | $ 5.875 |
United States Fortification Work.—The following methods and cost of mixing and placing concrete by hand and by cubical mixers is given by Mr. L. R. Grabill for U. S. Government fortification work done in 1899.
Hand Mixing and Placing.—The work was done by contract, using a 1 cement, 2 sand, 2 pebbles and 3 stone mixture turned four times. A board large enough for three batches at a time was used; one batch was being placed, one being mixed and one being removed at the same time so that the mixers moved without interval from one to the other. Two gangs were worked, each mixing 64 batches of 0.75 cu. yd., or 48 cu. yds. of concrete per day at the following cost:
| Hand Mixing 9,000 Cu. Yds.— | Per day. | Per cu. yd. |
| 6 men wheeling materials | $ 7.50 | $0.16 |
| 8 men mixing | 10.00 | 0.21 |
| 8 men wheeling away | 10.00 | 0.21 |
| 6 men placing and ramming | 7.50 | 0.16 |
| 1 pump man | 1.25 | 0.02 |
| 1 waterboy | 1.00 | 0.02 |
| 1 foreman | 2.00 | 0.04 |
| ——— | ——— | |
| Totals | $39.25 | $0.82 |
The entire cost of plant for this work was about $500.