Development of nano cement concrete by top-down and bottom-up nanotechnology concept

Nanotechnology is an emerging field of science that allows access to control and manipulate the inner characteristics of matter at the nano-scale level leading to explore and understand the exceptionally superior macro-scale behavior of matter. Advancements of the nanotechnology in the field of civil engineering, especially in construction materials science have revealed the benefits in developing a new generation of concrete with enhanced properties such as high mechanical strength and more durability with desired stress-strain behavior. In fact, the prime advances in the field of nano cement science have been identified to be the improvement in the knowledge to understand the basic phenomena at the nanoscale of cement (e.g., cement hydration, origins of cement cohesion, structure and properties of the hydrate phases, interface interaction, and concrete degradation mechanisms). Though the significant progress in developing nano-engineered cement concrete has been achieved by incorporating nano additives/nano fiber reinforcement, however, a limited attention has been paid on the production of nano-sized cement particle by top-down method (deconstructed from larger structures into their smaller) and the development of an alternative cementitious material by bottom-up methodology (through a process of assembling the atoms or molecules in the nanometer scale). This chapter focuses on the impact of top-down and the bottom-up nanotechnology concept on the synthesis, production, characterization and properties evaluation of nano cementitious materials providing two case studies.