Nano-cements

Everyday materials are the result of century-long optimization, yet, common cement formulations have so far escaped preparation as nanoparticles. Modifications of the presently used flame processes for preparation of white pigment and carbon black have now enabled preparation of nano-cements. These tiny particles are extremely active and react within minutes while traditional cements harden over several weeks.Cements are literally what our technical society is built upon. Manufactured at over 2.4 Gigatons per year, Portland cement is the largest volume chemical produced worldwide. Building construction relies on this reactive material’s ability to recrystallize and hydrate, forming a complex mixture of calcium and aluminum silicates. Since this process depends on the available surface area, it is slow for micron-sized cement particles – an observation known from the rate at which typical building construction progresses.

Researches at the ETH Zurich in Switzerland have now developed a one-step process to manufacture typical Portland cements in the form of nanoparticles. Their small size enables the traditionally sluggish cement hardening to speed up and cement pastes solidify within minutes. This accelerated hardening is a dramatic example of how particle size can affect the properties of well-known commodity materials. At present, these ultra-fast nano-cements are being evaluated for applications in building renovation, sealing and as an accelerating additive to presently used cements. The nano-cement’s current porosity, however, demands further process improvements before the material can be used in harsh load bearing applications.