CEE April-June 2012

Computational material modelling techniques With the increase in computational data processing technologies, based on calculations and computational simulation modelling, ab-into molecular Figure2a. Atomic Configurations of Tobermorite(/, 2) Model {10] dynamics, molecular statics and Monte Carlo like developed methods can also be used to determine the properties of cement and concrete. Various cement and concrete properties which are very difficult to obtain experimentally, can be determined by using digital simulation methods mentioned above. Using "tobermorite and Jennite" example being a proper structural prototype of CSH, position of the hydrogen bonds in CSH structure and position and movements of the interlayer water can be determined [10, 23]. 111 ' 1ll"' T mechanical and chemical behaviour of concrete become easier to describe [24, 25]. Development of cement and concrete structures by using Nanotechnology and its engineering applications Three main parameters are important in adjusting the appropriate crystal structure of Portland cement which is produced about 2 to 3 billions tonne per year as hydraulic binding material: Mineral composition of the raw materials, reactivity of the raw mixture and firing conditions in the rotary kiln. Molecular Dynamics modelling technique in atomic dimensions is effective in dynamic evaluation Figure2b. A typical MD simulation cell used in the modelling [24]. Using nanotechnology in cement and concrete production chemical and physical properties can be controlled. Self-healing solutions of equilibrium and non-equilibrium conditions. It is observed that by this technique that the decrease in the tensi le strength is due to presence of water. By understanding the interaction of the components with their environment at molecular level using this technique it becomes possible to explain the durability of the system in a more effective manner. In addition to this by increasing the calcium content that is by increasing Ca-Si ratio, it was observed that the polymerization of silicate chains slowed down and their forming loop shapes and three– dimensional structures was prevented. As such structural features are better understood the concretes which can repair themselves after a small scale fracture or cracking can be manufactured by using a nano additives. The material structure can be examined at atomic level. By using optical carbon fibres transparent concretes various architectural purposes can be designed. More economical structures of smaller cross-sections can be made. Amount of clinker necessity can be decreased. The amount of carbon dioxide release to the atmosphere can be reduced and thus carbon and oxygen can be recovered separately. Using nantotechnology orange-like two layered structures with a lower simple part and a 13