Bridges presentation
poured form. The discovery of natural cement in 1796, on the Isle of Sheppey in the Thames Estuary
(UK), renewed interest in the material, but the age of concrete began its most vigorous development
with Joseph Aspdin's invention in 1824 of artificial Portland cement. This mixture of clay and
limestone, calcined and ground, resulted in a material having broad application for buildings and
bridges. The scientific studies of Vicat on natural and artificial cements initiated in 1816 at the Pont
de Souillac (France) revealed the first understanding of the chemical properties of hydraulic cement.
Canvass White, an engineer on the Erie Canal (USA), discovered natural cement in 1818 and
established a mill to manufacture the substance at Chittenango, New York. The primary benefit of
the material was its ability to set under water. Naming it hydraulic cement, he patented the process
in 1819 and used it for aqueducts, abutments, culverts, and lock walls.
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