Introduction - Design of Reinforced Concrete - page 4

1.4 HISTORICAL BACKGROUND

Most people believe that concrete has been in common use for many centuries, but this is
not the case. The Romans did make use of a cement called pozzolana before the birth of
Christ. They found large deposits of a sandy volcanic ash near Mt. Vesuvius and in other
places in Italy. When they mixed this material with quicklime and water as well as sand
and gravel, it hardened into a rocklike substance and was used as a building material. One
might expect that a relatively poor grade of concrete would result, as compared with
today's standards, but some Roman concrete structures are still in existence today. One
example is the Pantheon (a building dedicated to all gods) which is located in Rome and
was completed in A . D . 126.
The art of making pozzolanic concrete was lost during the Dark Ages and was not re-
vived until the eighteenth and nineteenth centuries. A deposit of natural cement rock was
discovered in England in 1796 and was sold as “Roman cement.” Various other deposits
of natural cement were discovered in both Europe and America and were used for several
decades.
The real breakthrough for concrete occurred in 1824 when an English bricklayer
named Joseph Aspdin, after long and laborious experiments, obtained a patent for a ce-
ment which he called portland cement because its color was quite similar to that of the
stone quarried on the Isle of Portland off the English coast. He made his cement by taking
certain quantities of clay and limestone, pulverizing them, burning them in his kitchen
stove, and grinding the resulting clinker into a fine powder. During the early years after its
development, his cement was used primarily in stuccos. 1 This wonderful product was
adopted very slowly by the building industry and was not even introduced into the United
States until 1868; the first portland cement was not manufactured in the United States
until the 1870s.
The first uses of concrete are not very well known. Much of the early work was done
by the Frenchmen François Le Brun, Joseph Lambot, and Joseph Monier. In 1832 Le
Brun built a concrete house and followed it with the construction of a school and a church
with the same material. In about 1850, Lambot built a concrete boat reinforced with a net-
work of parallel wires or bars. Credit is usually given to Monier, however, for the inven-
tion of reinforced concrete. In 1867 he received a patent for the construction of concrete
basins or tubs and reservoirs reinforced with a mesh of iron wire. His stated goal in work-
ing with this material was to obtain lightness without sacrificing strength. 2
From 1867 to 1881 Monier received patents for reinforced concrete railroad ties,
floor slabs, arches, footbridges, buildings, and other items in both France and Germany.
Another Frenchman, François Coignet, built simple reinforced concrete structures and de-
veloped basic methods of design. In 1861 he published a topic in which he presented quite
a few applications. He was the first person to realize that the addition of too much water in
the mix greatly reduced concrete strength. Other Europeans who were early experi-

1 Kirby, R. S., and Laurson, P. G., 1932, The Early Years of Modern Civil Engineering (New Haven: Yale
University Press), p. 266.
2 Kirby, R. S., and Laurson, P. G., 1932, The Early Years of Modern Civil Engineering (New Haven: Yale
University Press), pp. 273-275.