Building the foundations of Vicat’s bridge in Souillac, an eyewitness account in 1816

Louis Joseph Vicat’s modest bridge 1812–22 gave rise to modern hydraulic cement. A recently discovered report of its construction reveals the motivation behind Vicat’s life-long research programme. This article is the author’s third study on the work of Louis-Joseph Vicat, a seminal pioneer of material science. The firstFootnote1 dealt with Vicat’s unique ability to synthesise analysis and experimentation, and the secondFootnote2 with his border-crossing approach to scientific and documentary publication, and this one with the first of only two structures that Vicat built, both of which introduced novel material technologies and led to his further career as a research scientist. The 1812–22 masonry Pont de Souillac discussed here employed Vicat’s artificial hydraulic cement for the first time in one of the pier foundations, and the 1827–29 wire-cable Argentat suspension bridge (demolished in 1892) explored the rust-reducing and binding capabilities of hydraulic mortar. The scientific conclusions that Vicat drew from his experience with both structures fuelled his entire career and prepared the construction field for the development of reinforced concrete.