Norwich bulletin., 1918-04-06

crete, made from Portland cement, is now being used in the construction of vessels in more than a dozen lead ing countries of the world and that the United States is the worlds farg- est producer of the materials used in this new form of ship building. The type of vessels now being constructed from concrete range from the barge and floating dock up to the ocean steamer of several. thousand tons ca pacity.
 Concrete made from Portland or other hydraulic cement, reinforced with steel, is the chief material of thees vessels The keel and rigs of the
 vessel are of steel, and. quantities of wire mesh are also in retaining and reinforcing the concrete which fills the spaces between the steel ribs. This combination of concrete and steel has given to this type of work the title of "ferro concrete and reinforced concrete" but in both the chief re- quirements of the new type of vessel,
 concrete and, steel, the United, States far exceeds any other country in it's ordinary. year-to-year production Portland" cement, which gets its
 name from it's resemblance Tn ap- pearance to Portland stone, is produc-
 ed in far greater quantities in the United States than any other coun- try of tho world and in fact probably exceeds that tof all other countries
 combined. Our own output of Port land cement in 1917; was the. largest | in the history of our production, and amounted to 93, ,550, 900 barrels, while that of the other principal cement
 producing countries in the latest A5aaabie year was, Germany 3o,oo0,- 900 barrels, England l7,00e, ,00e barrels, 1 and France s, s,0oo, 900 barrels. Our own
 production has grown with great
 rapidity from 42.000 barrels in 1880 to
 sSS,eo0 in Iss0,l 8,4S2, 900. in, 1900. ss.-
 205, ,0e0 in 1910, and s3,540,000 in 1917, the high record year of production, while the value has grown from $126, 900 in 1880 to s101 .000, 900 in 1917. In the iron and steel required for use in lconjunctions with the cement in ship building, we are also by far the I worlds largest producer, our total out put of pig 2iron, the basis of all iror land steel products. being more thar
 the combined production of any othel
 three countries in the world. a. sl Portland cement, which is scienti. fcal1ys described as "an artificial mix II lure, based on chemical analysis. ol
 limestone and clay, or mari and chalk or shale and limestone" burned to in. Icipient vitrifaction and the cfinkers
 finely ground, hardens when exposed
 to water and is, thus often designated hydraulic cement" though the small. CT quantities designated as natural and "puzzolanic'', cement, are also pro-
 perly included in the term "hydrau
 Ec." The natural cement, madt
 solely from certain classes of lime
 stone, and the ''puzzoIanic" composed i of blast furnace slag and lime, show ; i marked fall-off in production in tht United States in recent years, whil' , the Portland shows a rapid increase , ard, now forms over 95 per cent. of tn ! output of hydraulic cement in tn
 United States, its value amounting il
 1s17ss to s101. .000.0e0 and that of tn "naturalp and 'puzzolanic" less tha, r si, 100000. The census of 1914 show the capital invested in cement manu fracture $2tS, ,485.00O s
 The countries which have airead F utilized concrete for vessel construc | ton in some form include Great Brit r ain, France, Italy. Germany, Neither : lands, Denmark, Norway, Argentina l Brazil. Panama, Australia Canada an the United States the construction ii t the United States of vessels of thi 1 type occurring chiefly at New Yorl Baltimore and San Francisco. Cernen : production in the United States
 widely distributed. occurring in no les : than 2S states, while it's general us ] for docks, piers, reservoirs, irrigatio
 works, tunnels, bridges and pavement
 is even more widely distributed, and it
 use rapidly increasing. The productio
 in the United States is almost exclu ]. sively for domestic use, the export
 having amounted in value to but s, 8 s22 600 in 1913, the high record year
 and $4, ,112, 900 in 1917.