Il carattere mutevole e interattivo dei materiali nella storia del costruire

During the past 50 years, technological innovation has changed the design approach to the infinitesimal dimensions of the matter. An unprecedented revolution has already taken place and rewrote some of the pages of the building history. The materials and technologies are invisible to eye but allow to design exceptional levels of performance of many building components. In this way manifests itself a new level of design. The real change modifies the physical and chemical structure of materials and building components. As result we obtain a higher degree of functionalization that responds to outstanding performances. Materials are used at the micrometer and nanometer scale. The new materials can modify their status when the external stimuli from environment or human will change. So materials are defined active and technologies smart, because their performance are changing and interactive. Even the concrete meets innovation hidden in relation to project performance. This report relates to a number of new concretes, starting with the so-called ecological, since adding fly ash and silica fume. The micrometric particles these wastes from industry and the chemical nanometer action of the superplasticizer make self-compacting concrete. After advances in study of polymer chains (1976), synthetic fibers make a micrometer reinforcement so widespread as to contain the shrinkage, in the fiber-reinforced concretes. With the discovery of carbon nanotubes (1991) concretes are armed to the nanometer scale. Are more resistant to traction and have a higher ductility. In particular self-compacting concretes with carbon nanotubes have higher performances and ductile-brittle behavior in the early days of curing. Then there are the concrete with nanoparticles of titanium dioxide, with self-cleaning effect and antipollution, that are smart materials. Titanium dioxide (1967) is made active by light that determines the photocatalysis. It is also used in plasters and paints cement. It is also analyzed the silica airgel, lightweight insulating material (1931). It has a nanoporosity and is also translucent, so it takes in the cavity of windows panes. Last there are phase change materials, nanometric particles in capsules micrometer that enhance the inertia of lightweight components. They are smart materials because when it's hot the heat is absorbed and when it's cold is released. Mutable and interactive performances of these materials allow for life quality and environment respect, pursuing higher comfort level and savings and efficiency energy.