It has been an interesting month as the country starts coming back to “normal”. I was fortunate to have the opportunity to “attend” (virtually) a presentation by a University of Texas at Austin professor. Professor Hugh Daigle provided a very informative presentation on “Nanotechnology for Upstream Oil and Gas Operations”. [Ref. 1] Whether you are interested in Oil and Gas or not, there are some very interesting points that are important where your nanotechnology interests are. The reference is to a YouTube video of the presentation.
The presentation starts out with establishing the baseline of what is nanomaterial. The slide at roughly 7:35 of the presentation presents why nanoparticles are so interesting. This is followed by covering the forces that are important to consider at the small scale. Most are aware of Electrostatic and van der Waals forces. The Steric forces are not mentioned as much as the two previous ones. The description of the application is interesting and has a good explanation of applications.
Jumping forward to roughly 22:24 in the presentation the explanation of controlling nanoparticle surface charges is important to improving the properties of cement. At roughly 25:30, he goes into an explanation of why this sizing of the nanoparticles can improve the properties of the cement.
Daigle’s presentation fits into an special area of my interest. We know that the Roman Coliseum is still standing after 2,000 years. We can not duplicate their efforts. Research has been done and there are some interesting findings. Reference 2 has the explanation that has been acccepted without too much understanding. Basically, the Roman cement was superior due to using volcanic ash from the regions around the Gulf of Naples. Also, it is known that the Roman cement cures under water, salt water to be precise.
The work reported in Nature by Alexandra Witze [Ref. 3] has taken this a step further. A team headed by Marie Jackson discovered there is a very rare mineral formed in the Roman cement. [Ref. 4] This mineral, aluminum tobermorite comes from a silicate mineral, phillipsite, which is common in volcanic rocks. Their finding also identified crystals of aluminum tobermorite growing from it. Apparently the tobermorite is grown from phillipsite by the action of salt water washing through the cement. This increases the alkalinity of the cement. It is a rare material. The tobermorite strengthens the cement due to a plate-like structure that permits flexure not observed in today version of cement.
Now, I come back to Professor Daigle’s presentation. He talked about the size of the nanoparticle has a significant influence of the strength of the cement. To me the question I have is did the Romans develop a process that created a consistent size of nanoparticle that yielded the optimum size for the most strong cement?
For the doubters that think the Romans would not have sufficient knowledge/understanding to know that they needed a certain size material (nanoparticle), consider this fact. In the Middle Ages, the artisans knew they needed a certain size gold nanoparticle to create the red coloring in stain glass windows. Did they call it gold nanoparticles? Of course not, but there had to be a process, probably milling, that after a certain time of processing yielded the proper size material to create the red color. It is possible that the Romans could have had a similar process for the phillipsite.
It does provide some interesting questions about the capability of the Romans and their cement.