Tim, one of our readers, left a comment about the materials in southern Mexico (60 miles east of Mexico City in the state of Tlaxcala, just outside the state capital) where he’s planning to build an earthbag home. It turns out there’s a wealth of natural building materials nearby that are dirt cheap. In addition to having caliche, which could be used in earthbags straight out of the ground, he also has the primary materials to make geopolymer – piedra caliza (limestone), kaolin clay and sodium carbonate. He will also have to buy lime or make it from scratch.
Geopolymer uses a natural process to convert these loose materials into solid limestone. However, making geopolymer from scratch will likely take a fair amount of time, research and testing. Each material needs to be analyzed so you can determine the appropriate formula. I suggest getting assistance from a local university with a soils testing lab. Win them over by explaining how the abundant local resources (often viewed as undesirable or wastes) can be converted into high value products such as stone houses.
Let’s hope Tim keeps us posted about his project. A little effort could go a long way. It would be great to have a geopolymer earthbag house for evaluation and reference.