208 ANNUAL REPORT 
SPECIFICATIONS FOR HEAVY -CONCRETE. 
For heavy concrete work, the specifications of Major W. L. Marshall, 
corps of engineers, for the locks in the Illinois and Mississippi canal in 
Illinois will serve as a fair example of United States Engineers’ practice. 
Sections II and III only are quoted as being directly applicable to the 
concrete work. 
II. PROPORTIONS AND MIXING OF CONCRETH. 
II. Proportions and ingredients are measured by volume, and the num: 
ber of cubic feet given below represent the quantities to be used for each 
charge of concrete put into the mixer, 
Portland cement concrete shall in general consist of: 
Rontlandsecenientieeeeeeee erie: 1 part=5 cu. ft.=5 sacks 
Gravieleee Magee ey, ace nara 4 parts=20 cu. ft. 
BrokengStone way wiiaa eee eee 4 parts= 20 cu. ft. 
For the wall supporting the upper gate and in the vicinity of the quoins 
the concréte shall consist of: 
Portland’: CEMeNthres or. eerie nae 6 cu. ft.=6 sacks 
Graviels eS R AO Nb ee 2 epee ence ea 20 cu. ft. 
Brokens Stoners ects sey foe, sce haw 20 cu. ft. 
Natural cement concrete shall consist of: 
INGRAM CSUN ME 5 6 bo50cn00 6c 2 parts= 8 cu. ft.=4 sacks 
Gra Vieliiae ea Oe ee ae 5 parts = 20 cu. ft. 
Brokeny, Stones. eeiecsve seleies 5 parts=20 cu. ft. 
Facing material shall consist of, by volume: 
Portlanducement w.isewa ke Wehr easier caer eae 1 part 
Nornpedomsande:passin'e.NOn oleSiCViCarenieEeirnniriene 3 parts 
12. The piles of gravel and broken stone shall be kept thoroughly 
sprinkled with water to clean surface of dust and to prevent absorption by the 
dry stone of the water used in* mixing the concrete. 
18. When delivered in bags each bag of cement shall be emptied directly 
into the charging box, as the division of a barrel of cement into several bags 
diminishes the chances of injurious effect of a defective barrel, and hence 
the usual requirements of drawing charges from a mixture of five or more 
barrels may be dispensed with. When delivered in barrels this latter require- 
ment will be observed. 
14. All bags and sacks shall be carefully preserved for return to the 
dealers furnishing cement, in order to secure to the United States the rebate 
thereon, to be deducted from subsequent bills for cement. 
15. The proper measures of ingredients shall be emptied into the charg- 
ing box in the following order: ist, gravel; 2nd, cement; 38rd, broken stone: 
4th, water. 
16. Enough water shall be added to make the concrete cohere after a 
thorough mixing. A greater degree of plasticity than that possessed by 
damp sand is required and the object is to have the consistency such that a 
thorough ramming will bring water to the surface. The mass of concrete 
should not quake on ramming; incipient quaking marks the limit, and any 
excess of water in one charge may be corrected by making the next charge 
a little dryer. The proper amount of water can be determined only by exper- 
