François Coignet was a French industrialist of the nineteenth century. He was a pioneer in the development of structural prefabricated and reinforced concrete

Reinforced concrete

Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...

. Coignet was the first to use iron-reinforced concrete as a technique for constructing building structures.

Biography

Coignet, along with his brothers Louis (b. 1819) and Stephane (b. 1820), took over the family business of a chemical plant in Lyon

Lyon

Lyon , is a city in east-central France in the Rhône-Alpes region, situated between Paris and Marseille. Lyon is located at from Paris, from Marseille, from Geneva, from Turin, and from Barcelona. The residents of the city are called Lyonnais....

 in 1846. In 1847 he built some concrete houses using poured cement

Cement

In the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed...

 that was not reinforced with any iron.

In 1851 Coignet decided to settle near Paris, in the Saint-Denis

Saint-Denis

Saint-Denis is a commune in the northern suburbs of Paris, France. It is located from the centre of Paris. Saint-Denis is a sous-préfecture of the Seine-Saint-Denis département, being the seat of the Arrondissement of Saint-Denis....

 neighborhood. There in 1852 he opened a second plant where he obtained a patent for cement clinker

Clinker (cement)

thumb|200px|right|Typical clinker nodulesthumb|200px|right|Hot clinkerIn the manufacture of Portland cement, clinker is lumps or nodules, usually 3-25 mm in diameter, produced by sintering limestone and alumino-silicate during the cement kiln stage.-Uses:...

. Coignet then built a cement factory there using exposed lime walls. He followed the pisé de terre system, rammed earth method of construction, in building the plant. This was his first time he worked with this method in concrete. Later he took out a patent in England entitled "Emploi de Beton" which gave details of his construction techniques.

Coignet started experimenting with iron-reinforced concrete in 1852 and was the first builder ever to use this technique as a building material. He decided as a publicity stunt

Publicity stunt

A publicity stunt is a planned event designed to attract the public's attention to the event's organizers or their cause. Publicity stunts can be professionally organized or set up by amateurs...

, and for promotional purposes of his cement business, to build a house made of béton armé, a type of reinforced concrete. In 1853 he built the first iron reinforced concrete structure anywhere, a four story house at 72 rue Charles Michels. This location was near his family cement plant in St. Denis, a commune

Communes of France

The commune is the lowest level of administrative division in the French Republic. French communes are roughly equivalent to incorporated municipalities or villages in the United States or Gemeinden in Germany...

 in the northern suburbs of Paris. The house was designed by local architect Theodore Lachez.




This house was inspected in 1855 by a committee of fourteen architects led by Henri Labrouste

Henri Labrouste

Pierre François Henri Labrouste was a French architect from the famous École des Beaux Arts school of architecture. After a six year stay in Rome, Labrouste opened an architectural training workshop, which quickly became the center of the Rationalist view...

. In Labrouste’s report he said that all the work for the house was done entirely of cement and artificial stone. It also showed that Coignet made use of different materials of little value and mixed with lime and water to make decorative moldings and cornice

Cornice

Cornice molding is generally any horizontal decorative molding that crowns any building or furniture element: the cornice over a door or window, for instance, or the cornice around the edge of a pedestal. A simple cornice may be formed just with a crown molding.The function of the projecting...

 that crowned the building. The railing was also a molded concrete mass. He had taken out a patent in March of that year entitled Béton Économique which showed how inexpensive aggregates

Construction Aggregate

Construction aggregate, or simply "aggregate", is a broad category of coarse particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates. Aggregates are the most mined material in the world...

 could be used in concrete. He then proceeded to build several more concrete houses that still stand to this day.

This report showed that Coignet made a concrete mixture of ash

Wood ash

Wood ash is the residue powder left after the combustion of wood. Main producers of wood ash are wood industries and power plants.-Composition:...

 and slag

Slag

Slag is a partially vitreous by-product of smelting ore to separate the metal fraction from the unwanted fraction. It can usually be considered to be a mixture of metal oxides and silicon dioxide. However, slags can contain metal sulfides and metal atoms in the elemental form...

 with lime

Calcium oxide

Calcium oxide , commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline crystalline solid at room temperature....

 and used the mud

Mud

Mud is a mixture of water and some combination of soil, silt, and clay. Ancient mud deposits harden over geological time to form sedimentary rock such as shale or mudstone . When geological deposits of mud are formed in estuaries the resultant layers are termed bay muds...

 in rammed earth method of construction. The report said it had doubts of the soundness of Coignet's techniques and that it could be dangerous. The house has been abandoned for many years and squatters have taken over the property from time to time. While it has deteriorated, it still stands going into the twenty-first century - some 150 years later! The now famous house, classed as a world patrimony

National patrimony

The store of wealth or accumulated reserves of a national economy. The term often refers to a nation's non-monetary wealth or reserves, such as its artistic heritage.- China :...

,
has been classified a historical monument since 1998.

Coignet had an exhibit at the 1855 Paris Exposition

Exposition Universelle (1855)

The Exposition Universelle of 1855 was an International Exhibition held on the Champs-Elysées in Paris from May 15 to November 15, 1855. Its full official title was the Exposition Universelle des produits de l'Agriculture, de l'Industrie et des Beaux-Arts de Paris 1855.The exposition was a major...

 to show his technique of reinforced concrete. At the exhibit he forecasted that the technique would replace stone as a means of construction. In 1856 he patented a technique of reinforced concrete using iron tirants

Rebar

A rebar , also known as reinforcing steel, reinforcement steel, rerod, or a deformed bar, is a common steel bar, and is commonly used as a tensioning device in reinforced concrete and reinforced masonry structures holding the concrete in compression...

. In 1861 he put out a publication on his techniques.

Coignet is the inventor of moulded concrete which is known as Béton Coignet. He had much success at building with this type of concrete. He became a renowned building contractor and showed his many designs, including the molded concrete church of Le Vesinet

Le Vésinet

Le Vésinet is a commune in the Yvelines department in the Île-de-France in north-central France. It is located in the western suburbs of Paris from the center....

 near Paris. This church with its 130 foot spire is the first modern monumental building built in concrete.

Construction projects

One of Coignet's largest projects was the eighty seven miles of "aqueduct de la Vanne" (Paris metropolitan water supply) with over four miles of arches of over 100 foot high spans. He built the aqueduct

Aqueduct

An aqueduct is a water supply or navigable channel constructed to convey water. In modern engineering, the term is used for any system of pipes, ditches, canals, tunnels, and other structures used for this purpose....

 between 1867 and 1874.


Coignet also helped construct the lighthouse of Port Said

Port Said

Port Said is a city that lies in north east Egypt extending about 30 km along the coast of the Mediterranean Sea, north of the Suez Canal, with an approximate population of 603,787...

 (Egypt) and the high retaining walls of the Passy Cemetery

Passy Cemetery

The Passy Cemetery is a famous cemetery located at 2, rue du Commandant Schlœsing in Passy, in the 16th arrondissement of Paris, France.-History:...

 and Trocadéro Cemetery

Trocadéro

The Trocadéro, , site of the Palais de Chaillot, , is an area of Paris, France, in the 16th arrondissement, across the Seine from the Eiffel Tower. The hill of the Trocadéro is the hill of Chaillot, a former village.- Origin of the name :...

 in Paris.







Coignet built sea wall at Saint-Jean-de-Luz

Saint-Jean-de-Luz

Saint-Jean-de-Luz is a commune in the Pyrénées-Atlantiques department in south-western France.Saint-Jean-de-Luz is part of the province Basque of Labourd and the Basque Eurocity Bayonne - San Sebastian .-Geography:...

(1857–1893)