Portland cement is used because it is the only kind adapted to general
construction. Other cements are manufactured but they possess individual
characteristics that restrict their use. The word Portland is not a trade
name, but signifies the kind and distinguishes it from the slag, natural,
and other cements.
A number of brands of Portland cement are manufactured, most of which
are made to meet the requirements of a fixed standard adopted by the
United States Government and the American Society for Testing Materials.
Cement always should be tested for use in important work, but this is
impractical for the user of small amounts and it is generally safe
practice to omit the test if a reliable brand of Portland cement
of American manufacture is selected, especially if the dealer's or
manufacturer's guaranty that it meets the standard is secured.
The following simple test for soundness is easily made and is on the side
of caution. Make a ball, about 1-1/2 inches in diameter, if neat cement
and water; place it under a wet cloth and keep it moist for 24 hours,
then put the ball in a vessel of water; allow the water to come to the
boiling point slowly and to boil for 3 hours. A good cement will not be
affected, but an inferior one will check, crack, or go to pieces entirely.
Portland cement is shipped in paper bags, cloth sacks, and wooden barrels
(sometimes in bulk). For the average user the cloth sack is the best
container, as it is easier to handle; and while the manufacturers charge
more for this kind of package, they allow a rebate for the return of the
sacks in good condition. A sack of Portland cement weighs 94 pounds and a
barrel contains the equivalent of four sacks.