Researchers from Rice University has created micron-sized calcium silicate spheres, which could provide the ‘building blocks’ for a stronger and low-cost synthetic concrete.
A report by R&D, says the team of researchers formed the spheres in a solution around nanoscale seeds of common detergent-like surfactant.
Rouzbeh Shahsavari, an assistant professor of materials science and nanoengineering at Rice, says cement particles are amorphous and disorganised, making it vulnerable to cracks.
“But with this material, we know what our limits are and we can channel polymers or other materials in between the spheres to control the structure from bottom to top and predict more accurately how it could fracture,” Shahsavari adds.
Researchers controlled the size of the spheres, which were between 100 to 500 nanometres in diameter, by manipulating surfactants, solutions, concentrations and temperatures during the manufacturing process.
Shahsavari believes these are simple but universal building blocks which enable advanced functionalities in synthetic materials.
“Previously, there were attempts to make platelet or fiber building blocks for composites, but this work uses spheres to create strong, tough and adaptable biomimetic materials. Sphere shapes are important because they are far easier to synthesize, self-assemble and scale up from chemistry and large-scale manufacturing standpoints.”
The report reveals: “the team used two common surfactants to make the spheres and compressed their products into pellets, observing that DTAB-based pellets compacted better and tougher, with a higher elastic modulus and electrical resistance than either CTAB pellets or common cement.”
The size and shape of the particles have a substantial impact on the mechanical properties and durability of bulk materials, the article adds.
Shahsavari explains: “It is very beneficial to have something you can control as opposed to a material that is random by nature. Further, one can mix spheres with different diameters to fill the gaps between the self-assembled structures, leading to higher packing densities and thus mechanical and durability properties.”
Manufacturers which increase the strength of cement can use less concrete and decrease the energy needed to make it. In addition, they can reduce the carbon emissions associated with cement production.
The new material is also expected to be more resilient to damaging ions from water and other contaminants because the spheres pack more efficiently than the ragged particles found in common cement. Also, the study found they should require less maintenance and have a longer lifespan.
These spheres could also be used for bone-tissue engineering, insulation and ceramic or composite applications, the report concludes.
This study was published in Langmuir.
