Weltschiffahrt

Bibliographic data

Monograph

Identifikator:: 1831619458

URN:: urn:nbn:de:zbw-retromon-221966

Document type:: Monograph

Author:: Harms, Bernhard http://d-nb.info/gnd/118701657

Title:: Weltschiffahrt

Edition:: Als. Ms. gedr

Place of publication:: Kiel

Publisher:: Schmidt & Klaunig

Year of publication:: 1930

Scope:: 22 S

Digitisation:: 2022

Collection:: Economics Books

Usage license:: Get license information via the feedback formular.

fire-resistive building material of wide application, pro- duces a monolithic unit or structure and permits reinforce- ment with steel to produce additional strength. A little more than half a century ago, nearly all of the portland cement used in America was imported. Since then, production in this country has increased from 170,000 sacks in 1890, to about 390 million sacks in 1920. There are four sacks to a “barrel.” Comparatively little now is imported. “PORTLAND” A DEFINING TERM APPLYING TO A VARIETY OF BRANDS The first use of a material similar to cement for binding together fragments of stone cannot be traced as it extends beyond ancient-written history. But, as already noted, it is known that the Egyptians and Romans prepared a mortar which would harden under water. In 1824, Joseph Aspdin, a bricklayer of Leeds, England, patented an arti- ficial cement which he called “portland” because of its resemblance in color to a building stone obtained from the Isle of Portland, off the coast of England. In the early days, cement was made by a mechanical or physical mixture of various materials or by heating a clayey limestone to a relatively low temperature. Today, different materials first are “mixed” mechanically and then “combined” chemically by intense heat. Cement so made, irrespective of brand, is known as “portland” cement to distinguish it from “natural,” “‘puzzolan” and other cements now little used. What is now the Universal Portland Cement Co. first made a puzzolan cement at the rate of 300 sacks a day. In 1900, it began the manufacture of portland cement and shipped that year 82,000 sacks. Today, the Pittsburgh plant alone has a producing capacity of 44,000 sacks a day while the company’s total capacity is 160,000 sacks a day or 48 million sacks a year.

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