Biography

 

After entering Ecole des Ponts in 1806, he was appointed engineer second-class in 1809 in the Dordogne, where he began building the road from Périgueux to Brives.Transferred to the Lot, he was asked to build a bridge on the Dordogne at Souillac in 1812. The task was to build a large bridge with 7 low arches each with a span of 22 m. However, the foundations presented serious difficulties, because of the river flood levels.It was here that Vicat began his observations and research on the chemical composition of mortars.He quickly discovered that these were composed of hydraulic limes, and that the properties of natural hydraulic limes depend on the clay they contain.Over the 10 years of construction of the Souillac Bridge, Vicat searched for a new material capable of setting quickly without water, to replace the slow setting mortar recommended by the Ponts et Chaussées General Council.Like others in the same era, he tried to penetrate the secret of the famous Roman “cement”, capable of hardening without water and resisting it for centuries, as could still be seen in certain structures such as Pont du Gard.Following the observations on limes made in England by Wyalls, Partier and Smeaton, in Sweden by Bagge and in France by Chaptal, he focused his analysis on the properties of the constituents of natural hydraulic binding agents, which he found in caves near Souillac, and far outstripped his contemporaries in synthesising and changing the doses of these elements.In 1817, artificial cement, “grey gold”, was born, and he went on to develop a genuine theory of hydraulicity.In the same year, he also carried out the experiment in the presence of the Academy of Sciences, to silence suspicions.Prony, Gay Lussac and Girard were fulsome in their description of it.In 1818, at the request of the Ponts et Chaussées General Council, he published:“Experimental research on construction limes, concretes and ordinary mortars”, in which he describes the simple but precise manufacture of hydraulic lime, whose qualities surpass those of natural line produced empirically by trial and error, by using a finely ground, mixed and pre-dosed blend of limestone and clay.In 1822, he completed Souillac Bridge, which thus became the first bridge built with artificial hydraulic lime.Charged officially with various assignments relating to the study and manufacture of hydraulic limes around France, he travelled the country in search of deposits of natural hydraulic lime (finding no less than 900 quarries) and to help young engineers in the production of artificial hydraulic limes.In 1824, we find him in Île et Vilaine working on the Brittany canals, and in the Nièvre for the Nivernais canal.

He also invented the “Vicat” needle to measure setting time.In 1827, he became chief engineer first-class for the Isère department, whilst overseeing the construction of the Pont Marie steel wire suspension bridge at Argentat (Corrèze) in 1829. Appointed a corresponding member of the Academy of Sciences in 1833, he won the Statistics prize in 1837 for his work on the composition of substances intended to provide hydraulic limes and cements in the 28 departments of the Rhône and Garonne basins.In 1840, through the discovery of the hydraulicity principles of slow cements (called Portland cements), he produced the clinker that results from baking a mix composed of around 75% limestone and 25% silica at a temperature of 1450°C.

Since he had filed no patent on the cement, in 1845 Parliament voted him an annuity of 6000 Francs in recognition of the savings achieved for the nation, assessed at the time at 182 million Francs, and he was also appointed Commander of the Legion of Honour.Retiring in 1852, having refused the grade of Ponts et Chaussées divisional inspector, in 1856, he published “Practical and theoretical treatise on the composition of mortars, cements and pozzolan coatings and on their use in all sorts of construction, followed by methods of assessing their durability in constructions by the sea”, which sums up the scientific and technical activity that had fascinated him for more than 40 years, and which enabled him to tackle virtually every question relating to hydraulic binding agents.  He had also received a medal of honour at the 1855 Universal Exhibition, and built a bridge in the Grenoble Jardin des plantes, which is the world’s first poured concrete structure.In 1853, his son Joseph (1821-1900), also a Polytechnicien, took part in his father’s research on the chemical causes of the destruction of hydraulic components by seawater and on the method of assessing their resistance to that action.Joseph Vicat built the Vicat company’s first factory at Genevrey-de-Vif, near Grenoble, making natural, artificial and maritime cement, then a second at Grande Chartreuse in la Pérelle for quick cement.

Achievements

• 1812,

  Pont de Souillac

• 1817,

  Natural cement

• 1840,

  Clinker (slow cement)

Awards

• Commander of the Legion of Honour
• Knight of the Order of S.S. Maurice and Lazare de Sardaigne
• Knight of the Read Eagle of Prussia
• Order of Sainte-Anne of Russia

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