Over the last week or so there’ve been a number of articles and publications about cement and concrete and nanotechnology. The Dec. 17, 2012 Nanowerk Spotlight article by (Mohammed) Shakeel Iqbal and Yashwant Mahajan for India’s Centre for Knowledge Management of Nanoscience & Technology (CKMNT, an ARCI [International Advanced Research Centre for Powder Metallurgy and New Materials] project, Dept.of Science & Technology) seemed to kick off the trend with a patent analysis of nanotechnology-enabled cement innovations,
China is the world leader of patent filings, their 154 patent applications contributing 41% of overall filings, representing the major and active R&D player in the area of nano-based cementitious materials. South Korea is the second leading country with 55 patents (15% of patent filings) on nano-enabled cement, closely followed by United States with 51 patents. Russia, Germany, Japan, France and India are the other leading patent filing countries with 37, 18, 11, 9 and 5 patents respectively, while the remaining patents represent a minor contribution from rest of the world.
Dagestan State University (Russia) is the leading assignee with 15-patents to its credit, which are mainly focussed on the development of heat resistant and high compression strength concrete materials. Halliburton Energy Services Inc (USA) comes second with 14-patents that are directed towards well bore cementing for the gas, oil or water wells using nano-cementitious materials.
This is another teaser article from the CKMNT (see my Dec. 13, 2012 posting about their bio-pharmaceutical teaser article) that highlights the findings from a forthcoming report,
A comprehensive Market Research Report on “Nanotechnology in Cement Industry” is proposed to be released by CKMNT in the near future. Interested readers may please contact Dr. Y. R. Mahajan, Technical Adviser and Editor, Nanotech Insights or Mr. H. Purushotham, Team Leader [email protected]
Regardless of one’s feelings about patents and patent systems, the article also provides a good technology overview of the various nanomaterials used as fillers in cement, courtesy of the information in the filed patents.
A December 20, 2012 news item on Azonano points to at least of the reasons cement is occasioning research interest,
Cement production is responsible for 5% of carbon dioxide emissions. If we are to invent a “green” cement, we need to understand in more detail the legendary qualities of traditional Portland cement. A research group partly financed by the Swiss National Science Foundation (SNSF) is tackling this task.
The Dec. 20, 2012 Swiss National Science Foundation (SNSF) news release, which originated the news item on Azonano, goes on to describe the research into exactly how Portland cement’s qualities are derived,
The researchers first developed a packing model of hydrated calcium silicate nanoparticles. They then devised a method for observing their precipitation based on numerical simulations. This approach has proven successful (*). “We were able to show that the different densities on the nano scale can be explained by the packing of nanoparticles of varying sizes. At this crucial level, the result is greater material hardness than if the particles were of the same size and it corresponds to the established knowledge that, at macroscopic level, aggregates of different sizes form a harder concrete.” [said Emanuela Del Gado, SNSF professor at the Institute for Building Materials of the ETH Zurich]
Until today, all attempts to reduce or partially replace burnt calcium carbonate in the production of cement have resulted in less material hardness. By gaining a better understanding of the mechanisms at the nano level, it is possible to identify physical and chemical parameters and to improve the carbon footprint of concrete without reducing its hardness.
For those of a more technical turn of mind, here’s a citation for the paper (from the SNSF press release),
E. Masoero, E. Del Gado, R. J.-M. Pellenq, F.-J. Ulm, and S. Yip (2012). Nanostructure and Nanomechanics of Cement: Polydisperse Colloidal Packing. Physical Review Letters. DOI: 10.1103/PhysRevLett.109.155503
Meanwhile, there’s a technical group in Spain working on ‘biological’ concrete. From the Dec. 20, 2012 news item on ScienceDaily,
In studying this concrete, the researchers at the Structural Technology Group of the Universitat Politècnica de Catalunya • BarcelonaTech (UPC) have focused on two cement-based materials. The first of these is conventional carbonated concrete (based on Portland cement), with which they can obtain a material with a pH of around 8. The second material is manufactured with a magnesium phosphate cement (MPC), a hydraulic conglomerate that does not require any treatment to reduce its pH, since it is slightly acidic.
On account of its quick setting properties, magnesium phosphate cement has been used in the past as a repair material. It has also been employed as a biocement in the field of medicine and dentistry, indicating that it does not have an additional environmental impact.
The innovative feature of this new (vertical multilayer) concrete is that it acts as a natural biological support for the growth and development of certain biological organisms, to be specific, certain families of microalgae, fungi, lichens and mosses.
Here’s a description of the ‘biological’ concrete and its layers,
In order to obtain the biological concrete, besides the pH, other parameters that influence the bioreceptivity of the material have been modified, such as porosity and surface roughness. The result obtained is a multilayer element in the form of a panel which, in addition to a structural layer, consists of three other layers: the first of these is a waterproofing layer situated on top of the structural layer, protecting the latter from possible damage caused by water seeping through.
The next layer is the biological layer, which supports colonisation and allows water to accumulate inside it. It acts as an internal microstructure, aiding retention and expelling moisture; since it has the capacity to capture and store rainwater, this layer facilitates the development of biological organisms.
The final layer is a discontinuous coating layer with a reverse waterproofing function. [emphasis mine] This layer permits the entry of rainwater and prevents it from escaping; in this way, the outflow of water is redirected to where it is aimed to obtain biological growth
This work is designed for a Mediterranean climate and definitely not for rain forests such as the Pacific Northwest which, climatologically, is a temperate rainforest.
The ScienceDaily news item ends with this information about future research and commercialization,
The research has led to a doctoral thesis, which Sandra Manso is writing. At present, the experimental campaign corresponding to the phase of biological growth is being conducted, and this will be completed at the UPC and the University of Ghent (Belgium). This research has received support from Antonio Gómez Bolea, a lecturer in the Faculty of Biology at the University of Barcelona, who has made contributions in the field of biological growth on construction materials.
At present, a patent is in the process of being obtained for this innovative product, and the Catalan company ESCOFET 1886 S.A., a manufacturer of concrete panels for architectural and urban furniture purposes, has already shown an interest in commercialising the material.
Almost at the same time, the US Transport Research Board (a division of the US National Research Council) released this Dec. 19, 2012 announcement about their latest circular,
TRB Transportation Research Circular E-C170: Nanotechnology in Concrete Materials: A Synopsis explore promising new research and innovations using nanotechnology that have the potential to result in improved mechanical properties, volume change properties, durability, and sustainability in concrete materials.
The report is 44 pp (PDF version) and provides an in-depth look (featuring some case studies) at the research not just of nanomaterials but also nanoelectronics and sensors as features in nanotechoology-enabled concrete and cement products.
There you have it, a festival of cement and concrete.