And even the weatherproof, fired version is not really considered a satisfactory building material these days. Styrol acrylate dispersions proved the key to his success. At the same time, its bending strength improves by a whopping 300 percent. Sandor is convinced that unfired clay will now enjoy a Renaissance thanks to these research results. Matthias Kroner of BASF's research division on special polymers has succeeded in ringing a new era of concrete technology in much the same way.
Water makes up less than ten percent of the average concrete mixture.
A large portion of this water is needed for hydrating the cement, while the rest serves to make the concrete pliable and ready for processing. Because this part of the water is not bound in the cement, it evaporates during the hardening process, which inevitably leads to a reduction in the concrete's volume. Kroner was able to solve this problem with a polyacrylate-based polymer, whose molecular chains are encased in a solvate sheath. Macroscopically seen, this results in a considerably improved plasticity, as less energy has to be expended on shifting the cement particles against one another. During processing, concrete treated in this way temporarily becomes nearly as liquid as water, after which it proceeds to solidify spontaneously.