This is Roald Tweet on Rock Island.
It's there, everywhere. Our skyscrapers rest on it, it lies under the wheels of our cars from New York to San Francisco, but I don't suppose your average person thinks about concrete more than once a week or so.
Yet, like everything humans have made, concrete has a story, a drama, characters, a stage. It has scenes, too, and one of these crucial scenes in the story of concrete used Rock Island as its stage.
The year is 1890. Congress has just authorized the Corps of Engineers to build a canal from Rock Island east to the Illinois River in order to give our valley direct access to Chicago markets. The powerful railroad lobby was not happy with this news and succeeded in getting Congress to reduce the width of the canal to thirty feet—much too narrow for existing boat traffic.
In charge of the project was a young Major, William L. Marshall. Marshall proposed a daring experiment. He would use poured concrete to make the lock walls rather than the traditional cut stone and save enough money to increase the width back to thirty-five feet. This had never been done before. Concrete was used only to cement bricks and stones together. Major Marshall also proposed using American cement for his concrete rather than imported cement currently in construction. Contractors believed Portland cement to be inferior.
Permission was granted. Marshall devised giant new equipment to mix and form the concrete, which had to be poured all at once.
So successful were the lock walls that poured concrete was used in a new lock under construction at the upstream tip of Rock Island.
Neither the canal to Chicago nor the lock at Rock Island proved commercially successful, but the experiments in the use of poured concrete here revolutionized the American construction industry. The grades Marshall established for Portland cement became standard in the industry. Marshall's experiments also helped make possible the construction of a far more successful canal a few years later, further south—in Panama.
Rock Island Lines with Roald Tweet is underwritten by Augustana College, Rock Island, Illinois.
