John Esten Park, (1814 - 1872), educated in chemistry and medicine, experimented with using concrete to construct buildings before the American Civil War.
There in Central Texas he found that the materials necessary for concrete production (gravel, sand, lime, and clay) were readily available.
Caliche, thick sedimentary deposits of gravelly clay, lay so close to the surface that it was often dug to make a basement before being used in the concrete mix.
[7] As a general contractor, Park also built the 1850 Guadalupe Male Academy (still standing) and the 1852 Female Department building (long lost).
The non-reinforced concrete gravel-wall method promoted by Park was used in Seguin for 100 or more structures, including cisterns, walls, barns, etc., of which about 20 buildings remain extant.
In it he described the process: "A number of buildings in Seguin are made of concrete thick walls of gravel and lime, raised a foot at a time, between boards, which hold the mass in place until it is solidified.
As the materials are dug from the cellar, it is a very cheap mode of construction, is neat in appearance and is said to be as durable while protected by a good roof, as stone or brick.
The gravel or caliche was pulverized and mixed with sand, portions of burned lime, and water to form a workable slurry.
But the arrival of the railroad in 1876 brought cheap lumber, brick-making equipment, and eventually Portland cement, as its manufacturing methods continued to improve.