Cement is an ancient building material, but its modern form dates back to the 1800s and has facilitated the building of everything from skyscrapers to subterranean shopping malls.
David Saylor, a businessman and co-owner of a cement business in Allentown, Pennsylvania, received the American patent for a new and improved form of cement on this day in 1871. Called “Portland cement” because it resembled the finished stones of Portland in England, where it was first manufactured, this kind of cement is important even today. Portland cement is a key ingredient in concrete, which is today the second-most-consumed material in the world.
Saylor, who originally ran a grocery store, got into cement in 1866, originally producing natural cement–a material developed in the the 1700s. But Saylor was interested in getting into the manufacture of the higher-quality Portland cement, which had been originally been developed in England in the eighteenth and early nineteenth centuries.
At the time, Americans imported Portland cement from England and Germany, the university writes. Portland cement was a better building material than natural cement, writes ExplorePAHistory.com, which meant the first person who could manufacture it in the United States would have a significant business advantage.
Working with a former student from the local university, Saylor developed a process for making Portland cement out of local stone. His product was “in every respect equal to the Portland cement made in England and imported into this country,” he wrote on his patent application.
“His cement received considerable publicity and an award at the Centennial Exhibition in Philadelphia in 1876,“ writes the history website. His company, the Coplay Cement Company, was the sole American manufacturer of Portland cement until 1885–producing around 30 million pounds of the stuff yearly. Today, the historic kilns it used are listed on of the National Historic Places registry.
After Saylor’s death in 1884, his patent didn’t prevent others from also producing the cement and the industry diversified and grew significantly. “At the same time two new technologies were emerging that would lead to rapid growth of the industry: reinforced concrete and the automobile,” writes the history website. Reinforced concrete made it possible to build bridges cheaply; the automobile ensured there was demand for those bridges.
These demands for cement continue today, writes Tim Harford for Citylab. But the demands of producing so much cement come at a cost, he writes, because of a problem that Saylor also faced when developing his cement: the amount of energy it takes to produce Portland cement. Harford writes:
...Concrete is made of sand, water, and cement, and cement takes a lot of energy to produce; the production process also releases carbon dioxide, a greenhouse gas. That might not be such a problem in itself—after all, steel production needs a lot more energy—except that the world consumes absolutely vast quantities of concrete: five tons per person, per year. As a result the cement industry emits as much greenhouse gas as aviation.
While for Saylor, dealing with energy demands meant trying out different kinds of kilns, the modern questions facing cement-producers are a little more intense. The struggle to create more environmentally-friendly cement and update America's legacy cement plants continues.