Hello everyone! Today, I am going to take a break on my Karuna House series and write a post about cellulose nanocrystals. Cellulouse nanocrystals are the material that gives plants and trees their stiffness. Their dimensions are 3 nanometers wide by 500 nanometers long – about .1% the width of a grain of sand. They can be easily harvested with a sustainable process and can be produced from paper waste as well. A recent study by Purdue University has found that these nanocrystals are light weight, have high strength, are highly resistant and have the stiffness of steel. “It (the research) is also the first step towards a multiscale modeling approach to understand and predict the behavior of individual crystals, the interaction between them, and their interaction with other materials,” Zavattieri said. “This is important for the design of novel cellulose-based materials as other research groups are considering them for a huge variety of applications, ranging from electronics and medical devices to structural components for the automotive, civil and aerospace industries.” The article shown in the link here, http://goo.gl/8Pl8LB, provides a quick overview of characteristics with extremely basic explanations in regards to applications and I am going to expand on possible applications as they pertain to structural engineering.
Organic Polymer for Concrete:
Fiber reinforced concrete can be designed to reduce the amount of steel required. In this way, cost and heavy material requirements can be reduced in the construction process. I believe that cellulose nanocrystals can be used in the same way. They can be placed in concrete and improve the tension strength where needed. These also have the added benefit of being more sustainable and less expensive in regards to material accessibility as compared to fiber reinforcement. That being said, it is not clear if the cost of the production once the material is obtained would be out-weigh the cost savings in accessibility. More research and practical application of the production process is needed to determine that.
Reinforcement Against Cracking:
A very common issue with concrete infrastructure is cracking. Currently, when cracking starts occurring at the base of a beam, a method where steel reinforcement is bolted into the concrete is used to prevent further expansion of the cracks. While it is an efficient solution in regards to time and money, steel is not as environmentally friendly a material. Along with that, once research into production and application is completed, the amount of time and money can be reduced to that of the steel reinforcement method. This means that an approach where an organic polymer sheet covered by a layer shotcrete could be a better solution at that point.
Additional Reinforcement for Timber Structures:
Engineered lumber is a recent development in timber design. These are basic timber building elements that are created from pieces of timber. Some good examples of this are cross laminated timber/particle board panels and glulam beams /columns. Along with that, other applications such timber restoration apply this same concept of combining pieces of timber to create a stronger building element. The same type of organic polymer sheet used for reinforcement against cracking could also be used to provide some extra tension strength in these situations. This would be very beneficial in timber elements that are designed to resist high levels of flexure. Another added benefit would be that the nanocrystals are extremely thin and can be applied in design with very tight tolerances.
Cellulose nanocrystals could have a lot promising a applications for structural engineering designs and I look forward to seeing what improvement can be made using this material. What is your opinion on the possible applications mentioned above? Are there any other structural engineering applications that you can see this material for? Thanks for your time and have a good week!
Zavattieri, Pablo. “Cellulose Crystals Are a Possible ‘Green’ Wonder Material.” Red Orbit Online. December 17, 2013. http://goo.gl/8Pl8LB