According to Georgia-Inventors.org, the history of concrete goes back to about the first century BC in ancient Greece or Rome. However, commercial concrete block manufacture did not become established until the early 20th century.
Precast Concrete Blocks
Precast concrete blocks began as shapes cast in wooden frames, dried until solid, then laid in mortar. American contractors used these blocks in the mid-1800s.
The Concrete Block Machine
In 1900, Harmon S. Palmer patented a machine that made concrete blocks. Not the first machine to do this, its practical design and durability helped start the modern concrete block industry, according to Pamela H. Simpson, professor of art history at Washington and Lee University.
Improvements to Portland cement, consisting of clay and limestone, also played a role in furthering the concrete block industry. Portland cement acts as the binder in concrete. Additionally, concrete block buildings had their start when H.A. Donald erected the first rock-face concrete block in 1915. This type of building construction continues to this day.