| People have used concrete since ancient times, but | | | | In 1868, the Frear Stone Manufacturing Co. of |
| the concrete block machine was not invented until | | | | Chicago began manufacturing G.A. Frear's patented |
| the 1830s. Widespread manufacture of concrete | | | | concrete blocks with decorative trim, less expensive |
| blocks began in the early 1900s, and their popularity | | | | than carved stone. This was the first commercial |
| grew rapidly. Since then, they have been used in an | | | | manufacture of concrete block, and many of these |
| enormous number of projects including basement | | | | blocks survived the 1871 Chicago fire. |
| walls, commercial buildings and more. | | | | Effects |
| History | | | | Improvements to Portland cement and its falling cost, |
| Ancient Romans or Greeks are traditionally | | | | along with a newly invented machine, revolutionized |
| considered the inventors of concrete from around | | | | the concrete industry in the early 1900s. This |
| the first century B.C., constructing it from lime, | | | | cast-iron machine constructed hollow concrete blocks |
| volcanic sand and ash, small stones, and water. | | | | and made widespread production possible. Harmon |
| Romans used concrete extensively in structures such | | | | Palmer obtained his patent in 1900, and within 10 |
| as the Pantheon, the interior of the Coliseum and | | | | years, over a thousand companies and individual |
| aqueducts. | | | | contractors were making hollow concrete blocks. |
| Time Frame | | | | Considerations |
| The first precast concrete blocks were cast in | | | | Thousands of concrete-block houses were built |
| wooden frames, dried like bricks into a solid form, | | | | through the 1920s in the U.S., most in the Midwest, |
| and then laid in mortar like bricks, as well. Many | | | | perhaps because of the abundant sand and gravel |
| individual contractors were creating these precast | | | | there. The houses were advertised as being fireproof |
| blocks by the mid-1800s. The first house in the | | | | and weatherproof. Concrete-block structures are still |
| United States built entirely of these blocks was | | | | common today for commercial buildings, silos and |
| constructed in 1837 on Staten Island, New York. | | | | basement walls. |
| Types | | | | Theories/Speculation |
| In 1824, an English inventor named Joseph Aspidin | | | | Scientists at Massachusetts Institute of Technology |
| invented a style of cement, a modified form of | | | | are studying whether the Egyptians might have used |
| which is still the dominant type in construction today. | | | | concrete brick machine in the pyramids. If so, this |
| It was made of powdered limestone and clay mixed | | | | would change the entire accepted history of |
| with water. Aspidin named Portland cement after a | | | | engineering. Concrete would have been invented at |
| type of building stone that was quarried on the Isle | | | | least 2,000 years before it has traditionally been |
| of Portland in Dorset, England. | | | | thought, and historians also have theorized the |
| Reinforced concrete brick machine, which includes | | | | pyramid blocks were carved whole from quarry |
| embedded metal, was invented in 1849 by Joseph | | | | stones. They have assumed the blocks were hauled |
| Monier, although he did not receive a patent until | | | | from other locations by slaves and additional |
| 1867. | | | | workers, rather than being constructed on-site. |
| Significance | | | | |