An Almost-Forgotten Chapter in the History of Concrete
For some years before the Civil War, this frontier town was a center of experimentation with concrete. At least two citizens had their own formulas and competed for contracts to put up some large structures. Dr. John E. Park, a Georgia-born physician and chemist who moved here in the late 1840s, was one of them. Years before Portland cement was patented, he had developed and patented his own formulas for "limecrete" that used materials obtained locally.
Teams of slaves dug gravel and caliche on site, and brought sand and water from nearby streams. These were mixed with trace ingredients like clay and ash, and with lime produced from Hill Country limestone, and brought by wagon from San Marcos. The resulting material was not so different from the adobe bricks widely used in West African buildings. But the construction technology was decidedly American.
The African-American workers poured the mix into wooden forms they had built, about a foot high and from one to two feet wide. These forms were joined by iron rods to keep them from spreading apart, and held the set width apart by oak rods. When a layer hardened in about a week, the forms were raised and another layer poured. The iron rods were driven out and used again. The oak rods remained embedded in the thick concrete walls. This process required skilled labor to get the proportions just right, and if it was too hot or too cold, too wet or too dry, the concrete would not set properly. But it was well worth the effort. The resulting load-bearing limecrete walls were solidly insulated and fireproof, and when whitewashed or painted, the buildings glowed like marble temples amid the log cabins and timber buildings of the raw frontier community.
Remarkably, by the time of Park's death in 1872, this town, with a population of less than 1,000, had almost 90 concrete buildings - houses, churches, even the courthouse and other public buildings. And countless structures such as cisterns, fences, animal pens, retaining walls, and so forth were made of what was traditionally called "Park's concrete."
No other place in the U.S. is known to have had such an extraordinary concentration of concrete buildings by the late 19th century. Indeed, no other place claims to have had more of them, though it is possible (but almost unknowable) that some big city back East may have had a higher total.
The arrival of the railroad in 1875, bringing in cheap lumber and other materials, and the establishment of several brickworks around town, made homes of concrete unfashionable even in Seguin. Today, only about 20 of the limecrete relics survive here. Sadly, every so often, another one of these irreplaceable artifacts is destroyed.