الفهرس 
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Abstract
Cement fillers are carefully selected which enhance cement workability or water retention; since cement is a binding material. They can be inert or have slightly hydraulic or pozzolanic properties. Fillers are normally either limestone or any inert material such as silica; and recently fillers are nanoparticles materials. The main advances have been in the nano-science of cementations materials with an increase in the knowledge and understanding of basic phenomena in cement at the nano-scale (e.g., structure and mechanical properties of the main hydrate phases, origins of cement cohesion, cement hydration, interfaces in concrete, and mechanisms of degradation). Using of TiO2 nanoparticles (i.e., less than 100×10-9m) have a great effect on reinforcing the mechanical strength of cement pastes as shown and discussed in the work.
Cement and concrete are a multidisciplinary area of research where nanotechnology potentially offers the opportunity; to enhance the understanding of cement and concrete behavior; to engineer its chemical, physical and mechanical properties and to lower production and ecological cost of construction materials. Recent work in the area of cement and concrete materials researches have shown the potential of improving their properties by modifying the structure of cement hydrates, the addition of nanoparticles and controlling the delivery of admixtures. The results showed that filler reduced the setting time and total porosity, improved the strength, freed lime content, combined water content and bulk density of cement pastes; due to the pozzolanic effect of micro white sand, that replaced clinker and enhance an excess amount of hydration products. It can be concluded that limestone fills the pores between cement particles; due to the formation of carboaluminate, while micro sand increases the hydration C-S-H product. TiO2 nanoparticles show great efficiency in enhancing the mechanical strength of cement paste; due to the incorporation efficiency of nanoparticles as active sites for gel Tobermorite C-S-H fibers growth during hydration.