CAMP Annual Report: Page 10
Use of Waste and Recycled Materials in Concrete
Professor Narayanan Neithalath, of Clarkson’s Department of Civil and Environmental Engineering, is primarily interested in the area of cement based materials, including concretes and structural composites. The use of concrete throughout the world is second only to water. With an ever increasing demand for infrastructure including roads, bridges, and buildings, the anticipated use of concrete is expected to increase from the present 12 billion metric tons a year to 18 billion metric tons a year in the next 10 years. This places an enormous strain on the natural resources since all the concrete ingredients are mined from nature. In addition, the production of Portland cement is responsible for a share of the global carbon dioxide emissions. Hence the best possible way to reduce the impact of concrete production on the environment is to incorporate large amounts of waste and recycled materials in concrete. Sustainable technologies like the use of industrial wastes such as fly ash and blast furnace slag, and recycling old concrete as aggregates in new concrete are being practiced extensively. The research at Clarkson University on sustainable concrete materials focuses on the use of non-standard secondary cementing materials for concrete like fine glass powder and high carbon fly ash that have the potential to replace a portion of cement in concrete, thus making the concrete more “green”, and economical. The potential for using fine limestone powder that is a quarry waste in the production of high performance and self consolidating concretes that require higher amounts of fine materials is also being explored. With research funding from the Environmental Services Unit of the Empire State Development, NYSERDA, and NYSTAR, research at Clarkson has focused on development, characterization, and optimization of concretes including these secondary cementing and filler materials. The project on utilization of fine glass powder has resulted in development of concrete mixture proportions to be used by local concrete and block manufacturers. This research was chosen by National Ready Mix Concrete Association to be featured in the fall issue of their Concrete InFocus magazine.
Nafion is a synthetic polyelectrolyte that found use in fuel cells for the fabrication of the proton exchange membrane. CAMP Professor Sergiy Minko and his research group have developed an expertise in the study of the interaction of polyelectrolyte chains with solid substrates on the level of single molecules. Understanding of the interaction of the Nafion with graphite and noble metal nanoparticles is vitally important for the development of the efficient device. The interaction can be evaluated through the conformation of the adsorbed chain. Conformation of a hydrophobic polyelectrolyte chain in aqueous solutions (conditions of poor solvent) is balanced by strong hydrophobic interactions of the polymer backbone, electrostatic interactions (repulsion) between ionized functional groups and entropic energy of the Gaussian coil. At high charge density of the polymeric chain, the electrostatic repulsion may dominate and the chain posses extended coil conformation.
Figure 3. Chemical Structure of Nafion
Nafion is a very hydrophobic polyelectrolyte (ionomer) which can be dissolved in water-ethanol mixtures. See Figure 3. Adsorption of Nafion on the surface of C substrates is driven by hydrophobic interactions, interactions with ionized functional groups (-COO-) on the C surface (resulting from surface oxidation), and electrostatic interactions with adsorbed ions in solution. In the current research project funded by GM, Professor Minko’s group is studying the conformations of single Nafion molecules on graphite substrates.
Durable Humidity Sensor
CAMP Professor Feng Hua and his group have developed a transparent humidity sensor. The sensing layer is made of a porous crosslinked polyion multilayer. The porous structure of the hydrophilic polyions enables more moisture absorption per unit volume. The top electrode that covers the sensing material is made porous by using a printed photomask with controlled darkness on a plastic transparency. The dense holes on the electrode improve the response time of humidification and dessication. The covalent bond in the polyion network improves the durability of the polyion sensor in a high-humidity environment. The sensor was soaked in water for days to test its durability. After a portion of the non-crosslinked polyions were dissolved, the reading of the sensor under moist conditions became stable. The see-through structure of the sensor enables it to work for special applications such as a leaf moisture sensor, which imposes less influence to the sunshine intensity on the leaf and can tell when the crops need water.
CAMP’s Dr. Dana Barry displays her newest book.
CAMP’s Dr. Dana Barry Receives Apex Award and Serves as Keynote Speaker in Japan
Dr. Dana M. Barry, senior technical writer and editor at Clarkson University’s Center for Advanced Materials Processing (CAMP), received an APEX 2008 Award for Publication Excellence from Communications Concepts Inc. in Springfield, Va. This is the 13th consecutive time that she has won this award, which is based on editorial content and overall communications effectiveness and excellence. Her winning entry, the “CAMP Annual Report Newsletter 2006-2007,” faired extremely well in the exceptionally intense competition. There were close to 4,500 entries in the competition and approximately 1,400 awards of excellence were distributed in 110 subcategories of 11 major areas. Dr. Barry (Scientific Board President for Ansted University) also served as a Visiting Professor for Suzuka National College of Technology and the Keynote Speaker at an Education Symposium in Suzuka City, Japan during the month of June. Her collaborator for creative education projects is Professor Hideyuki Kanematsu of Japan. In addition, Barry coauthored the new book Plan, Develop, Display, Present Science Projects. It is written with Robert W. Smith and published by Teacher Created Resources in 2008.