Nanotechnology could further boost the durability and strength of concrete. Researchers with the Canadian National Research Council's Institute for Research in Construction in Canada, believe that nanoscience has a central role to play in producing innovative concretes for the 21st century. In particular, they are developing microscopic particle and fibre admixtures that will improve the porosity control of concrete and, thereby, its durability.
Hydrated cement is porous with a pore size distribution that ranges from the nanometres to millimetres. These pores can allow chloride salts and other chemicals to seep into the concrete.
The addition of nanoparticles will fill these pores.
The researchers are also examining the potential performance benefits of adding nanoscale fibres such as tiny tubes of carbon to the cement mix.
Carbon nanotubes can increase concrete strength by preventing crack propagation in cement composites, making more efficient use of materials.
It is also said that nanotubes can act as nucleating agents, contributing to the increased use of supplementary cementing materials such as fly ash and slag (perhaps through speeding up early hydration, allowing slower-hydrating materials to be more used). This should result in more environmentally sustainable concrete production.